Frequency of cardiac arrhythmias in older adults: Findings from the Subclinical Atrial Fibrillation and Risk of Ischemic Stroke (SAFARIS) study

Background: Prolonged monitoring of cardiac rhythm has been used to screen for subclinical atrial fibrillation (AF); little is known about other arrhythmias in the general population, especially in the elderly, who are at higher risk of arrhythmias. Methods: We evaluated the frequency of arrhythmias in the tri-ethnic (white, Black, Hispanic), community-based Subclinical Atrial Fibrillation and Risk of Ischemic Stroke (SAFARIS) study using a patch-based recorder for up to 14 days in 527 participants free of AF, congestive heart failure (CHF) or history of stroke. Differences according to gender, age, ethnicity and presence of hypertension, diabetes and pertinent ECG and echocardiographic variables were examined. Results: Mean age was 77.2 ± 6.8 years (37.2% men, 62.8% women). AF was present in 10 participants (1.9%), only 2 of them symptomatic. Supraventricular tachycardia (SVT) and ventricular tachycardia (VT) episodes were observed in 84.4% and 25.0% but only 13.5% and 10.6% of participants reported symptoms, respectively. Severe bradycardia (<40 bpm) was present in 12.5%. Sinus pauses and high-degree atrioventricular blocks were infrequent (2.1% and 1.5%, respectively). Most arrhythmias were more frequent in participants > 75 years; ventricular arrhythmias and severe bradycardia were more common in men. Whites had significantly more episodes of AF than Hispanics, SVT than Blacks and VT ≥ 10 beats than Hispanics and Blacks. Hypertensives had more episodes of severe bradycardia. LV hypertrophy or LVEF <55% were associated with more frequent ventricular and supraventricular arrhythmias. Conclusions: Prolonged cardiac rhythm monitoring revealed moderate frequency of AF, but higher than expected frequencies of AF-predisposing arrhythmias. Ventricular arrhythmias were relatively frequent, whereas severe bradyarrhythmias were infrequent.