Chest thump is a simple method of trrciimunt of some paroxysmal arrhythmias. Its therapeutic efficacy, electrophysiological bases and clinical utility have been studied in 17 patients during 45 episodes of ventricular tachycardia (VT). Thumping the precor-dium interrupted the VT in 22 episodes. Three types of interruption of VT huvr been observed: (1) In 15 episodes, single ventricular premature beats induced by the Mow, occurring randomly in the cycle, stopped the arrhylhmia; (2) In episodes, a run of premature beats, induced by a rapid succession of blows, interrupted the tachycardia; (3) In 2 episodes, chest thump caused a short period of asystole followed by sinus rhythm. Chest thump is an antiarrhythmic treatment of definite clinical utility. The complications are rare, although (here is a possibility of ventricular fibrillation. Therefore, it should be performed only under careful supervision.