[Features of the atropine test in persons of different ages]

The diagnostic value of the atropine test was investigated in 47 essentially healthy men of different age groups (25-39, 40-49 and 50-59 years). The cardiovascular responses were evaluated from ECG recorded continuously for an hour after subcutaneous injection of 1.0-0.1% atropine sulphate. Atropine caused a two-stage effect of the cardiac chronotropic function. The first, bradycarditic, stage was induced by vagal stimulation while the second, tachycarditic, stage was, by contrast, produced by atropine blockade of the acetylcholine effect on M-cholinoreceptors of myocardial cells. The atropine effect was identical in sign in all age groups. However, in the young age group the bradycarditic effect was more distinct and atropine-induced arrhythmias were more frequent. In the 50-59 years subjects the tachycarditic effect grew at a slower rate and the electric systole response to a higher heart rate was less pronounced.