The objective of the work was the long-term perspective follow-up of subjects with a normal and pathologically delayed intra-, infra-His conduction in the heart based on the electrogram of the bundle of His and subjects with a normal or pathological finding during programmed stimulation of the ventricles, to assess the impact of these findings for the patients' prognosis. The authors included in the group, after elimination of subjects with the syndrome of ventricular preexcitation, 340 patients (243 men, 97 women, 16-81 years, mean age 49 +/- 16) where they made an invasive electrophysiological examination of the heart (electrogram of the bundle of His without cardiac stimulation, during graded and programmed stimulation of the atria, in 206 subjects also programmed stimulation of the ventricles) not before three months after acute cardiac disease. The authors found normal HV intervals or a normal length of H waves in 286 patients and delayed values in 54 patients. They revealed a diagnostic conclusion of programmed ventricular stimulation in 71 subjects and a non-diagnostic conclusion in 135 subjects. All patients were followed up irrespective of implantation of a pacemaker and antiarrhythmic treatment for 6 to 144 months (mean follow-up period 56.1 months). During the mentioned period they described the occurrence of cardiac deaths (deaths from cardiac causes) in 29 subjects with a normal intra-, infra-His conduction (10.1%), in 12 subjects with delayed intra-, infra-His conduction (22.2%), in 7 subjects with undiagnosed programmed ventricular stimulation (5.2%) and in 13 subjects with diagnosed programmed ventricular stimulation (18.3%).(ABSTRACT TRUNCATED AT 250 WORDS)