Atrial electrophysiological characteristics of aging.

INTRODUCTION Advancing age is a known risk factor for developing atrial fibrillation (AF), yet it is unknown which electrophysiological changes contribute to this increased susceptibility. The goal of this study is to investigate conduction disturbances and unipolar voltages (UV) related to aging. METHODS We included 216 patients (182 male, age: 36-83 years) without a history of AF undergoing elective coronary artery bypass surgery. Five seconds of sinus rhythm were recorded intraoperatively at the right atrium (RA), Bachmann's bundle (BB), the left atrium and the pulmonary vein area (PVA). Conduction delay (CD), -block (CB), -velocity (CV), length of longest CB lines and UV were assessed in all regions. RESULTS With aging, increasing conduction disturbances were found, particularly at RA and BB (RA: longest CB line rs  = .158, p = .021; BB: CB prevalence rs  = .206, p = .003; CV rs  = -.239, p < .0005). Prevalence of low UV areas (UV <5th percentile) increased with aging at the BB and PVA (BB: rs  = .237, p < .0005 and PVA: rs  = .228, p = .001). CONCLUSIONS Aging is accompanied by an increase in conduction disturbances during sinus rhythm and a higher prevalence of low UV areas, particularly at BB and in the RA. These electrophysiological alterations could in part explain the increasing susceptibility to AF development associated with aging.