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To report on the clinical presentation, etiology, and laboratory features of acute and chronic atrial fibrillation (AF) in a tertiary hospital in Riyadh, Saudi Arabia.
We retrospectively studied records of 720 patients with AF seen in outpatients and inpatients departments at King Abdulaziz Medical City, Riyadh, during the period of 1 January 2002 to 31 August 2008.
Documented acute and chronic AF was present in 157 (21.8%) and 563 (78.1%) patients, respectively. Palpitations, dizziness and syncope were the most frequent symptoms in acute AF, while dyspnea and palpitations were the most common symptoms in the chronic type. Acute respiratory problems and acute myocardial infarction were significantly more common in acute AF, while congestive heart failure and acute respiratory problems (chest infection, bronchial asthma, and pulmonary embolism) were significantly more common in chronic AF. The most common causes of both types of AF were diabetes mellitus (DM) in 68.8%, hypertension (HTN) in 59.3%, chronic lung diseases (bronchial asthma, chronic obstructive pulmonary disease and interstitial lung disease) in 31.8%, valvular heart disease in 23.6%, and ischemic heart disease (IHD) in 23.1%. In 9 (1.3%) patients, no cause was detected. The echocardiographic findings of left ventricular hypertrophy, valve lesions, and depressed left ventricular function were significantly more common in chronic AF (P<0.01).
Nowadays, DM, HTN, and IHD are becoming the most common predisposing factors for AF in the central region of Saudi Arabia and require prevention and control
Atrial fibrillation (AF) is the most common cardiac arrhythmia with a rising prevalence. In the United States, approximately 2.3 million people are currently diagnosed with AF and it is estimated that this prevalence may increase to 5.6 million by 2050, increasing healthcare resource utilization and costs, emergency department visits, hospital admissions, and mortality. AF is most frequently associated with ischemic heart disease (IHD), hypertension (HTN), and valvular heart disease, but in 10% of patients there may be no obvious underlying cause. It is associated with an increased risk of stroke, heart failure, and systemic emboli.
The prevalence of diabetes mellitus (DM), HTN, and IHD is on the increase in Saudi Arabia, while rheumatic heart disease (RHD) is still common. Thus, a large part of the population is at risk of developing AF. However, except for one previous study on AF from Southern Saudi Arabia in 1998, there is no recent local data on this most common cardiac arrhythmia. Identification of the presentations and major causes of both types of AF in the Saudi population may facilitate the prevention and proper management of this disease. The aim of this study was to report on the clinical presentation, underlying diseases, and relevant laboratory features of acute and chronic AF from a bigger sample from a tertiary care center in central Saudi Arabia to find out what differences there are from similar reports from other parts of the world. This may help to track any changes in underlying causes in future studies.
This was a retrospective, observational, cross-sectional study done at King Abdulaziz Medical City, Riyadh, which is a 750-bed teaching tertiary care hospital with a cardiology and cardiac surgery center and is one of the main referral health facilities in central Saudi Arabia. After obtaining the approval of the institutional research and ethical committee, the electronic and paper medical records of all consecutive patients visiting the medical and cardiology clinics or admitted to this hospital in medical, cardiology, or surgical wards with the primary diagnosis of AF based on ICD-9-CM Diagnosis Code 427.31 from January 1, 2002 to August 31, 2008 were retrieved. The records were reviewed without any exclusion criteria for demographic information, presenting symptoms and signs, thyroid function and other biochemical tests, including cardiac enzymes as indicated, chest x-ray reports, and echocardiography findings to assess the etiology and type of AF. Serial electrocardiograms (ECG) were reviewed for confirmation of AF and the presence of other abnormalities at the initial presentation and before starting any medication. AF was diagnosed when the ECG showed fibrillatory (f) waves of atrial activity with an irregular ventricular response. AF was grouped into acute and chronic. AF was considered acute when it was paroxysmal and lasted less than 7 days (with spontaneous termination or requiring urgent cardioversion to sinus rhythm because of poor tolerance); persistent when it lasted for more than 7 days up to 1 year; and permanent when it lasted for 1 year or more. However, the term “chronic” will be used for both types, i.e. persistent and permanent due to the retrospective nature of our study. The reported ECG and echocardiography findings were defined according to the standard criteria. Depressed left ventricular function was defined as echocardiographic finding of left ventricular ejection fraction of less than 40%. IHD was diagnosed according to the typical clinical presentation supported by relevant ECG and echocardiographic findings with elevated cardiac enzymes in cases with acute myocardial infarction. The data were analyzed by the Excel program. The chi-square test was calculated by MEDcal and t-test was applied for the comparison of quantitative data. A P-value of less than 0.05 was considered statistically significant.
Of the 720 cases with documented diagnosis of AF, 157 (21.8%) were acute, while 563 (78.1%) were chronic. Males were more commonly affected with acute AF, while females were more commonly affected with chronic AF. Table 1 summarizes the presenting symptoms, clinical findings, and acute complications. The main symptoms included dyspnea (59.3%), palpitations (24.5%), chest pain (13.4%), and dizziness, with or without syncope (6.25%). Palpitations and dizziness with or without syncope were significantly frequent in acute AF, while dyspnea alone was significantly more frequent in chronic AF. The most common clinical findings in both groups were heart failure (26.2%), acute embolic complications (7.9%), and acute respiratory problems (chest infection, bronchial asthma and pulmonary embolism) (29%). Heart failure and embolic complications were significantly higher in chronic AF compared with acute AF (P<0.01). The frequency of acute respiratory problems was the same in the two groups. Furthermore, 10.1% of all patients presented with acute myocardial infarction.
Table 2 summarizes the underlying diseases associated with AF. These included DM, HTN, chronic lung diseases (bronchial asthma, COPD, and interstitial lung diseases), IHD, and valvular heart disease (mitral and aortic valve or combined) as the most common causes. However, valvular heart disease was significantly more frequent in acute AF compared to chronic AF (P<0.001), while DM and HTN were more common in chronic AF. IHD was present in 33.1% and 20.4% of patients in acute and chronic AF, respectively (P=0.003). AF of unknown cause (lone AF) was present in 1.25% of all patients, but was more prevalent among patients with acute AF. Subclinical or overt hyperthyroidism was present in 41 (5.6%) patients. Idiopathic dilated cardiomyopathy, hypertrophic obstructive cardiomyopathy, Wolf Parkinson White (WPW) syndrome, chronic pericarditis, and alcohol abuse were less frequently encountered.
Table 3 summarizes the comparison of chest x-ray, ECG, and echocardiographic findings in acute and chronic AF. The ECG findings of left ventricular hypertrophy (LVH) were found in 81 (11.25%) patients P<0.0001 and were significantly more common in acute AF than in chronic AF (24.8% vs. 7.4%, P<0.0001). Ischemia, including changes of acute myocardial infarction, old myocardial infarction, or ischemic ST-segment and T-wave changes, was seen in 143 (19.8%) patients and was more common in acute AF than in chronic AF (3.8% vs. 24.3%, P<0.0001). Echocardiography was done for all patients. The most common abnormality was chamber dilation (dilation of one, two, or more chambers) in 70.5% of all patients, but was significantly more frequent in chronic AF (390 patients). Depressed left ventricular function and LVH were present in 197 (27.4 %) and 190 (26.3%) of patients respectively with no significant difference between acute and chronic AF.
This hospital-based retrospective study is the first one from Riyadh and to our knowledge, the second in Saudi Arabia. We found acute AF to be more common in males and chronic AF more common in females. The most common symptoms included dyspnea, palpitations, and chest pain, while the main clinical findings were congestive heart failure, acute myocardial infarction, and acute respiratory problems, stroke, transient ischemic attacks, limb ischemia alone, or in combination as the main acute complications. DM, HTN, IHD, and valvular heart disease were the main underlying causes but lone AF was rare.
In a previous study from southern Saudi Arabia, the main causes included rheumatic valvular disease, IHD, HTN, and lung diseases in 26%, 24%, 24%, and 13%, respectively compared to 24%, 23%, 59%, and 32% in our study, indicating that more of our patients had HTN and lung disease. With DM present in 68% of our patients, this indicates that these diseases are either more prevalent in this part of Saudi Arabia or have increased over the last 12 years. Lone AF was only present in 1% of our patients compared to 13% in the previous Saudi study. This may be related to more thorough investigations including echocardiography and thyroid functions at our center.
In our study, AF was more common in females than males. This is in contrast to Western studies where AF is more common in males than in females.[9–11] The main risk factors of DM, HTN, IHD in our study underscore the importance of these in the risk stratification for stroke in the CHADS2 scoring system.
DM which is reaching epidemic proportions in Saudi Arabia in affecting about 23% of population, is an important indirect risk factor for AF since it is associated with obesity and predisposes to HTN and IHD. DM also decreases the maintenance of sinus rhythm after successful electrical cardioversion in AF. Similarly, obesity is associated with an increased risk of AF due to left atrial dilatation.
Although hyperthyroidism was less common as a cause of AF in our study, it is an important reversible cause of AF and should be routinely checked as subclinical or overt hyperthyroidism increases the risk of AF as do thyroid function tests in the upper normal range.[16–18] Dilated or hypertrophic cardiomyopathy was an uncommon cause of AF in our study, which confirmed findings of previously published reports. Alcoholism was not an important cause of AF in our study.
Echocardiographic evidence of left ventricular (LV) dilatation, depressed LV function, and LVH were present in 71%, 27%, and 26% of AF patients, respectively, in our study. LVH was detected by ECG in a smaller number of these patients compared to echocardiography (11% vs. 26 %), indicating the superiority of the latter in the diagnosis of LVH. The risk of AF is increased by these changes, while it is decreased and improved with medications.[19–21]
Although this study is bigger than a previous Saudi study on AF (720 vs. 219 patients), we acknowledge the limitations of our study. Owing to its retrospective, cross-sectional nature, it was not always possible to classify AF into paroxysmal, persistent, and permanent because after 7 days it was not always clear whether AF terminated within 1 year or remained permanent. These two categories were therefore grouped as chronic. There is a need for bigger multicenter prospective studies to determine the changing trends in incidence, prevalence, risk factors, complications, and compliance to guidelines in the management of AF in different parts of Saudi Arabia. The categorization of AF into paroxysmal, persistent, and permanent can also be addressed in such a study.
In conclusion, we demonstrated the differences in presentation and the underlying causes between acute and chronic AF in our developing nation, which is witnessing a rise in the incidence of DM, HTN, and IHD, the most common predisposing factors for AF. Therefore, the control of these diseases, as well as the already existing high incidence of RHD, remains an important challenge to health authorities in Saudi Arabia. Community-based programs, such as intensive screening and health education will be required for primary prevention of these diseases.
Source of Support: Nil
Conflict of Interest: Nil