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1.  A Study of Unusual Pacemaker Infection by Mycobacterium Tuberculosis in Indian Patients 
The expanding clinical indications of cardiac rhythm management have led to an increased use of pacemaker implantation which is associated with increased incidence of pacemaker infections. Staphylococcus aureus and epidermidis account for the vast majority of pacemaker infections. Pacemaker infection due to Mycobacterium tuberculosis (M. tuberculosis) is very rare, only few cases having been reported till date.
We describe here a study of three patients of pacemaker pocket infection with M. tuberculosis.
The possibility of mycobacterial pacemaker infection should always be kept in mind in patients with delayed pacemaker infection.
PMCID: PMC4267925  PMID: 25568594
Mycobacterium tuberculosis; Pacemaker Infection
2.  Successful Ablation of Cavotricuspid Isthmus-dependent Atrial Flutter Guided by Contact Force Vector in a Patient After a Tricuspid Valve Replacement 
A 46-year-old man after a tricuspid valve replacement due to traumatic severe tricuspid regurgitation developed cavotricuspid isthmus-dependent counterclockwise atrial flutter. During a linear ablation using a contact force-sensing irrigated ablation catheter, the flutter could be terminated by a radiofrequency application within a deep pouch just below the bioprosthetic tricuspid valve.
PMCID: PMC4286955  PMID: 25609899
Cavotricuspid isthmus-dependent atrial flutter; Contact force vector; Tricuspid valve replacement; Catheter ablation
3.  Fragmented QRS and Chagas' disease 
PMCID: PMC4286949  PMID: 25609900
Fragmented QRS; Chagas' disease
4.  Infections of Cardiac Implantable Electronic Devices 
PMCID: PMC4286950  PMID: 25609894
Cardiac Implantable Electronic Devices; Infections
5.  Freezing at the His Bundle 
PMCID: PMC4286951  PMID: 25609895
His bundle; cryoablation
6.  Shoulder Joint Dislocation as an Unusual Complication of Defibrillation Threshold Testing Following Subcutaneous Implantable Cardioverter-Defibrillator Implantation 
A 53-year-old man underwent implantation of a totally subcutaneous ICD (S-ICD; Boston Scientific). He was positioned supine, with the left arm abducted, externally rotated (i.e. palm up) and strapped to the arm extender. The generator was placed in the left mid-axillary line along the 5th-6th intercostal spaces and the defibrillation coil was tunneled anterior to the sternum. Defibrillation threshold (DFT) testing with 65 Jcaused a forceful pectoralis twitch. The patient woke up with a painful anteriorly dislocated left shoulder. Glenohumeral dislocation due to DFT testing has not been previously reported. It is likely that this complication is specific to the S-ICD implantation, and is related to positioning with the arm abducted, externally rotated, and immobilized, and use of greater defibrillation energy with current pathway through the bulk of the pectoralis muscle.Precautions may include extending the arm palm down, strapping the arm loosely, and adduction of the arm for DFT testing.
PMCID: PMC4286953  PMID: 25609897
Subcutaneous implantable cardioverter-defibrillator; defibrillation threshold testing; shoulder dislocation; complication; device implantation
7.  Sustained Ventricular Tachycardia In An Apparently Healthy Heart: A Very Localized Left Dominant Arrhythmogenic Cardiomyopathy 
A 62-year-old man admitted for presyncope presented two symptomatic sustained ventricular tachycardia with right bundle branch morphology and inferior axis suggesting a pathology of the left ventricular lateral wall, the site where Cardiac Magnetic Resonance demonstrated a thinned, hypokinetic segment with fibro-fatty subepicardial infiltration. A very localized Left Dominant Arrhythmogenic Cardiomyopathy was diagnosed and an ICD implanted.
PMCID: PMC4286954  PMID: 25609898
Arrhythmogenic Cardiomyopathy; Ventricular Tachycardia; Cardiac Magnetic Resonance
9.  Strategies for Overcoming T-Wave Oversensing 
PMCID: PMC4286957  PMID: 25609902
T-Wave Oversensing
11.  Update on Ventricular Tachyarrhythmias and Related Sudden Cardiac Death 
PMCID: PMC4286959  PMID: 25609904
Ventricular Tachyarrhythmia; Sudden Cardiac Death
12.  Cryoablation of Anteroseptal Accessory Pathways with a His Bundle Electrogram on the Ablation Catheter 
Radiofrequency catheter ablations of anteroseptal (AS) accessory pathways (AP) in pediatric patients have higher incidence of atrioventricular (AV) block than other AP locations. We report our experience using cryoablation in pediatric patients where a His bundle electrogram was noted on the ablation catheter at the site of the successful ablation.
Methods and Results
We retrospectively reviewed all patients ≤21 years that underwent cryoablation for an AS AP from 2005 to 2012 at our institution (n=70). Patients with a His bundle electrogram noted on the cryoablation catheter at the location of the successful lesion were identified (n=6, 8.5%). All six patients had ventricular preexcitation. Median age of 15.9 years (7.2 - 18.2). AV nodal function was monitored during the cryoablation with intermittent rapid atrial pacing conducted through the AV node (n=2), with atrial extra-stimulus testing (n=2), or during orthodromic reentrant tachycardia (n=2). Acute success occurred in all patients. Two patients had early recurrence of AP conduction. Both patients underwent a second successful cryoablation, again with a His bundle electrogram on the cryoablation catheter. At a median follow-up of 13 months (3 to 37 months) there was no recurrence of accessory pathway conduction and AVN function was normal.
In a small number of pediatric patients with AS AP with a His bundle electrogram seen on the ablation catheter, the use of cryotherapy was safe and effective for elimination of AP conduction without impairment of AV nodal conduction.
PMCID: PMC4286952  PMID: 25609896
Cryoablation; Anteroseptal Accessory Pathways
13.  Exchanging Catheters Over a Single Transseptal Sheath During Left Atrial Ablation is Associated with a Higher Risk for Silent Cerebral Events 
Silent cerebral events (SCE) have been identified on magnetic resonance imaging (MRI) in asymptomatic patients after atrial fibrillation (AF) ablation. Procedural determinants influencing the risk for SCE still remain unclear.
Comparing the risk for SCE depending on exchanges of catheters (ExCath) over a single transseptal sheath.
88 Patients undergoing pulmonary vein isolation (PVI) only ablation using either single-tip or balloon-based technique underwent pre- and post-ablation cerebral MRI. Ablations were either performed with double transseptal access and without exchanging catheters over the transseptal sheaths (group 1: no ExCath) or after a single transseptal access and exchanges of therapeutic and diagnostic catheters (group 2: ExCath). Differences in regard to SCE rates were analyzed. Multivariate analysis was performed to identify factors related to the risk for SCE.
Included patients underwent PVI using single tip irrigated radiofrequency in 41, endoscopic laser balloon in 27 and cryoballoon in 20 cases. Overall SCE were identified in 23 (26%) patients. In group 1 (no ExCath; N=46) 6 patients (13%) and in group 2 (N=42) 17 patients (40%) had documented SCE (p=0.007). The applied ablation technology did not affect SCE rate. In multivariate analysis age (OR 1.1, p=0.03) and catheter exchanges over a single transseptal sheath (OR 12.1, p=0.007) were the only independent predictors of a higher risk for SCE.
Exchanging catheters over a single transseptal access to perform left atrial ablation is associated with a significantly higher incidence of SCE compared to an ablation technique using different transseptal accesses for therapeutic and diagnostic catheters.
PMCID: PMC4217296  PMID: 25408564
Silent cerebral lesions; atrial fibrillation ablation; magnetic resonance imaging
14.  Differences in Quality of Life, Anxiety and Depression in Patients with Paroxysmal Atrial Fibrillation and Common Forms of Atrioventricular Reentry Supraventricular Tachycardias 
The aim of this study was to evaluate the differences in quality of life and psychosocial stress parameters among patients with paroxysmal atrial fibrillation (AF) and common forms of atrioventricular reentry supraventricular tachycardias (SVTs).
Methods and Results
The total study population included 106 patients, 54 patients with paroxysmal AF (32 males, age 56.64±12.50 years) and 52 with SVTs (25 males, age 40.46±14.96 years). General health (p<0.01), physical function (p=0.004), role emotion (p=0.002) and role physical (p<0.01) scores were lower in patients who suffered AF. SF-36 physical and mental health summary measures were also significantly lower in the AF group compared to those in SVT group (p<0.01 and p=0.001, respectively). Lower SF-36 total score was observed in patients with AF compared to those with SVTs (p<0.01). Comparing the anxiety and depression scores all the values were higher in patients with AF. Higher STAI-state scores (p<0.01), STAI-trait scores (p=0.039) and BDI scores (p=0.077) were seen in patients who suffered AF comparing to those with SVTs.
Quality of life is significantly impaired and the level of anxiety is significantly higher in patients with AF comparing to those with common forms of SVTs.
PMCID: PMC4217297  PMID: 25408565
Quality of life; anxiety; depression; supraventricular tachycardias; atrial fibrillation
16.  Electroanatomic Mapping-Guided Radiofrequency Ablation of Adenosine Sensitive Incessant Focal Atrial Tachycardia Originating from the Non-Coronary Aortic Cusp in a Child 
Incessant focal atrial tachycardia may be encountered in the pediatric age group although it is rarely seen. Ablation using radiofrequency or cryothermal energy is the preferred method for drug-resistant cases. Recently, 3D electroanatomic mapping systems have been increasingly used for mapping and ablation. In this report, we presented, for the first time, a pediatric case with incessant focal atrial tachycardia originating from the non-coronary aortic sinus and ablated using 3D electroanatomic mapping system.
PMCID: PMC4217299  PMID: 25408566
electroanatomic; focal; non-coronary cusp
17.  Catheter Ablation in Patients with Electrical Storm in Early Post Infarction Period (6 Weeks): A Single Centre Experience 
Electrical storm (ES) due to drug refractory ventricular tachycardia (VT) occurring within first few weeks of acute myocardial infarction (MI) has poor prognosis. Catheter ablation has been proposed for treating VT occurring late after MI, but there is limited data on catheter ablation in VT within first few weeks of MI.
Methods and Results
Five patients (4 males, mean age 54.2±12.11 years) between June 2008 to July 2012, referred for VT presenting as ES refractory to antiarrhythmic drugs in the early post infarction period (six weeks following MI) despite revascularization. Three patients had anterior wall MI and two inferior wall MI with left ventricular ejection fraction ranging from 26 to 35%.All underwent catheter ablation within 48 hours of being in VT except one who presented late. Clinical VT was induced in all five patients. Total number of VTs induced were 11 (2.2±1.09 per patient). Two patients needed epicardial ablation via pericardial puncture. Though acute success was 100%, one patient had recurrence of clinical VT the next day of procedure.One patient succumbed to sepsis with multiple organ failure. The remaining four patients are doing well without further clinical recurrence of VT over a period of 3.7 years of follow-up.
Catheter ablation can be a useful adjunctive therapy for patients with recurrent VT in the early post infarction period. This procedure appears to be safe with acceptable success rate.
PMCID: PMC4217300  PMID: 25408563
Electrical storm; Myocardial Infarction; Catheter Ablation
18.  Stress and Cardiac Arrhythmias 
PMCID: PMC4217301  PMID: 25408562
Stress; Cardiac Arrhythmias
20.  Never Out of the Woods: Onset of Events in Long QT Syndrome Late in Life Provoked by Atrial Arrhythmias 
The assessment of risk in the asymptomatic patient with long QT syndrome can often be a challenging task, particularly when the available evidence is limited to relatively small retrospective registries, not to mention the need to consider the effect of individual patient factors which are often difficult to quantitate. We describe the relatively uncommon case of a man with a long-standing diagnosis of Long QT 2 syndrome who suffered his first cardiac event in his late 60's, likely precipitated by the development of paroxysmal atrial tachycardia. A brief review of the available literature on risk assessment in adults with genetically confirmed long QT syndrome who have remained asymptomatic late into adulthood will follow the case.
PMCID: PMC4217303  PMID: 25408567
Long QT Syndrome; Atrial Arrhythmias
21.  Hemostasis of Left Atrial Appendage Bleed With Lariat Device 
New devices designed for minimally invasive closure of the left atrial appendage (LAA) may be a viable alternative for patients in whom anticoagulation is considered high risk. The Lariat (Sentreheart, Redwood City, CA), which is currently FDA-approved for percutaneous closure of tissue, requires both trans-septal puncture and epicardial access. However it requires no anticoagulation after the procedure. Here we describe a case of effusion and tamponade during a Lariat procedure with successful completion of the case and resolution of the effusion.
PMCID: PMC4217304  PMID: 25408569
Left Atrial Appendage; Lariat Device
22.  Cardiac Resynchronization Therapy in a Patient with Persistent Left Superior Vena Cava Draining into the Coronary Sinus and Absent Innominate Vein: A Case Report and Review of Literature 
Persistent left superior vena cava (PLSVC) is a rare congenital anomaly of the superior venous system that may be discovered at the time of cardiac implantable electronic device (CIED) implantation.
Methods and Results
We present a subject who needed cardiac resynchronization therapy (CRT)-CIED implantation and was discovered to have PLSVC with absent innominate vein during the implant procedure. We were able to successfully implant a CRT-CIED using a right-sided approach via the right superior vena cava (SVC). We present a description of our implant technique and a brief review of the different aspects of CIED implantation in subjects with variants of PLSVC.
Superior venous anomalies such as PLSVC can make CIED implantation technically challenging. However, with increasing operator experience, cardiac imaging and appropriate tools successful CIED implantation is possible in almost all cases.
PMCID: PMC4217305  PMID: 25408568
Cardiac Resynchronization Therapy; Persistent Left Superior Vena Cava; Coronary Sinus; Absent Innominate Vein
24.  Intermittent Right Ventricular Outflow Tract Capture due to Chronic Right Atrial Lead Dislodgement 
A 58 year old male, known case of type 2 diabetes and hypertension, had undergone implantation of a dual chamber pacemaker(DDDR) in 2007 for complaints of recurrent syncope and trifascicular block with a normal ejection fraction andnormal coronaries. His post implantation parameters were normal at that time.He now presented to our pacemaker clinic where his ECG done showed two types o fpaced complexes. The first few complexes were consistent with atrial sensed right ventricular apical pacing with left superior axis. Later complexes showed loss of atrial sensing with pacing from right ventricular outflow tract(inferior axis) with subtle oscillation in it's axis. On application of magnet, two pacemaker spikes were visible withinterspike interval of 120 ms and paced complexes with inferior axis starting from the first spike suggesting that the atrial lead was responsible for RVOT depolarization. On interrogation of the pacemaker, atrial EGM showed sensed activity from atrium followed by large sensed ventricular complex. Fluoroscopy confirmed that the atrial lead was dislodged and was intermittently prolapsing into the RVOT. Since the patient was asymptomatic, he refused any intervention and subsequentlyhis atrial lead was switched off by telemetry. The above case signifies that asymptomatic lead dislodgement is no talways manifested as loss of capture and even subtle variation of the axis o fthe paced complexes can provide us with a clue that can be confirmed by telemetry of the pacemaker and fluoroscopy.
PMCID: PMC4100087  PMID: 25057224
Dual chamber pacemaker; lead dislodgement; Electrogram (EGM)
25.  Repolarization Parameters Are Associated With Mortality In Chagas Disease Patients In The United States 
The goal of this study was to examine the association between ECG repolarization parameters and mortality in Chagas disease (CD) patients living in the United States.
CD patients with cardiomyopathy (CM) and bundle branch block (BBB) or BBB alone were compared to age- and sex-matched controls. QT interval, QT dispersion (QTd), T wave peak to T wave end duration (Tp-Te) and T wave peak to T wave end dispersion ((Tp-Te)d) were measured. Presence of fractionated QRS (fQRS) was also assessed. The main outcome measure was the association between ECG parameters and mortality or need for cardiac transplant.
A total of 18 CM and 13 BBB CD patients were studied with 97% originating from Mexico or Central America. QTd (60.0±15.0 ms vs 43.5±9.8 ms, P=0.0002), Tp-Te (102.6±29.3 ms vs 77.1±11.0 ms, P=0.0002) and (Tp-Te)d (39.5±9.4 ms vs 22.7±7.6 ms, P<0.0001) were prolonged in CD CM patients compared to CM controls. Chagas CM patients had more fQRS then controls (84.2±0.10% vs 33.3±0.11%, p=0.0005). QTd (59.9±15.0 ms vs 29.5±6.9 ms, P=0.0001) and (Tp-Te)d (40.0±15.9 ms vs 18.5±5.4 ms, p<0.0001) were longer in the CD BBB group compared to BBB controls. Univariate analysis showed QTd (56.9±15.0 ms vs 46.5±17.3 ms, p=0.0412) and (Tp-Te)d (36.8±13.5 ms vs 28.5±13.3 ms, p=0.0395) were associated with death and/or need for cardiac transplant.
Our results indicate that P-max and PD are useful electrocardiographic markers for identifying the β-TM-high-risk patients for AF onset, even when the cardiac function is conserved.
PMCID: PMC4100080  PMID: 25057218
Chagas Disease; Repolarization Parameters; Mortality

Results 1-25 (585)