[Comparison of clinical characteristics between elderly and young patients with bradycardia less than 80,000 beats per 24 hours].

Few researchers have conducted 24-hour total heart beat (THB) studies in patients with bradycardia, and its prevalence and significance in the elderly remain controversial. The aim of this study was to compare of distribution of THB, underlying diseases and effects of medication on THB in inpatients with bradycardia less than 80,000 beats/24 hrs between elderly and young patients. There were 303 Holter monitorings of bradycardia out of 7,687 consecutive monitorings, with only the earliest monitoring registered when duplicating. The age distribution of these 303 patients with bradycardia showed a two-peak pattern: a large peak at age 65-70 and a small peak at age 15-20. Thus we divided them into a young group aged under 65 (194 patients: mean 49.1) and an elderly group aged 65 or more (109 patients: mean 71.0). There was no difference in mean THB or distribution of THB between the two age groups, irrespective of medication which had a side effect of bradycardia. Underlying diseases included three bradyarrhythmias; such as sinus bradycardia, sick sinus syndrome and II or III degree AV block, long QT syndrome, ischemic heart disease, cardiomyopathy, valvular disease and others. There was no difference in mean THB or distribution of THB between the two age groups in each disease group. Moreover, with respect to bradyarrhythmias, there was a small distribution of THB between 75,000 and 70,000 beats/24 hrs in patients without medication while there was a sparse distribution of THB in patients with medication.