title: Sinoatrial function in old age.
abstract: The purpose of our study was to investigate the effects of old age on sinoatrial function. We analyzed data obtained from 35 normal adults who were divided into 3 Groups: A (20-40 years, n=11), B (41-61 yrs, n=12). We evaluated: mean sinus node cycle length, sinus node recovery time, corrected sinus node recovery time, effective and functional refractory periods (EARP and FARP) and sinoatrial conduction time. EARP and FARP in Group C were significantly longer than in Group A (P less than 0.0025 and P less than 0.0005, respectively) and in Group B (P less than 0.005 and P less than 0.025, respectively). The differences were significant also when the values were expressed in percent of SCL (Group A vs Group C: P less than 0.005 for EARP, and P less than 0.005 for FARP; Group B vs Group C: P less than 0.025 for EARP and P less than 0.025 for FARP). These were the only significant differences observed between the three groups. Our data indicate that in normal adults the aging process does not affect sinus node automatism and impulse spread to the atrium, while atrial refractoriness is lengthened significantly.
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging; D002304:Cardiac Pacing, Artificial; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012849:Sinoatrial Node / Q000502:physiology*