The objective of the work was to describe in subjects with spontaneous ventricular fibrillation, after elimination of acute cardiac disease, the strategy of antiarrhythmic treatment and to evaluate, based on prospective follow-up, the effectiveness of this treatment. The authors included in the group 36 patients (30 men and 6 women) within the range from 34 to 78 years (mean age 58 +/- 11 years) with spontaneous ventricular fibrillation. They divided the group into a subgroup (15 subjects) without revascularization of the heart muscle, into a subgroup (17 subjects) with revascularization of the myocardium (coronary angioplasty and bypasses) and a subgroup (4 subjects) where ischaemic heart disease was ruled out (mostly cardiomyopathies). In all subgroups they used programmed ventricular stimulation (apparatuses of Quinton Co. USA, Biotronik Co. GFR), in the subgroup with revascularization within 3 months. During the diagnostic procedure of ventricular stimulation they tested antiarrhythmic drugs most frequently amiodarone per os (for 4 weeks). An implantable cardioverter--defibrillator was implanted in 17 patients (8 subjects without revascularization, 6 subjects with revascularization, 3 subjects without ischaemic heart disease). All patients were followed up till death, maximum 24 months. The authors evaluated the rate of cardiac deaths (death on cardiac grounds, incl. sudden arrhythmic death) and sudden arrhythmic deaths (within one hour after the onset of symptoms or the first malignant ventricular tachyarrhythmia recorded after implantation of the defibrillator). In the subgroup without revascularization with electric instability of the ventricles according to programmed stimulation 66.7% they described seven cardiac deaths (46.7%) and 6 sudden "arrhythmic" deaths (40%) incl. 5 subjects with ineffective testing of antiarrhythmic drugs. Conversely in the subgroup with revascularization and with diagnostic programmed stimulation in 47.1% they found 3 cardiac deaths (17.7%), one sudden "arrhythmic" death (5.9%)--a subject with ineffective testing. In the subgroup without ischaemic heart disease they recorded cardiac and sudden "arrhythmic" deaths in half the subjects, in all instances in subjects without inducible ventricular tachyarrhythmia. The authors found in the course of a two-year investigation a relapse of cardiac arrest in 25% of subjects after spontaneous ventricular fibrillation. A third of these subjects (all without a cardioverter-defibrillator) died. They confirm the benefit of implantation of a defibrillator for all subjects regardless of the basic diagnosis and revascularization of the heart muscle.