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1.  Change in N-terminal-pro-B-type-natriuretic-peptide and the risk of sudden death, stroke, myocardial infarction, and all-cause mortality in diabetic dialysis patients 
European Heart Journal  2008;29(17):2092-2099.
Aims
N-terminal-pro-B-type-natriuretic-peptide (NT-pro-BNP) concentrations are altered in renal failure. This study examined the effect of baseline and change from baseline NT-pro-BNP on cardiovascular outcome and mortality in haemodialysis patients.
Methods and results
On the basis of the German Diabetes and Dialysis Study, which evaluated atorvastatin in 1255 type 2 diabetes mellitus (T2DM) haemodialysis patients (median follow-up 4 years), the impact of NT-pro-BNP on pre-specified, adjudicated endpoints was investigated: sudden death (SD; n = 160), stroke (n = 99), myocardial infarction (MI; n = 200), cardiovascular events (CVEs: cardiac death, MI, stroke; n = 465), all-cause mortality (n = 612). Patients with baseline NT-pro-BNP ≥9252 pg/mL (fourth quartile) exhibited a more than four-fold risk of stroke [hazard ratio (HR) 4.1; 95% confidence interval (CI) 2.0–8.4] and a more than two-fold risk of SD (HR 2.0; 95% CI 1.2–3.3), CVE (HR 2.0; 95% CI 1.5–2.7), and mortality (HR 2.1; 95% CI 1.6–2.7) compared with patients with baseline NT-pro-BNP ≤ 1433 pg/mL (first quartile). Change in NT-pro-BNP was strongly associated with SD, CVE, and mortality. Doubling of NT-pro-BNP increased the risk of death by 46% (95% CI 1.1–2.0). Neither baseline nor change in NT-pro-BNP was significantly associated with MI.
Conclusion
Increasing NT-pro-BNP is a risk factor for SD, CVE, and mortality in haemodialysis patients with T2DM. Whether NT-pro-BNP-guided treatment improves outcome needs to be evaluated prospectively.
doi:10.1093/eurheartj/ehn278
PMCID: PMC2519248  PMID: 18617483
NT-pro-BNP; Serial measurement; Cardiovascular events; Mortality; Haemodialysis; Diabetes mellitus
2.  Homoarginine, heart failure, and sudden cardiac death in haemodialysis patients 
European Journal of Heart Failure  2011;13(8):852-859.
Aims
Sudden cardiac death (SCD) is a major contributor to the excess mortality of patients on maintenance dialysis. Homoarginine deficiency may lead to decreased nitric oxide availability and endothelial dysfunction. Based on this rationale we assessed whether homoarginine deficiency is a risk factor for SCD in dialysis patients.
Methods and results
This study examined the association of homoarginine with cardiovascular outcomes in 1255 diabetic haemodialysis patients from the German diabetes and dialysis study. During a median of 4 years of follow-up, hazard ratios (HR) (95% CI) for reaching the following pre-specified, adjudicated endpoints were determined: SCD, myocardial infarction, stroke, death due to heart failure, and combined cardiovascular events. There was a strong association of low homoarginine concentrations with the presence of congestive heart failure and left ventricular hypertrophy as well as increased levels of brain natriuretic peptide. Per unit decrease in homoarginine, the risk of SCD increased three-fold (HR 3.1, 95% CI 2.0–4.9), attenuating slightly in multivariate models (HR 2.4; 95% CI 1.5–3.9). Patients in the lowest homoarginine quintile experienced a more than two-fold increased risk of SCD, and more than three-fold increased risk of heart failure death than patients in the highest quintile, which accounted for the high incidence of combined cardiovascular events. Low homoarginine showed a trend towards increased risk of stroke, however, myocardial infarction was not meaningfully affected.
Conclusion
Low homoarginine is a strong risk factor for SCD and death due to heart failure in haemodialysis patients. Further studies are needed to elucidate the underlying mechanisms, offering the potential to develop new interventional strategies.
doi:10.1093/eurjhf/hfr056
PMCID: PMC3143829  PMID: 21791541
Homoarginine; Sudden cardiac death; Heart failure; Amino acids; Haemodialysis
3.  Aldosterone and cortisol affect the risk of sudden cardiac death in haemodialysis patients 
European Heart Journal  2012;34(8):578-587.
Background
Sudden cardiac death is common and accounts largely for the excess mortality of patients on maintenance dialysis. It is unknown whether aldosterone and cortisol increase the incidence of sudden cardiac death in dialysis patients.
Methods and results
We analysed data from 1255 diabetic haemodialysis patients participating in the German Diabetes and Dialysis Study (4D Study). Categories of aldosterone and cortisol were determined at baseline and patients were followed for a median of 4 years. By Cox regression analyses, hazard ratios (HRs) were determined for the effect of aldosterone, cortisol, and their combination on sudden death and other adjudicated cardiovascular outcomes. The mean age of the patients was 66 ± 8 years (54% male). Median aldosterone was <15 pg/mL (detection limit) and cortisol 16.8 µg/dL. Patients with aldosterone levels >200 pg/mL had a significantly higher risk of sudden death (HR: 1.69; 95% CI: 1.06–2.69) compared with those with an aldosterone <15 pg/mL. The combined presence of high aldosterone (>200 pg/mL) and high cortisol (>21.1 µg/dL) levels increased the risk of sudden death in striking contrast to patients with low aldosterone (<15 pg/mL) and low cortisol (<13.2 µg/dL) levels (HR: 2.86, 95% CI: 1.32–6.21). Furthermore, all-cause mortality was significantly increased in the patients with high levels of both hormones (HR: 1.62, 95% CI: 1.01–2.62).
Conclusions
The joint presence of high aldosterone and high cortisol levels is strongly associated with sudden cardiac death as well as all-cause mortality in haemodialysed type 2 diabetic patients. Whether a blockade of the mineralocorticoid receptor decreases the risk of sudden death in these patients must be examined in future trials.
doi:10.1093/eurheartj/ehs361
PMCID: PMC3578266  PMID: 23211232
Aldosterone; Cortisol; Sudden cardiac death; Cardiovascular events; Mortality; Kidney disease
4.  The association between parathyroid hormone and mortality in dialysis patients is modified by wasting 
Nephrology Dialysis Transplantation  2009;24(10):3151-3157.
Background. The association between parathyroid hormone (PTH) level and mortality in dialysis patients is controversial. We hypothesized that wasting, a common condition potentially related to adynamic bone disease, modifies the association of PTH with mortality and cardiovascular events (CVE), respectively.
Methods. We analysed data from 1255 diabetic haemodialysis patients, participating in the German Diabetes and Dialysis Study between 1998 and 2004. The patients were stratified by the presence or absence of wasting (albumin ≤3.8 versus albumin >3.8 g/dL; BMI ≤23 versus BMI >23 kg/m2). Using Cox regression analyses, we calculated the risks of (1) all-cause mortality and (2) CVE according to baseline PTH levels. All analyses were adjusted for age, sex, atorvastatin treatment, duration of dialysis, comorbidity, HbA1c, phosphate, calcium, blood pressure, haemoglobin and C-reactive protein.
Results. Patients had a mean age of 66 ± 8 years, and 54% were male. Among patients without wasting (albumin >3.8 g/dL, n = 586), the risks of death and CVE during 4 years of follow-up significantly increased by 23% and 20% per unit increase in logPTH. Patients in the highest PTH tertile had a 74% higher risk of death (HRadj 1.74, 95% CI 1.27–2.40) and a 49% higher risk of CVE (HRadj 1.49, 95% CI 1.05–2.11) compared to patients in the lowest PTH tertile. In contrast, no effect was found in patients with wasting. Accordingly, additional analyses in strata of BMI showed that PTH significantly impacted on death and CVE [HR(logPTH)adj 1.15 and 1.14, respectively] only in patients without, but not in patients with, wasting.
Conclusions. Wasting modifies the association of PTH with adverse outcomes in diabetic dialysis patients. High PTH levels are of concern in the patients without wasting, while the effect of PTH on mortality is nullified in the patients with wasting.
doi:10.1093/ndt/gfp260
PMCID: PMC2747498  PMID: 19474272
cardiovascular events; haemodialysis; mortality; parathyroid hormone; wasting
5.  Vitamin D, Parathyroid Hormone and Sudden Cardiac Death: Results from the Cardiovascular Health Study 
Hypertension  2011;58(6):1021-1028.
Recent studies have demonstrated greater risks of cardiovascular events and mortality among persons who have lower 25-hydroxyvitamin D (25-OHD) and higher parathyroid hormone (PTH) levels. We sought to evaluate the association between markers of mineral metabolism and sudden cardiac death (SCD) among the 2,312 participants from the Cardiovascular Health Study who were free of clinical cardiovascular disease at baseline. We estimated associations of baseline 25-OHD and PTH concentrations individually and in combination with SCD using Cox proportional hazards models after adjustment for demographics, cardiovascular risk factors, and kidney function. During a median follow-up of 14 years, there were 73 adjudicated SCD events. The annual incidence of SCD was greater among subjects who had lower 25-OHD concentrations: 2 events per 10,000 for 25-OHD ≥ 20 ng/ml and 4 events per 10,000 for 25-OHD < 20 ng/ml. Similarly, SCD incidence was greater among subjects who had higher PTH concentrations: 2 events per 10,000 for PTH ≤ 65 pg/ml and 4 events per 10,000 for PTH > 65 pg/ml. Multivariate adjustment attenuated associations of 25-OHD and PTH with SCD. Finally, 267 participants (11.7% of the cohort) had high PTH and low 25-OHD concentrations. This combination was associated with a more than 2-fold risk of SCD after adjustment (hazard ratio 2.19, 95% confidence interval 1.17, 4.10, p=0.017) compared to participants with normal levels of PTH and 25-OHD. The combination of lower 25-OHD and higher PTH concentrations appears to be associated independently with SCD risk among older adults without cardiovascular disease.
doi:10.1161/HYPERTENSIONAHA.111.179135
PMCID: PMC3337033  PMID: 22068871
Sudden cardiac death; Vitamin D; Parathyroid hormone; Elderly; Risk Factors
6.  Plasma Fatty Acid Binding Protein 4 and Risk of Sudden Cardiac Death in Older Adults 
Although fatty acid binding protein 4 (FABP4) may increase risk of diabetes and exert negative cardiac inotropy, it is unknown whether plasma concentrations of FABP4 are associated with incidence of sudden cardiac death (SCD). We prospectively analyzed data on 4,560 participants of the Cardiovascular Health Study. FABP4 was measured at baseline using ELISA, and SCD events were adjudicated through review of medical records. We used Cox proportional hazards to estimate effect measures. During a median followup of 11.8 years, 146 SCD cases occurred. In a multivariable model adjusting for demographic, lifestyle, and metabolic factors, relative risk of SCD associated with each higher standard deviation (SD) of plasma FABP4 was 1.15 (95% CI: 0.95–1.38), P = 0.15. In a secondary analysis stratified by prevalent diabetes status, FABP4 was associated with higher risk of SCD in nondiabetic participants, (RR per SD higher FABP4: 1.33 (95% CI: 1.07–1.65), P = 0.009) but not in diabetic participants (RR per SD higher FABP4: 0.88 (95% CI: 0.62–1.27), P = 0.50), P for diabetes-FABP4 interaction 0.049. In summary, a single measure of plasma FABP4 obtained later in life was not associated with the risk of SCD in older adults overall. Confirmation of our post-hoc results in nondiabetic people in other studies is warranted.
doi:10.1155/2013/181054
PMCID: PMC3888692  PMID: 24455402
7.  Long-term prognosis associated with J-point elevation in a large middle-aged biracial cohort: the ARIC study 
European Heart Journal  2011;32(24):3098-3106.
Aims
An association has been described between death from arrhythmia and early repolarization, an electrocardiogram pattern characterized by elevation of the QRS–ST junction (J-point). Little is known about this relationship in non-white populations. This study examines the relationship between J-point elevation (JPE) and sudden cardiac death (SCD) and whether this relationship differs by race or sex.
Methods and results
A total of 15 141 middle-aged subjects from the prospective, population-based Atherosclerosis Risk in Communities (ARIC) study were included in this analysis. The primary endpoint was physician-adjudicated SCD occurring from baseline (1987–1989) through December 2002, secondary endpoints were fatal and non-fatal coronary events and all-cause mortality occurring through December 2007. J-point elevation was defined as J-point amplitude ≥0.1 mV. Pre-specified subgroup analyses by sex and race were conducted. J-point elevation in any lead was present in 1866 subjects (12.3%). After adjustment for demographic, clinical, lifestyle, and laboratory variables, JPE was not significantly related to SCD in the overall sample [adjusted hazard ratio (HR), 1.23; 95% confidence interval (CI), 0.87–1.75]. However, significant interactions were present between race and JPE (P = 0.006) and between sex and JPE (P = 0.020). J-point elevation was significantly predictive of SCD in whites (adjusted HR, 2.03; 95% CI, 1.28–3.21) and in females (adjusted HR, 2.54; 95% CI, 1.34–4.82).
Conclusion
Our results suggest that JPE is associated with an increased risk of SCD in whites and in females, but not in blacks or males. Further studies are needed to clarify which subgroups of individuals with JPE are at increased risk for adverse cardiac events.
doi:10.1093/eurheartj/ehr264
PMCID: PMC3236999  PMID: 21785106
Electrocardiography; Sudden cardiac death; J-point elevation; Epidemiology
8.  Impact of age and sex on sudden cardiovascular death following myocardial infarction 
Heart  2002;88(6):573-578.
Objective: To evaluate and compare the risk of sudden cardiovascular death (SCD) and non-SCD after myocardial infarction (MI) associated with age and sex.
Design: Cohort study of patients admitted with an enzyme verified acute MI and discharged alive. Patients were followed up for up to four years.
Patients: 5983 consecutive hospital survivors of acute MI were enrolled in the TRACE (trandolapril cardiac evaluation) registry from 1990–92. Four age groups were prespecified: < 56, 56–65, 66–75, and ≥ 76 years.
Main outcome measures: SCD was defined as cardiovascular death within one hour of onset of symptoms.
Results: There were 536 SCD and 725 non-SCD. SCD mortality was 4.8% in the youngest and 15.7% in the oldest age groups. Non-SCD mortality was 3.5% and 25%, respectively. The ratio of SCD to non-SCD mortality varied from 1.44 in the youngest (< 56 years) to 0.55 in the oldest patients (≥ 76 years). Age significantly increased both SCD and non-SCD risk (p < 0.0001), but the increase in non-SCD risk was 40% higher (p < 0.0001). Male sex was associated with increased risk of SCD independently of age (risk ratio 1.34, p < 0.005). However, the absolute three year probability of SCD among women older than 66 years exceeded 10%.
Conclusions: Compared with non-SCD the risk of SCD is relatively highest in the younger age groups, but the absolute risk of SCD is much higher among the upper age groups than the younger. The risk of SCD was slightly lower in women but not enough to warrant a different treatment strategy.
PMCID: PMC1767447  PMID: 12433881
sudden death; women; aging; myocardial infarction
9.  Depression and Risk of Sudden Cardiac Death and Coronary Heart Disease in Women: Results from the Nurses’ Health Study 
Objectives
We assessed the association between depression and sudden cardiac death (SCD) and cardiac events among individuals without baseline coronary heart disease (CHD).
Background
Depression is a risk factor for cardiac events and mortality among those with CHD, possibly from arrhythmia.
Methods
We studied depressive symptoms, and a proxy variable for clinical depression consisting of severe symptoms and/or antidepressant medication use, and their relationship to cardiac events in the Nurses’ Health Study. Questionnaires in 1992, 1996, and 2000 assessed symptoms with the Mental Health Index (MHI-5), and antidepressant use was assessed in 1996 and 2000. Primary endpoints included SCD, fatal CHD, and non-fatal myocardial infarction (MI).
Results
Among 63,469 women without prior CHD/stroke in 1992, 7.9% had MHI-5 scores (<53) previously found to predict clinical depression. Depressive symptoms were associated with CHD events, and the relationship was strongest for fatal CHD, where the association remained significant even after controlling for CHD risk factors (HR=1.49; 95% CI 1.11–2.00 for MHI-5 score<53). In models from 1996 onward, our proxy variable for clinical depression was most associated with SCD in multivariable models (HR=2.33, 95% CI 1.47–3.70), and this risk was primarily due to a specific relationship between antidepressant use and SCD (HR=3.34, 95% CI 2.03–5.50).
Conclusions
In this cohort of women without baseline CHD, depressive symptoms were associated with fatal CHD, and a measure of clinical depression including antidepressant use was specifically associated with SCD. Although antidepressant use may be a marker of worse depression, its specific association with SCD merits further study.
CONDENSED ABSTRACT
We prospectively analyzed the association between depression and cardiac events in the Nurses’ Health Study. Symptoms of depression as measured by Mental Health Index (MHI-5) score were directly associated with risk of CHD events, and the relationship was strongest for fatal CHD. A proxy variable for clinical depression comprised of MHI-5 score<53 or antidepressant use was strongly associated with sudden cardiac death (SCD), primarily due to a specific relationship between antidepressant use and SCD. Although antidepressant use may be a marker of worse depression, its specific association with SCD merits further study.
doi:10.1016/j.jacc.2008.10.060
PMCID: PMC2664253  PMID: 19281925
sudden cardiac death; coronary disease; epidemiology; women
10.  Associations of Plasma 25-Hydroxyvitamin D and 1,25-Dihydroxyvitamin D Concentrations With Death and Progression to Maintenance Dialysis in Patients With Advanced Kidney Disease 
Background
Low vitamin D concentrations are prevalent in chronic kidney disease (CKD) patients. We investigated the relationship between plasma 25-hydroxyvitamin D (25(OH)D) or 1,25-dihydroxyvitamin D (1,25(OH)2D) concentrations with death, cardiovascular events (CVE) and dialysis initiation in patients with advanced CKD. Study Design: The Homocysteine Study was a randomized double-blind trial evaluating the effects of high doses of folic acid on death and chronic dialysis initiation in patients with advanced CKD (stage 4 and 5 not yet on dialysis). 25(OH)D and 1,25(OH)2D concentrations were measured in stored plasma samples obtained 3 months after trial initiation and evaluated at clinically defined cutoffs (<10, 10-30, and >30 ng/mL) and tertiles (< 15, 15-22, and >22 pg/mL), respectively. Cox-proportional hazard models were used to examine the association between vitamin D concentrations and clinical outcomes.
Setting & Participants
1,099 patients with advanced CKD from 36 Veteran Affairs Medical Centers
Predictors
25(OH)D and 1,25(OH)2D concentrations
Outcomes
Death, CVE and time to initiation of chronic dialysis.
Results
After a median follow-up period of 2.9 years, 41% (n=453) died, while 56% (n=615) initiated dialysis. Mean 25(OH)D and 1,25(OH)2D concentrations were 21±10 ng/mL and 20±11 pg/mL, respectively. After adjustment for potential confounders, the lowest tertile of 1,25(OH)2D was associated with death (HR, 1.33; 95% CI, 1.01-1.74) and initiation of chronic dialysis (HR, 1.78; 95% CI, 1.40-2.26), compared to the highest tertile. The association with death and initiation of dialysis was moderately attenuated after adjustment for plasma fibroblast growth factor-23 (FGF23) concentrations (HRs of lower tertiles of 1.20 [95% CI, 0.91-1.58] and 1.56 [95% CI, 1.23-1.99], respectively, compared to highest tertile). There was no association between 25(OH)D concentrations and outcomes.
Limitations
Participants were mostly male.
Conclusions
Low plasma 1,25(OH)2D concentrations are associated with death and initiation of chronic dialysis in advanced CKD. Fibroblast growth factor-23 may attentuate this relationship.
doi:10.1053/j.ajkd.2012.04.014
PMCID: PMC3439559  PMID: 22621970
11.  The prevalence of electrocardiographic early repolarization in an adult cohort with chronic kidney disease and its impact upon all-cause mortality and progression to dialysis 
Background: Electrocardiographic early repolarization (ER) occurring in <5% of general/atherosclerotic populations, is a marker of sudden cardiac death (SCD). The prevalence of ER in chronic kidney disease (CKD) patients, in whom SCD is common, is unknown. We aimed to determine the prevalence, contributing factors, and relationship of ER to all-cause mortality and progression to dialysis in CKD patients.
Methods: A retrospective study of 197 patients with stage 3–5 CKD. Full demographic data were collected including cardiovascular risk factors and history. All patients underwent a 12-lead ECG, analysed for the presence of ER and other ECG findings. ER was defined as elevation of the QRS-ST junction (J point) by at least 0.1 mV from baseline with slurring/notching of the QRS complex. The primary and secondary endpoints were all cause mortality and progression to dialysis respectively at 1 year. To control for the effects of CKD, we evaluated the ECGs of 39 healthy renal transplant donors (RTD).
Results: CKD patients had a mean age of 61.5 (±16.1). Prevalence of ER in pre-dialysis patients with CKD stage 4 and 5 was higher than in RTD (26.4 vs. 7.7%, p = 0.02). ER frequency increased with CKD stage (stage 3: 7.7%, stage 4: 29.7%, and pre-dialysis stage 5: 24.6%), but decreased in dialysis patients (13%). On multivariate analysis only the QRS duration was a significant independent predictor of ER (OR 0.97, 95% CI, 0.94–0.99, p = 0.01). At 1-year follow-up, there were 24 (12%) deaths in the patients with CKD of whom 5 (21%) had ER. ER was not a predictor of all cause mortality (p = 1.00) and had no effects on the rate of progression to dialysis (p = 0.67).
Conclusions: ER is more common in pre-dialysis CKD patients, compared to healthy RTD but is not associated with increased 1-year mortality or entry onto dialysis programs. Further longitudinal studies are indicated to determine whether this increased prevalence of ER is associated with the rate of SCD seen in this population.
doi:10.3389/fphys.2013.00127
PMCID: PMC3668171  PMID: 23755022
early repolarization; chronic kidney disease; sudden cardiac death; dialysis; mortality
12.  Internet-Based Device-Assisted Remote Monitoring of Cardiovascular Implantable Electronic Devices 
Executive Summary
Objective
The objective of this Medical Advisory Secretariat (MAS) report was to conduct a systematic review of the available published evidence on the safety, effectiveness, and cost-effectiveness of Internet-based device-assisted remote monitoring systems (RMSs) for therapeutic cardiac implantable electronic devices (CIEDs) such as pacemakers (PMs), implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy (CRT) devices. The MAS evidence-based review was performed to support public financing decisions.
Clinical Need: Condition and Target Population
Sudden cardiac death (SCD) is a major cause of fatalities in developed countries. In the United States almost half a million people die of SCD annually, resulting in more deaths than stroke, lung cancer, breast cancer, and AIDS combined. In Canada each year more than 40,000 people die from a cardiovascular related cause; approximately half of these deaths are attributable to SCD.
Most cases of SCD occur in the general population typically in those without a known history of heart disease. Most SCDs are caused by cardiac arrhythmia, an abnormal heart rhythm caused by malfunctions of the heart’s electrical system. Up to half of patients with significant heart failure (HF) also have advanced conduction abnormalities.
Cardiac arrhythmias are managed by a variety of drugs, ablative procedures, and therapeutic CIEDs. The range of CIEDs includes pacemakers (PMs), implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy (CRT) devices. Bradycardia is the main indication for PMs and individuals at high risk for SCD are often treated by ICDs.
Heart failure (HF) is also a significant health problem and is the most frequent cause of hospitalization in those over 65 years of age. Patients with moderate to severe HF may also have cardiac arrhythmias, although the cause may be related more to heart pump or haemodynamic failure. The presence of HF, however, increases the risk of SCD five-fold, regardless of aetiology. Patients with HF who remain highly symptomatic despite optimal drug therapy are sometimes also treated with CRT devices.
With an increasing prevalence of age-related conditions such as chronic HF and the expanding indications for ICD therapy, the rate of ICD placement has been dramatically increasing. The appropriate indications for ICD placement, as well as the rate of ICD placement, are increasingly an issue. In the United States, after the introduction of expanded coverage of ICDs, a national ICD registry was created in 2005 to track these devices. A recent survey based on this national ICD registry reported that 22.5% (25,145) of patients had received a non-evidence based ICD and that these patients experienced significantly higher in-hospital mortality and post-procedural complications.
In addition to the increased ICD device placement and the upfront device costs, there is the need for lifelong follow-up or surveillance, placing a significant burden on patients and device clinics. In 2007, over 1.6 million CIEDs were implanted in Europe and the United States, which translates to over 5.5 million patient encounters per year if the recommended follow-up practices are considered. A safe and effective RMS could potentially improve the efficiency of long-term follow-up of patients and their CIEDs.
Technology
In addition to being therapeutic devices, CIEDs have extensive diagnostic abilities. All CIEDs can be interrogated and reprogrammed during an in-clinic visit using an inductive programming wand. Remote monitoring would allow patients to transmit information recorded in their devices from the comfort of their own homes. Currently most ICD devices also have the potential to be remotely monitored. Remote monitoring (RM) can be used to check system integrity, to alert on arrhythmic episodes, and to potentially replace in-clinic follow-ups and manage disease remotely. They do not currently have the capability of being reprogrammed remotely, although this feature is being tested in pilot settings.
Every RMS is specifically designed by a manufacturer for their cardiac implant devices. For Internet-based device-assisted RMSs, this customization includes details such as web application, multiplatform sensors, custom algorithms, programming information, and types and methods of alerting patients and/or physicians. The addition of peripherals for monitoring weight and pressure or communicating with patients through the onsite communicators also varies by manufacturer. Internet-based device-assisted RMSs for CIEDs are intended to function as a surveillance system rather than an emergency system.
Health care providers therefore need to learn each application, and as more than one application may be used at one site, multiple applications may need to be reviewed for alarms. All RMSs deliver system integrity alerting; however, some systems seem to be better geared to fast arrhythmic alerting, whereas other systems appear to be more intended for remote follow-up or supplemental remote disease management. The different RMSs may therefore have different impacts on workflow organization because of their varying frequency of interrogation and methods of alerts. The integration of these proprietary RM web-based registry systems with hospital-based electronic health record systems has so far not been commonly implemented.
Currently there are 2 general types of RMSs: those that transmit device diagnostic information automatically and without patient assistance to secure Internet-based registry systems, and those that require patient assistance to transmit information. Both systems employ the use of preprogrammed alerts that are either transmitted automatically or at regular scheduled intervals to patients and/or physicians.
The current web applications, programming, and registry systems differ greatly between the manufacturers of transmitting cardiac devices. In Canada there are currently 4 manufacturers—Medtronic Inc., Biotronik, Boston Scientific Corp., and St Jude Medical Inc.—which have regulatory approval for remote transmitting CIEDs. Remote monitoring systems are proprietary to the manufacturer of the implant device. An RMS for one device will not work with another device, and the RMS may not work with all versions of the manufacturer’s devices.
All Internet-based device-assisted RMSs have common components. The implanted device is equipped with a micro-antenna that communicates with a small external device (at bedside or wearable) commonly known as the transmitter. Transmitters are able to interrogate programmed parameters and diagnostic data stored in the patients’ implant device. The information transfer to the communicator can occur at preset time intervals with the participation of the patient (waving a wand over the device) or it can be sent automatically (wirelessly) without their participation. The encrypted data are then uploaded to an Internet-based database on a secure central server. The data processing facilities at the central database, depending on the clinical urgency, can trigger an alert for the physician(s) that can be sent via email, fax, text message, or phone. The details are also posted on the secure website for viewing by the physician (or their delegate) at their convenience.
Research Questions
The research directions and specific research questions for this evidence review were as follows:
To identify the Internet-based device-assisted RMSs available for follow-up of patients with therapeutic CIEDs such as PMs, ICDs, and CRT devices.
To identify the potential risks, operational issues, or organizational issues related to Internet-based device-assisted RM for CIEDs.
To evaluate the safety, acceptability, and effectiveness of Internet-based device-assisted RMSs for CIEDs such as PMs, ICDs, and CRT devices.
To evaluate the safety, effectiveness, and cost-effectiveness of Internet-based device-assisted RMSs for CIEDs compared to usual outpatient in-office monitoring strategies.
To evaluate the resource implications or budget impact of RMSs for CIEDs in Ontario, Canada.
Research Methods
Literature Search
The review included a systematic review of published scientific literature and consultations with experts and manufacturers of all 4 approved RMSs for CIEDs in Canada. Information on CIED cardiac implant clinics was also obtained from Provincial Programs, a division within the Ministry of Health and Long-Term Care with a mandate for cardiac implant specialty care. Various administrative databases and registries were used to outline the current clinical follow-up burden of CIEDs in Ontario. The provincial population-based ICD database developed and maintained by the Institute for Clinical Evaluative Sciences (ICES) was used to review the current follow-up practices with Ontario patients implanted with ICD devices.
Search Strategy
A literature search was performed on September 21, 2010 using OVID MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, EMBASE, the Cumulative Index to Nursing & Allied Health Literature (CINAHL), the Cochrane Library, and the International Agency for Health Technology Assessment (INAHTA) for studies published from 1950 to September 2010. Search alerts were generated and reviewed for additional relevant literature until December 31, 2010. Abstracts were reviewed by a single reviewer and, for those studies meeting the eligibility criteria full-text articles were obtained. Reference lists were also examined for any additional relevant studies not identified through the search.
Inclusion Criteria
published between 1950 and September 2010;
English language full-reports and human studies;
original reports including clinical evaluations of Internet-based device-assisted RMSs for CIEDs in clinical settings;
reports including standardized measurements on outcome events such as technical success, safety, effectiveness, cost, measures of health care utilization, morbidity, mortality, quality of life or patient satisfaction;
randomized controlled trials (RCTs), systematic reviews and meta-analyses, cohort and controlled clinical studies.
Exclusion Criteria
non-systematic reviews, letters, comments and editorials;
reports not involving standardized outcome events;
clinical reports not involving Internet-based device assisted RM systems for CIEDs in clinical settings;
reports involving studies testing or validating algorithms without RM;
studies with small samples (<10 subjects).
Outcomes of Interest
The outcomes of interest included: technical outcomes, emergency department visits, complications, major adverse events, symptoms, hospital admissions, clinic visits (scheduled and/or unscheduled), survival, morbidity (disease progression, stroke, etc.), patient satisfaction, and quality of life.
Summary of Findings
The MAS evidence review was performed to review available evidence on Internet-based device-assisted RMSs for CIEDs published until September 2010. The search identified 6 systematic reviews, 7 randomized controlled trials, and 19 reports for 16 cohort studies—3 of these being registry-based and 4 being multi-centered. The evidence is summarized in the 3 sections that follow.
1. Effectiveness of Remote Monitoring Systems of CIEDs for Cardiac Arrhythmia and Device Functioning
In total, 15 reports on 13 cohort studies involving investigations with 4 different RMSs for CIEDs in cardiology implant clinic groups were identified in the review. The 4 RMSs were: Care Link Network® (Medtronic Inc,, Minneapolis, MN, USA); Home Monitoring® (Biotronic, Berlin, Germany); House Call 11® (St Jude Medical Inc., St Pauls, MN, USA); and a manufacturer-independent RMS. Eight of these reports were with the Home Monitoring® RMS (12,949 patients), 3 were with the Care Link® RMS (167 patients), 1 was with the House Call 11® RMS (124 patients), and 1 was with a manufacturer-independent RMS (44 patients). All of the studies, except for 2 in the United States, (1 with Home Monitoring® and 1 with House Call 11®), were performed in European countries.
The RMSs in the studies were evaluated with different cardiac implant device populations: ICDs only (6 studies), ICD and CRT devices (3 studies), PM and ICD and CRT devices (4 studies), and PMs only (2 studies). The patient populations were predominately male (range, 52%–87%) in all studies, with mean ages ranging from 58 to 76 years. One study population was unique in that RMSs were evaluated for ICDs implanted solely for primary prevention in young patients (mean age, 44 years) with Brugada syndrome, which carries an inherited increased genetic risk for sudden heart attack in young adults.
Most of the cohort studies reported on the feasibility of RMSs in clinical settings with limited follow-up. In the short follow-up periods of the studies, the majority of the events were related to detection of medical events rather than system configuration or device abnormalities. The results of the studies are summarized below:
The interrogation of devices on the web platform, both for continuous and scheduled transmissions, was significantly quicker with remote follow-up, both for nurses and physicians.
In a case-control study focusing on a Brugada population–based registry with patients followed-up remotely, there were significantly fewer outpatient visits and greater detection of inappropriate shocks. One death occurred in the control group not followed remotely and post-mortem analysis indicated early signs of lead failure prior to the event.
Two studies examined the role of RMSs in following ICD leads under regulatory advisory in a European clinical setting and noted:
– Fewer inappropriate shocks were administered in the RM group.
– Urgent in-office interrogations and surgical revisions were performed within 12 days of remote alerts.
– No signs of lead fracture were detected at in-office follow-up; all were detected at remote follow-up.
Only 1 study reported evaluating quality of life in patients followed up remotely at 3 and 6 months; no values were reported.
Patient satisfaction was evaluated in 5 cohort studies, all in short term follow-up: 1 for the Home Monitoring® RMS, 3 for the Care Link® RMS, and 1 for the House Call 11® RMS.
– Patients reported receiving a sense of security from the transmitter, a good relationship with nurses and physicians, positive implications for their health, and satisfaction with RM and organization of services.
– Although patients reported that the system was easy to implement and required less than 10 minutes to transmit information, a variable proportion of patients (range, 9% 39%) reported that they needed the assistance of a caregiver for their transmission.
– The majority of patients would recommend RM to other ICD patients.
– Patients with hearing or other physical or mental conditions hindering the use of the system were excluded from studies, but the frequency of this was not reported.
Physician satisfaction was evaluated in 3 studies, all with the Care Link® RMS:
– Physicians reported an ease of use and high satisfaction with a generally short-term use of the RMS.
– Physicians reported being able to address the problems in unscheduled patient transmissions or physician initiated transmissions remotely, and were able to handle the majority of the troubleshooting calls remotely.
– Both nurses and physicians reported a high level of satisfaction with the web registry system.
2. Effectiveness of Remote Monitoring Systems in Heart Failure Patients for Cardiac Arrhythmia and Heart Failure Episodes
Remote follow-up of HF patients implanted with ICD or CRT devices, generally managed in specialized HF clinics, was evaluated in 3 cohort studies: 1 involved the Home Monitoring® RMS and 2 involved the Care Link® RMS. In these RMSs, in addition to the standard diagnostic features, the cardiac devices continuously assess other variables such as patient activity, mean heart rate, and heart rate variability. Intra-thoracic impedance, a proxy measure for lung fluid overload, was also measured in the Care Link® studies. The overall diagnostic performance of these measures cannot be evaluated, as the information was not reported for patients who did not experience intra-thoracic impedance threshold crossings or did not undergo interventions. The trial results involved descriptive information on transmissions and alerts in patients experiencing high morbidity and hospitalization in the short study periods.
3. Comparative Effectiveness of Remote Monitoring Systems for CIEDs
Seven RCTs were identified evaluating RMSs for CIEDs: 2 were for PMs (1276 patients) and 5 were for ICD/CRT devices (3733 patients). Studies performed in the clinical setting in the United States involved both the Care Link® RMS and the Home Monitoring® RMS, whereas all studies performed in European countries involved only the Home Monitoring® RMS.
3A. Randomized Controlled Trials of Remote Monitoring Systems for Pacemakers
Two trials, both multicenter RCTs, were conducted in different countries with different RMSs and study objectives. The PREFER trial was a large trial (897 patients) performed in the United States examining the ability of Care Link®, an Internet-based remote PM interrogation system, to detect clinically actionable events (CAEs) sooner than the current in-office follow-up supplemented with transtelephonic monitoring transmissions, a limited form of remote device interrogation. The trial results are summarized below:
In the 375-day mean follow-up, 382 patients were identified with at least 1 CAE—111 patients in the control arm and 271 in the remote arm.
The event rate detected per patient for every type of CAE, except for loss of atrial capture, was higher in the remote arm than the control arm.
The median time to first detection of CAEs (4.9 vs. 6.3 months) was significantly shorter in the RMS group compared to the control group (P < 0.0001).
Additionally, only 2% (3/190) of the CAEs in the control arm were detected during a transtelephonic monitoring transmission (the rest were detected at in-office follow-ups), whereas 66% (446/676) of the CAEs were detected during remote interrogation.
The second study, the OEDIPE trial, was a smaller trial (379 patients) performed in France evaluating the ability of the Home Monitoring® RMS to shorten PM post-operative hospitalization while preserving the safety of conventional management of longer hospital stays.
Implementation and operationalization of the RMS was reported to be successful in 91% (346/379) of the patients and represented 8144 transmissions.
In the RM group 6.5% of patients failed to send messages (10 due to improper use of the transmitter, 2 with unmanageable stress). Of the 172 patients transmitting, 108 patients sent a total of 167 warnings during the trial, with a greater proportion of warnings being attributed to medical rather than technical causes.
Forty percent had no warning message transmission and among these, 6 patients experienced a major adverse event and 1 patient experienced a non-major adverse event. Of the 6 patients having a major adverse event, 5 contacted their physician.
The mean medical reaction time was faster in the RM group (6.5 ± 7.6 days vs. 11.4 ± 11.6 days).
The mean duration of hospitalization was significantly shorter (P < 0.001) for the RM group than the control group (3.2 ± 3.2 days vs. 4.8 ± 3.7 days).
Quality of life estimates by the SF-36 questionnaire were similar for the 2 groups at 1-month follow-up.
3B. Randomized Controlled Trials Evaluating Remote Monitoring Systems for ICD or CRT Devices
The 5 studies evaluating the impact of RMSs with ICD/CRT devices were conducted in the United States and in European countries and involved 2 RMSs—Care Link® and Home Monitoring ®. The objectives of the trials varied and 3 of the trials were smaller pilot investigations.
The first of the smaller studies (151 patients) evaluated patient satisfaction, achievement of patient outcomes, and the cost-effectiveness of the Care Link® RMS compared to quarterly in-office device interrogations with 1-year follow-up.
Individual outcomes such as hospitalizations, emergency department visits, and unscheduled clinic visits were not significantly different between the study groups.
Except for a significantly higher detection of atrial fibrillation in the RM group, data on ICD detection and therapy were similar in the study groups.
Health-related quality of life evaluated by the EuroQoL at 6-month or 12-month follow-up was not different between study groups.
Patients were more satisfied with their ICD care in the clinic follow-up group than in the remote follow-up group at 6-month follow-up, but were equally satisfied at 12- month follow-up.
The second small pilot trial (20 patients) examined the impact of RM follow-up with the House Call 11® system on work schedules and cost savings in patients randomized to 2 study arms varying in the degree of remote follow-up.
The total time including device interrogation, transmission time, data analysis, and physician time required was significantly shorter for the RM follow-up group.
The in-clinic waiting time was eliminated for patients in the RM follow-up group.
The physician talk time was significantly reduced in the RM follow-up group (P < 0.05).
The time for the actual device interrogation did not differ in the study groups.
The third small trial (115 patients) examined the impact of RM with the Home Monitoring® system compared to scheduled trimonthly in-clinic visits on the number of unplanned visits, total costs, health-related quality of life (SF-36), and overall mortality.
There was a 63.2% reduction in in-office visits in the RM group.
Hospitalizations or overall mortality (values not stated) were not significantly different between the study groups.
Patient-induced visits were higher in the RM group than the in-clinic follow-up group.
The TRUST Trial
The TRUST trial was a large multicenter RCT conducted at 102 centers in the United States involving the Home Monitoring® RMS for ICD devices for 1450 patients. The primary objectives of the trial were to determine if remote follow-up could be safely substituted for in-office clinic follow-up (3 in-office visits replaced) and still enable earlier physician detection of clinically actionable events.
Adherence to the protocol follow-up schedule was significantly higher in the RM group than the in-office follow-up group (93.5% vs. 88.7%, P < 0.001).
Actionability of trimonthly scheduled checks was low (6.6%) in both study groups. Overall, actionable causes were reprogramming (76.2%), medication changes (24.8%), and lead/system revisions (4%), and these were not different between the 2 study groups.
The overall mean number of in-clinic and hospital visits was significantly lower in the RM group than the in-office follow-up group (2.1 per patient-year vs. 3.8 per patient-year, P < 0.001), representing a 45% visit reduction at 12 months.
The median time from onset of first arrhythmia to physician evaluation was significantly shorter (P < 0.001) in the RM group than in the in-office follow-up group for all arrhythmias (1 day vs. 35.5 days).
The median time to detect clinically asymptomatic arrhythmia events—atrial fibrillation (AF), ventricular fibrillation (VF), ventricular tachycardia (VT), and supra-ventricular tachycardia (SVT)—was also significantly shorter (P < 0.001) in the RM group compared to the in-office follow-up group (1 day vs. 41.5 days) and was significantly quicker for each of the clinical arrhythmia events—AF (5.5 days vs. 40 days), VT (1 day vs. 28 days), VF (1 day vs. 36 days), and SVT (2 days vs. 39 days).
System-related problems occurred infrequently in both groups—in 1.5% of patients (14/908) in the RM group and in 0.7% of patients (3/432) in the in-office follow-up group.
The overall adverse event rate over 12 months was not significantly different between the 2 groups and individual adverse events were also not significantly different between the RM group and the in-office follow-up group: death (3.4% vs. 4.9%), stroke (0.3% vs. 1.2%), and surgical intervention (6.6% vs. 4.9%), respectively.
The 12-month cumulative survival was 96.4% (95% confidence interval [CI], 95.5%–97.6%) in the RM group and 94.2% (95% confidence interval [CI], 91.8%–96.6%) in the in-office follow-up group, and was not significantly different between the 2 groups (P = 0.174).
The CONNECT Trial
The CONNECT trial, another major multicenter RCT, involved the Care Link® RMS for ICD/CRT devices in a15-month follow-up study of 1,997 patients at 133 sites in the United States. The primary objective of the trial was to determine whether automatically transmitted physician alerts decreased the time from the occurrence of clinically relevant events to medical decisions. The trial results are summarized below:
Of the 575 clinical alerts sent in the study, 246 did not trigger an automatic physician alert. Transmission failures were related to technical issues such as the alert not being programmed or not being reset, and/or a variety of patient factors such as not being at home and the monitor not being plugged in or set up.
The overall mean time from the clinically relevant event to the clinical decision was significantly shorter (P < 0.001) by 17.4 days in the remote follow-up group (4.6 days for 172 patients) than the in-office follow-up group (22 days for 145 patients).
– The median time to a clinical decision was shorter in the remote follow-up group than in the in-office follow-up group for an AT/AF burden greater than or equal to 12 hours (3 days vs. 24 days) and a fast VF rate greater than or equal to 120 beats per minute (4 days vs. 23 days).
Although infrequent, similar low numbers of events involving low battery and VF detection/therapy turned off were noted in both groups. More alerts, however, were noted for out-of-range lead impedance in the RM group (18 vs. 6 patients), and the time to detect these critical events was significantly shorter in the RM group (same day vs. 17 days).
Total in-office clinic visits were reduced by 38% from 6.27 visits per patient-year in the in-office follow-up group to 3.29 visits per patient-year in the remote follow-up group.
Health care utilization visits (N = 6,227) that included cardiovascular-related hospitalization, emergency department visits, and unscheduled clinic visits were not significantly higher in the remote follow-up group.
The overall mean length of hospitalization was significantly shorter (P = 0.002) for those in the remote follow-up group (3.3 days vs. 4.0 days) and was shorter both for patients with ICD (3.0 days vs. 3.6 days) and CRT (3.8 days vs. 4.7 days) implants.
The mortality rate between the study arms was not significantly different between the follow-up groups for the ICDs (P = 0.31) or the CRT devices with defribillator (P = 0.46).
Conclusions
There is limited clinical trial information on the effectiveness of RMSs for PMs. However, for RMSs for ICD devices, multiple cohort studies and 2 large multicenter RCTs demonstrated feasibility and significant reductions in in-office clinic follow-ups with RMSs in the first year post implantation. The detection rates of clinically significant events (and asymptomatic events) were higher, and the time to a clinical decision for these events was significantly shorter, in the remote follow-up groups than in the in-office follow-up groups. The earlier detection of clinical events in the remote follow-up groups, however, was not associated with lower morbidity or mortality rates in the 1-year follow-up. The substitution of almost all the first year in-office clinic follow-ups with RM was also not associated with an increased health care utilization such as emergency department visits or hospitalizations.
The follow-up in the trials was generally short-term, up to 1 year, and was a more limited assessment of potential longer term device/lead integrity complications or issues. None of the studies compared the different RMSs, particularly the different RMSs involving patient-scheduled transmissions or automatic transmissions. Patients’ acceptance of and satisfaction with RM were reported to be high, but the impact of RM on patients’ health-related quality of life, particularly the psychological aspects, was not evaluated thoroughly. Patients who are not technologically competent, having hearing or other physical/mental impairments, were identified as potentially disadvantaged with remote surveillance. Cohort studies consistently identified subgroups of patients who preferred in-office follow-up. The evaluation of costs and workflow impact to the health care system were evaluated in European or American clinical settings, and only in a limited way.
Internet-based device-assisted RMSs involve a new approach to monitoring patients, their disease progression, and their CIEDs. Remote monitoring also has the potential to improve the current postmarket surveillance systems of evolving CIEDs and their ongoing hardware and software modifications. At this point, however, there is insufficient information to evaluate the overall impact to the health care system, although the time saving and convenience to patients and physicians associated with a substitution of in-office follow-up by RM is more certain. The broader issues surrounding infrastructure, impacts on existing clinical care systems, and regulatory concerns need to be considered for the implementation of Internet-based RMSs in jurisdictions involving different clinical practices.
PMCID: PMC3377571  PMID: 23074419
13.  Pre-Dialysis Systolic Blood Pressure-Variability Is Independently Associated with All-Cause Mortality in Incident Haemodialysis Patients 
PLoS ONE  2014;9(1):e86514.
Systolic blood pressure variability is an independent risk factor for mortality and cardiovascular events. Standard measures of blood pressure predict outcome poorly in haemodialysis patients. We investigated whether systolic blood pressure variability was associated with mortality in incident haemodialysis patients. We performed a longitudinal observational study of patients commencing haemodialysis between 2005 and 2011 in East Anglia, UK, excluding patients with cardiovascular events within 6 months of starting haemodialysis. The main exposure was variability independent of the mean (VIM) of systolic blood pressure from short-gap, pre-dialysis blood pressure readings between 3 and 6 months after commencing haemodialysis, and the outcome was all-cause mortality. Of 203 patients, 37 (18.2%) patients died during a mean follow-up of 2.0 (SD 1.3) years. The age and sex-adjusted hazard ratio (HR) for mortality was 1.09 (95% confidence interval (CI) 1.02–1.17) for a one-unit increase of VIM. This was not altered by adjustment for diabetes, prior cardiovascular disease and mean systolic blood pressure (HR 1.09, 95% CI 1.02–1.16). Patients with VIM of systolic blood pressure above the median were 2.4 (95% CI 1.17–4.74) times more likely to die during follow-up than those below the median. Results were similar for all measures of blood pressure variability and further adjustment for type of dialysis access, use of antihypertensives and absolute or variability of fluid intake did not alter these findings. Diastolic blood pressure variability showed no association with all cause mortality. Our study shows that variability of systolic blood pressure is a strong and independent predictor of all-cause mortality in incident haemodialysis patients. Further research is needed to understand the mechanism as this may form a therapeutic target or focus for management.
doi:10.1371/journal.pone.0086514
PMCID: PMC3904871  PMID: 24489735
14.  Cystatin C and Sudden Cardiac Death Risk in the Elderly 
Background
Recent studies have demonstrated an association between moderate kidney dysfunction and sudden cardiac death in people with cardiovascular disease.
Methods and Results
The study was a longitudinal analysis among 4465 participants from the Cardiovascular Health Study without prevalent cardiovascular disease at baseline. Cystatin C and creatinine were measured from baseline sera. SCD was defined as a sudden pulseless condition from a cardiac origin in a previously stable individual that occurred out of the hospital or in the emergency room. The association between cystatin C tertiles and SCD was determined with multivariate Cox proportional hazards. A similar analysis compared SCD incidence across creatinine-based eGFR tertiles. Over a median follow-up of 11.2 years, 91 adjudicated SCD events occurred. The annual incidence of SCD events increased across cystatin C tertiles: 10 events per 10,000 person years in tertile 1, 25 events per 10,000 person years in tertile 2 and 32 events per 10,000 person years in the highest cystatin C tertile. These associations persisted after multivariate adjustment: [HR = 2.72, 95% CI (1.44–5.16) in tertile 2 and HR = 2.67, 95% CI (1.33–5.35) in tertile 3]. After multivariate adjustment, the rate of SCD also increased in a linear distribution across creatinine-based eGFR tertiles: 15 events per 10,000 person years in tertile 1, 22 events per 10,000 person years in tertile 2 and 27 events per 10,000 person years in tertile 3. No significant associations, however, remained between creatinine-based eGFR and SCD after multivariable adjustment.
Conclusion
Impaired kidney function, as measured by cystatin C, has an independent association with SCD risk among elderly persons without clinical cardiovascular disease.
doi:10.1161/CIRCOUTCOMES.109.875369
PMCID: PMC2871673  PMID: 20233980
Cystatin C; kidney; sudden cardiac death; epidemiology
15.  Impact of Implantable Cardioverter-Defibrillator, Amiodarone, and Placebo on the Mode of Death in Stable Patients With Heart Failure 
Circulation  2009;120(22):2170-2176.
Background
The Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) demonstrated that implantable cardioverterdefibrillator (ICD) therapy reduces all-cause mortality in patients with New York Heart Association class II/III heart failure and a left ventricular ejection fraction ≤35% on optimal medical therapy. Whether ICD therapy reduced sudden death caused by ventricular tachyarrhythmias without affecting heart failure deaths in this population is unknown.
Methods and Results
SCD-HeFT randomized 2521 subjects to placebo, amiodarone, or shock-only, single-lead ICD therapy. Over a median follow-up of 45.5 months, a total of 666 deaths occurred, which were reviewed by an Events Committee and initially categorized as cardiac or noncardiac. Cardiac deaths were further adjudicated as resulting from sudden death presumed to be ventricular tachyarrhythmic, bradyarrhythmia, heart failure, or other cardiac causes. ICD therapy significantly reduced cardiac mortality compared with placebo (adjusted hazard ratio, 0.76; 95% confidence interval, 0.60 to 0.95) and tachyarrhythmia mortality (adjusted hazard ratio, 0.40; 95% confidence interval, 0.27 to 0.59) and had no impact on mortality resulting from heart failure or noncardiac causes. The cardiac and tachyarrhythmia mortality reductions were evident in subjects with New York Heart Association class II but not in subjects with class III heart failure. The reduction in tachyarrhythmia mortality with ICD therapy was similar in subjects with ischemic and nonischemic disease. Compared with placebo, amiodarone had no significant effect on any mode of death.
Conclusions
ICD therapy reduced cardiac mortality and sudden death presumed to be ventricular tachyarrhythmic in SCD-HeFT and had no effect on heart failure mortality. Amiodarone had no effect on all-cause mortality or its cause-specific components, except an increase in non-cardiac mortality in class III patients.
doi:10.1161/CIRCULATIONAHA.109.853689
PMCID: PMC2922511  PMID: 19917887
cardiomyopathy; death, sudden; heart failure; mortality; tachyarrhythmias
16.  Fish Oil in Primary and Secondary Cardiovascular Prevention 
The Ochsner Journal  2008;8(2):49-60.
Omega-3 fatty acid therapy shows great promise in both primary and secondary prevention of cardiovascular (CV) diseases, especially coronary heart disease (CHD). In this review, we discuss the evidence available from prospective and retrospective observational epidemiologic studies and controlled clinical trials demonstrating the effects of omega-3 fatty acids (fish oil) in primary and especially secondary prevention of major CV events, including CV mortality, fatal and nonfatal myocardial infarction (MI), and sudden cardiac death (SCD). Significant reductions in total mortality and SCD to the extent of 20% to 50% have been found in studies using doses ranging from 0.85 to 4.0 g/d. We review the compelling evidence that indicates all clinicians should strongly consider therapy with fish oil, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), for patients with known CV disease and for patients at increased risk for CV disease, particularly patients at increased risk for SCD. The target DHA + EPA consumption levels are about 800 to 1000 mg/d for individuals with known CHD and at least 500 mg/d for individuals without disease.
PMCID: PMC3096360  PMID: 21603485
Coronary heart disease prevention; DHA; docosahexaenoic acid; eicosapentaenoic acid; EPA; fish oil; omega-3 fatty acids
17.  Sudden Cardiac Death in Patients with Human Immunodeficiency Virus Infection 
Objectives
We sought to determine the incidence and clinical characteristics of sudden cardiac death (SCD) in patients with HIV.
Background
As the HIV-infected population ages, cardiovascular disease prevalence and mortality are increasing; however, the incidence and features of SCD have not yet been described.
Methods
Records of 2860 consecutive patients in a public HIV clinic in San Francisco, CA between April 2000 and August 2009 were examined. Identification of deaths, causes of death, and clinical characteristics were obtained by search of the National Death Index and/or clinic records. SCDs were determined using published retrospective criteria: (1) ICD10 code for all cardiac causes of death and (2) circumstances of death meeting WHO criteria.
Results
Of 230 deaths over 3.7 median years’ follow-up, 30 (13%) met SCD criteria, 131 (57%) were due to AIDS, 25 (11%) other (natural) diseases, and 44 (19%) overdose/suicides/unknown. SCDs accounted for 86% (30/35) of all cardiac deaths. The mean SCD rate was 2.6 per 1,000 person-years (95%CI 1.8-3.8), 4.5-fold higher than expected. SCDs occurred in older patients than AIDS deaths (mean 49.0 vs. 44.9 years, p=0.02). Compared to AIDS and natural deaths combined, SCDs had higher prevalence of prior MI (17% vs. 1%, p<0.0005), cardiomyopathy (23% vs. 3%, p<0.0005), heart failure (30% vs. 9%, p=0.004), and arrhythmias (20% vs. 3%, p=0.003).
Conclusions
SCDs account for most cardiac and many non-AIDS natural deaths in HIV-infected patients. Further investigation is needed to ascertain underlying mechanisms, which may include inflammation, antiretroviral therapy interruption, and concomitant medications.
doi:10.1016/j.jacc.2012.02.024
PMCID: PMC3356565  PMID: 22595409
AIDS; death, sudden; arrhythmia
18.  Strategies for the prevention and treatment of sudden cardiac death 
Cardiovascular diseases account for 40% of all deaths in the West. Sudden cardiac death (SCD) is a major health problem affecting over 300,000 patients annually in the United States alone. Presence of coronary artery disease (CAD), usually in the setting of diminished left ventricular ejection fraction, is still the single major risk factor for SCD. Additionally, acute myocardial ischemia, structural cardiac defects, anomalous coronary arteries, cardiomyopathies, genetic mutations, and ventricular arrhythmias are all attributed to SCD, demonstrating the perplexity of this condition. With the recent advancements in cardiovascular medicine, the incidence of SCD is expected to increase steeply as the prevalence of CAD and heart failure is uprising in general population. Considering SCD, the major challenge confronting contemporary cardiology, multiple strategies for prevention against SCD have been developed. β-blockers have been shown to reduce the risk of SCD, whereas implantable cardioverter–defibrillator devices are found to be effective at terminating the malignant arrhythmias. In recent years, multiple clinical trials were carried out to identify patients who may benefit from preventive intervention, including medical therapy and automatic cardioverter–defibrillator implantations. This review article provides insight into the advanced strategies for the prevention and treatment of SCD based on the data available in medical literature to date.
doi:10.2147/OAEM.S6869
PMCID: PMC3219585  PMID: 22102788
risk stratification; sudden cardiac death; prevention; treatment
19.  Prevention of sudden cardiac death in patients with chronic kidney disease 
BMC Nephrology  2012;13:162.
Cardiovascular deaths account for about 40% of all deaths of patients with chronic kidney disease (CKD), particularly those on dialysis, while sudden cardiac death (SCD) might be responsible for as many as 60% of SCD in patients undergoing dialysis. Studies have demonstrated a number of factors occurring in hemodialysis (HD) that could lead to cardiac arrhythmias. Patients with CKD undergoing HD are at high risk of ventricular arrhythmia and SCD since changes associated with renal failure and hemodialysis-related disorders overlap. Antiarrhythmic therapy is much more difficult in patients with CKD, but the general principles are similar to those in patients with normal renal function - at first, the cause of arrhythmias should be found and eliminated. Also the choice of therapy is narrowed due to the altered pharmacokinetics of many drugs resulting from renal failure, neurotoxicity of certain drugs and their complex interactions. Cardiac pacing in elderly patients is a common method of treatment. Assessment of patients’ prognosis is important when deciding whether to implant complex devices. There are reports concerning greater risk of surgical complications, which depends also on the extent of the surgical site. The decision concerning implantation of a pacing system in patients with CKD should be made on the basis of individual assessment of the patient.
doi:10.1186/1471-2369-13-162
PMCID: PMC3519551  PMID: 23206758
Arrhythmias; Chronic kidney disease; Renal failure; Sudden cardiac death
20.  Genetic Basis of Ventricular Arrhythmias 
Sudden cardiac death (SCD) is a leading cause of total and cardiovascular mortality, and ventricular fibrillation is the underlying arrhythmia in the majority of cases. In the young, where the incidence of SCD is low, a great proportion of SCDs occur in the context of inherited disorders such as cardiomyopathy or primary electrical disease, where a monogenic hereditary component is a strong determinant of risk. Marked advancement has been made over the past 15 years in the understanding of the genetic basis of the primary electrical disorders, and this has had an enormous impact on the management of these patients. At older ages, the great majority of SCDs occur in the context of acute myocardial ischemia and infarction. Although epidemiologic studies have shown that heritable factors also determine risk in these cases, inheritance is likely complex and multifactorial, and progress in understanding the genetic and molecular mechanisms that determine susceptibility to these arrhythmias, affecting a greater proportion of the population, has been very limited. We review the most recent insights gained into the genetic basis of both the monogenic and the more complex ventricular arrhythmias.
doi:10.1007/s12170-010-0128-2
PMCID: PMC2941045  PMID: 20936162
Genetics; Genetic polymorphisms; Genome-wide association study; Mutation; Cardiac arrhythmias; Ventricular fibrillation; Sudden cardiac death
21.  Aortic Valve Calcium Independently Predicts Coronary and Cardiovascular Events in a Primary Prevention Population 
Jacc. Cardiovascular Imaging  2012;5(6):619-625.
Objective
This study aimed to test whether aortic valve calcium (AVC) is independently associated with coronary and cardiovascular events in a primary-prevention population.
Background
Aortic sclerosis is associated with increased cardiovascular morbidity and mortality among the elderly, but the mechanisms underlying this association remain controversial and it is unknown if this association extends to younger individuals.
Methods
We performed a prospective analysis of 6,685 participants in the Multi-Ethnic Study of Atherosclerosis. All subjects, aged 45-84 years and free of clinical cardiovascular disease at baseline, underwent computed tomography for AVC and coronary artery calcium (CAC) scoring. The primary, pre-specified combined endpoint of cardiovascular events included myocardial infarctions, fatal and non-fatal strokes, resuscitated cardiac arrest and cardiovascular death, while a secondary combined endpoint of coronary events excluded strokes. The association between AVC and clinical events was assessed using Cox proportional hazards regression with incremental adjustments for demographics, cardiovascular risk factors, inflammatory biomarkers and subclinical coronary atherosclerosis.
Results
Over a median follow up of 5.8 [IQR 5.6, 5.9] years, adjusting for demographics and cardiovascular risk factors, subjects with AVC (n=894, 13.4%) had higher risks of cardiovascular (HR, 1.50; 95% CI, 1.10-2.03) and coronary (HR, 1.72; 95% CI, 1.19-2.49) events compared to those without AVC. Adjustments for inflammatory biomarkers did not alter these associations, but adjustment for CAC substantially attenuated both cardiovascular (HR, 1.32; 95% CI: 0.98-1.78) and coronary (HR, 1.41; 95% CI, 0.98-2.02) event risk. AVC remained predictive of cardiovascular mortality even after full adjustment (HR, 2.51; 95% CI, 1.22-5.21).
Conclusions
In this multiethnic MESA cohort, free of clinical cardiovascular disease, AVC predicts cardiovascular and coronary event risk independent of traditional risk factors and inflammatory biomarkers, likely due to the strong correlation between AVC and subclinical atherosclerosis. The association of AVC with excess cardiovascular mortality beyond coronary atherosclerosis risk merits further investigation.
doi:10.1016/j.jcmg.2011.12.023
PMCID: PMC3376353  PMID: 22698532
22.  Genomics, heart failure and sudden cardiac death 
Heart failure reviews  2008;15(3):229-238.
Sudden cardiac death (SCD) is among the most common causes of death in developed countries throughout the world. Despite decreased overall cardiac mortality, SCD vrates appear to be increasing in concert with escalating global prevalence of coronary disease and heart failure, the two major conditions predisposing to SCD. This unfavorable trend is a consequence of our inability to identify those who will die suddenly from lethal ventricular arrhythmias and to develop effective therapies for all populations at risk. The known risk factors for SCD lack the predictive power needed to generate preventive strategies for the large number of fatal arrhythmic events that occur among lower-risk subsets of the population. Even among recognized high-risk subsets, prediction of SCD remains challenging. With the exception of the implantable cardioverter defibrillator (ICD) there are few effective strategies for the prevention and treatment of SCD. This article discusses the prospect of genomic science as an approach to the identification of patients at high-risk for SCD. While the final common pathway for SCD is malignant ventricular arrhythmias, there are many potential contributors, pathways, and mechanisms by which common genetic variants (polymorphisms) could affect initiation and propagation of life-threatening cardiac arrhythmias. Recent advances in genomic medicine now provide us with novel approaches to both identify candidate genes/pathways and relatively common polymorphisms which may predispose patients to increased risk for SCD. Improved understanding of the relationship between common polymorphisms and SCD will not only improve risk stratification such that ICDs can be targeted to those patients most likely to benefit from them but also provide new insight into the pathophysiology of SCD.
doi:10.1007/s10741-008-9095-9
PMCID: PMC2851840  PMID: 18437561
Sudden cardiac death; Genomics; Heart failure; Single nucleotide polymorphisms
23.  Cardiovascular safety with linagliptin in patients with type 2 diabetes mellitus: a pre-specified, prospective, and adjudicated meta-analysis of a phase 3 programme 
Background
This study investigated the cardiovascular (CV) safety profile of the dipeptidyl peptidase (DPP)-4 inhibitor linagliptin versus comparator treatments.
Methods
This was a pre-specified meta-analysis of CV events in linagliptin or comparator-treated patients with type 2 diabetes mellitus (T2DM) from eight Phase 3 studies. All suspected CV events were prospectively adjudicated by a blinded independent expert committee. The primary endpoint was a composite of CV death, stroke, myocardial infarction, and hospitalization for unstable angina. Three secondary composite endpoints derived from the adjudicated CV events were also pre-specified. Risk estimates were calculated using several statistical methods including Cox regression analysis.
Results
Of 5239 treated patients (mean ± SD HbA1c 65 ± 10 mmol/mol [8.0 ± 0.9%], age 58 ± 10 years, BMI 29 ± 5 kg/m2), 3319 received linagliptin once daily (5 mg, 3159; 10 mg, 160) and 1920 received comparators (placebo, 977; glimepiride 1-4 mg, 781; voglibose 0.6 mg, 162). Cumulative exposure (patient-years) was 2060 for linagliptin and 1372 for comparators. Primary CV events occurred in 11 (0.3%) patients receiving linagliptin and 23 (1.2%) receiving comparators. The hazard ratio (HR) for the primary endpoint showed significantly lower risk with linagliptin than comparators (HR 0.34 [95% confidence interval (CI) 0.16-0.70]) as did estimates for all secondary endpoints (HR ranging from 0.34 to 0.55 [all upper 95% CIs < 1.0]).
Conclusions
These results from a large Phase 3 programme support the hypothesis that linagliptin may have CV benefits in patients with T2DM.
doi:10.1186/1475-2840-11-3
PMCID: PMC3286367  PMID: 22234149
Cardiovascular risk; DPP-4 inhibitor; linagliptin; meta-analysis; type 2 diabetes mellitus
24.  Echocardiographic assessment of left atrial size in patients with end-stage renal disease 
Cardiovascular Journal of Africa  2009;20(3):183-186.
Background
Cardiac disease is the most common cause of death in patients with end-stage renal disease. It is assumed that the high rate of cardiovascular mortality is related to accelerated atherosclerosis. Patients with chronic renal insufficiency have an increased prevalence of coronary artery disease, silent myocardial ischaemia, complex ventricular arrhythmias, atrial fibrillation, left ventricular hypertrophy, annular mitral and aortic valve calcification, and enlargement of the left atrium, than patients with normal renal function. It is also well known that haemodialysis is associated with cardiovascular structural changes and rapid fluctuations in electrolyte levels.
In this study, we sought to estimate left atrial size by means of echocardiography and to determine any correlations between different echocardiographic measurements in patients with end-stage renal disease.
Methods
We analysed data from 123 patients who were on regular haemodialysis, by means of traditional transthoracic echocardiographic examination. The usual statistical parameters, correlations and the Student’s t-test were performed, with levels of significance of p < 0.01 and p < 0.05.
Results
The most presented age group was 60 to 69 years old, with a predomination of females (56.1%). We found dilated left atrium in 26.02% of the study patients and a high statistical correlation between different methods of measurement and calculated volumes of the left atrium.
Conclusion
Evaluation of left atrial size should be determined by several different measurements, and left atrial enlargement should be seen as a risk factor for advancing disease.
PMCID: PMC3721427  PMID: 19575083
25.  VITAMIN D, PARATHYROID HORMONE, AND CARDIOVASCULAR EVENTS AMONG OLDER ADULTS 
Background
Vitamin D deficiency and parathyroid hormone (PTH) excess are common among older adults and may adversely impact cardiovascular health. We evaluated associations of 25-hydroxyvitamin D (25-OHD) and PTH concentrations, separately, and in combination, with incident cardiovascular events and mortality during 14 years of follow-up in the Cardiovascular Health Study.
Methods and results
We studied 2,312 participants who were free of cardiovascular disease at baseline. We measured 25-OHD and intact PTH from previously frozen serum using mass spectrometry and a two-site immunoassay. Outcomes were adjudicated cases of myocardial infarction, heart failure, cardiovascular death, and all cause mortality. There were 384 participants (17%) who had serum 25-OHD concentrations <15 ng/ml and 570 (25%) who had serum PTH concentrations ≥ 65 pg/ml. After adjustment, each 10-ng/ml lower 25-OHD concentration was associated with a 9% greater (95% CI 2% to 17% greater) relative hazard of mortality and a 25% greater (95% CI 8% to 44% greater) relative hazard of myocardial infarction. Serum 25-OHD concentrations <15 ng/ml, were associated with a 29% greater (95% CI 5% to 55% greater) risk of mortality. Serum PTH concentrations ≥ 65 pg/ml were associated with a 30% greater risk of heart failure (95% CI 6% to 61% greater), but not other outcomes. There was no evidence of an interaction between serum 25-OHD and PTH concentrations and cardiovascular events.
Conclusions
Among older adults, 25-OHD deficiency is associated with myocardial infarction and mortality; PTH excess is associated with heart failure. Vitamin D and PTH might influence cardiovascular risk through divergent pathways.
doi:10.1016/j.jacc.2011.03.069
PMCID: PMC3210558  PMID: 21939825
Vitamin D; parathyroid hormone; myocardial infarction; cardiovascular death; heart failure; mortality; mineral metabolism

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