[Incidence of weak sinus syndrome in patients with sinus bradycardia and prognosis].

A total of 270 patients with sinus bradycardia were studied to detect the sick sinus syndrome (SSS) in them and to determine the impact of sex, age, heart rate and atropine test on sinus function recovery time (SFRT) and corrected sinus function recovery time (CSFRT). The study indicated that CSFRT which is pathological at a duration of 525 msec or more was most valuable in the diagnosis of the sick sinus syndrome. Responses to atropine tests were significantly different in healthy persons and in patients with lower automatic sinus function. Increases in heart rate during the atropine test by less than 70% of the baseline suggests an organically decreased automatic function. In patients with sinus bradycardia, the age was related to SFRT to a lesser extent, when the baseline heart rate only in males affected SFRT rather than CSFRT. After atropine administration and its percentage increase, heart rate was found to be closely related to SFRT and CSFRT.