Echocardiographic and clinical risk factors for atrial fibrillation in hypertensive patients with ischemic stroke.

Atrial fibrillation (AF) is a common cause of ischemic stroke. Because anticoagulation can prevent many of these strokes, identifying patients with occult intermittent AF is important. Hypertension is a common precursor of stroke and AF. Prolonged nonselective electrocardiographic monitoring of patients after ischemic stroke has yielded only a small number of patients with occult intermittent AF. To determine the importance of AF in nonhemorrhagic stroke, we retrospectively studied 799 patients admitted with ischemic stroke over 31 months. AF was present on the admitting electrocardiogram in 154 patients (19.3%), diagnosed later during the stroke admission in 58 (7.3%), and found only during another admission before/after the stroke admission in 46 (5.8%). AF was intermittent in 123 patients, 47.7% (95% CI 41.6 to 53.8) of patients with AF, and not present on initial electrocardiogram in 40.3% of patients with AF. In 633 patients with hypertension, AF occurred in 34.9% versus 22.2% without hypertension (p <0.01). Echocardiogram revealed a left atrium > or =4.0 cm in 81.3% of patients with AF versus 42.4% of those without AF (odds ratio [OR] 5.85, 95% confidence interval [CI] 3.87 to 8.96, p <0.001); ejection fraction was <50% in 27.7% of patients with AF versus 12.6% of those without AF (OR 2.63, 95% CI 1.65 to 4.22, p <0.001); and the left ventricle was > or =5.6 cm in 13.8% in patients with AF versus 6.7% in those without AF (OR 2.21, 95% CI 1.61 to 3.04, p <0.01). Clinically, congestive heart failure (31% vs 10.4%, OR 3.89, 95% CI 2.76 to 5.73) and coronary disease (31% vs 21.4%, OR 1.65, 95% CI 1.15 to 2.37) were present more often in patients with AF (p <0.001). Left ventricular hypertrophy, diastolic dysfunction, and diabetes were common in all hypertensive patients with stroke. In conclusion, hypertensive patients with these risk factors should undergo prolonged electrocardiographic event monitoring to identify occult intermittent AF so measures can be taken to prevent a second stroke and possibly a first stroke.