AIM: To investigate relations between heart rhythm variability (HRV), vegetative balance and electric myocardial activity in myocardial infarction (MI) survivors. MATERIAL AND METHODS: HRV was studied by short 5-min parts of ECG and data of ECG Holter monitoring were analysed for 98 patients who had macrofocal MI 1.5 months to 5 years before. RESULTS: Manifestations of electric heart instability were polymorphic. 69.4% examinees had hyperactivity of the parasympathetic nervous system (PSNS). The influence of the sympathetic nervous system (SNS) increased with growing severity of arrhythmia. Supraventricular arrhythmia occurred more frequently in high PSNS activity, while ventricular arrhythmia occurred more often in SNS prevalence combined with low HRV. CONCLUSION: HRV analysis for MI survivors, especially in combination with Holter ECG monitoring, gives an objective assessment of various manifestations of cardiac dysfunction and therefore enables timely adequate therapy.