Cardiac Arrhythmias and Stroke

Abstract

Background and Purpose —With the exception of atrial fibrillation (AF), little scientific attention has been given the associations between cardiac arrhythmias and incidence of stroke. We sought to study whether atrial and ventricular arrhythmias assessed during a 24-hour ambulatory ECG registration are associated with incidence of stroke. Methods —The population-based cohort “Men Born in 1914” was examined with 24-hour ambulatory ECG registrations at 68 years of age. Four hundred two men without previous myocardial infarction or stroke were included, and 236 of them had hypertension (≥160/95 mm Hg or treatment). Fourteen-year rates of stroke (fatal and nonfatal) and all-cause mortality were updated from national and regional registers. Frequent or complex ventricular arrhythmias was defined as Lown class 2 to 5. A high frequency of atrial ectopic beats (AEB) was defined as the fifth quintile (ie, ≥218 AEB per 24 hours). Results —Fifty-eight men suffered a first stroke during the follow-up. Stroke rates (per 1000 person-years) among men with AF (n=14), with frequent AEB (n=77), and without AF or frequent AEB (n=311) were 34.5, 19.5, and 11.6, respectively. The corresponding values among men with hypertension were 40.7, 32.3, and 14.7, respectively. Frequent AEB (compared with absence of AF and frequent AEB) was significantly associated with stroke among all men (relative risk=1.9; 95% CI, 1.02 to 3.4; P =0.04) and among hypertensive men (relative risk=2.5; 95% CI, 1.3 to 4.8; P =0.009) after adjustments for potential confounders. The increased stroke rates among men with Lown class 2 to 5 did not reach statistical significance. Conclusions —A high frequency of AEB is associated with an increased incidence of stroke.