To detect and analyse episodic ventricular tachycardia(EVT)in ambulatory patients, 24 h electrocardiographic recordings were performed in 57 consecutive patients with stable heart disease.Total number of EVT was 316.212 episodes( 68%)oc cured in day time when the patients were going about everyday activities.104 episodes(33%)occured during sleep.ST elevation or depression were noted in 154 episodes before on set of EVT,suggesting EVT might be related to myocardial ischemia.312 episodes(98.7%)had premature index(R-R'QT)≥1 indicating the majority of of EVT were not triggered by "Ron on T" phenomenon. Average vulnerability index(RR ×OT)/RR'was 0.54, index value greater than one was not observed,most EVT were not associated with high vulnerability index. None of the 316 episodes terminated in vertricular flutter or ventricular fibrillation.