OBJECTIVE To find out whether is there a relation between electrophysiology laboratory ventricular arrhythmias through programmed ventricular stimulation, and the occurrence of relevant clinical events, particularly, sudden death, in patients victims of first episode of myocardial infarction. METHODS Twenty-seven patients (all males) who suffered non-complicated first myocardial infarction, with age varying from 47 to 70 (mean 54 +/- 6) years were prospectively and consecutively studied. Upon consent, patients were at first submitted to conventional cinecoronaryography and to programmed ventricular stimulation utilizing the S2, S3, S4 protocol, 30 days after infarction. Moreover, patients were submitted to continuous electrocardiographic (Holter system), exercise test, and radioisotopic studies for left ventricle ejection fraction (phase I). The last three studies were subsequently repeated at 6 and 12 months (phases II and III), respectively. RESULTS All patients had ventricular arrhythmia induced, and according to the kind of response, patients were grouped into: group I--repetitive ventricular response, RVR, nine (33.5%) patients; group II--non sustained ventricular tachycardia. NSVT, eight (29.5%) patients; group III--sustained ventricular tachycardia SVT, ten (37%) patients. The patients of three groups, when submitted to electrocardiographic exercise test and Holter system studies, revealed complex arrhythmias in all phases. One patient of group II suddenly died at home, and another was injured with syncope, whereas in group III, two suddenly died, one at home and the other at the admission to the hospital, after an acute myocardial infarction. All patients but one of group I, who had a non-fatal reinfarction, showed preserved ventricular function. CONCLUSIONS Holter system and electrocardiographic exercises test revealed complex dysrhythmia in the tree phases of the study, independently of the induced response; C--Holter system and electrocardiographic exercise test studies revealed no relation. between sudden death and the kind of ventricular induced response or complex arrhythmia. Ventricular arrhythmia induced with S2, S3 and S4 protocol in patients with preserved ventricular function seems to indicate results without predictive value for cardiac sudden death.