- Atrial fibrillation (AF) is the most common arrhythmia in adults and is associated with increased mortality and morbidity. To characterize patients diagnosed with AF in primary care clinics in southern Israel. We conducted a cross-sectional study in 14 primary care clinics of the largest health insurance fund in Israel, reviewing the electronic medical records of adults aged > or = 25 years diagnosed with AF. The prevalence, evaluation, antithrombotic treatment and treatments for rate control/rhythm control were analyzed. We retrieved the records of 995 patients with a diagnosis of AF; the prevalence of AF was 1.5% (2.5% aged > or = 45 years). The patients' mean age was 73.5 +/- 1.4 years and 55.3% were female. Vitamin K antagonist (VKA) was prescribed for 591 patients (59%), of whom 8.5% had no international normalized ratio follow-up tests for at least 3 months before our review. Among patients in the VKA treatment group the risk for thromboembolic events was considered to be high, moderate and low in 22% (n=131), 66% (n=391) and 12% (n=69), respectively. Patients with a low Congestive Hypertension Age Diabetes Stroke (CHADS2) score (odds ratio = 0.555, 95% confidence interval 0.357-0.862) and patients who did not receive VKA (OR = 0.601, 95% CI 0.459-0.787) received significantly less rate-control treatment. Of the patients with a low CHADS2 score (< 1) 52.7% received VKA treatment, and 39.4% with a high CHADS2 score (> or = 3) did not receive VKA. A positive correlation was found between anticoagulation and rate or rhythm control. The prevalence and age distribution of AF in southern Israel are similar to findings in the western world. Many of the patients did not receive appropriate antithrombotic prophylaxis.