Twenty-four—hour ambulatory electrocardiography in elderly subjects: Prevalence of various arrhythmias and prognostic implications (report from the Bronx Longitudinal Aging Study)

Abstract

Functional, ambulatory, community-dwelling subjects ( n = 423, aged 75 to 85 years) underwent baseline 24-hour ambulatory electrocardiography (ECG) examinations as part of the Bronx Aging Study, a 10-year prospective cohort study designed to identify risk factors and disease markers for cardiovascular, cerebrovascular, and dementia illnesses in old people. Premature ventricular contractions were the most commonly observed arrhythmia noted (93% of subjects), with a low prevalence of nonsustained ventricular tachycardia (5%), paroxysmal atrial tachycardia (13%), atrial fibrillation (4%), and atrioventricular blocks (4%). A 24-hour sinus rate of <60 beats/min was noted in 13% of subjects, and 11% of subjects were noted to have transient episodes of severe bradycardia (<40 beats/min). In a multivariate analysis, nonsustained ventricular tachycardia was an independent predictor of death ( p = 0.015; relative risk [RR] 2.8; 95% confidence interval [CI] 1.4 to 5.8) and myocardial infarction ( p = 0.031; RR 3.2; CI 1.2 to 9.4). Transient atrioventricular block was an independent predictor of stroke ( p = 0.0006; RR 9.7; CI 3.3 to 28.9), as was sinus bradycardia over a 24-hour period ( p = 0.033; RR 2.7; CI 1.2 to 6.4). Ventricular tachycardia approached significance as an independent predictor of multiinfarct dementia ( p = 0.052; RR 6.3; CI 1.4 to 28.7). Episodes of paroxysmal atrial fibrillation, atrial tachycardia, and severe bradycardia were not associated with adverse outcomes. Some arrhythmias found on the ambulatory ECG in very old subjects can predict an increased risk for subsequent death, myocardial infarction, stroke, and multiinfarct dementia.