[Effect of aprindine in patients with normal and pre-damaged impulse forming and excitation conducting system/First communication; Sinus node function (author's transl)].

In 18 patients the influence of aprindine on sinus node function has been evaluated. The criteria were heart rate in spontaneous rhythm, sinus node recovery time (SRT), and the warm-up period after atrial stimulation with frequencies between 90 and 140/min. After aprindine the spontaneous rate increased significantly, whereas SRT and the warm-up period were not affected significantly. The patients with sinu-atrial disease showed a shortening of the spontaneous cycle-length and a decrease in SRT after aprindine. The results are discussed regarding the electrophysiological characteristics of the sinus node (slow current, automaticity) and their changes produced by stimulation and aprindine.