Incidence of circulatory arrest in patients with acute myocardial infarction in coronary unit. Mechanism of their genesis and factors conditioning successful resuscitation.

The incidence, circumstances, and mechanism of development of cardiac arrest in 786 patients with myocardial infarction treated at a coronary care unit within a five-year period were studied and clinical factors are analysed with respect to success of resuscitation. One or more episodes of cardiac arrest occurred in a total of 156 patients (19.8%). Of these, 25 (16.0%) were successfully resuscitated and 131 (84.0%) died. At the clinical ward where the patients had been transferred after the acute stage, cardiac arrest occurred in additional 22 patients, of whom two were successfully resuscitated. Thus, the total number of successfully resuscitated patients throughout the five-year period was twenty-seven. The results of resuscitation were poorer in elderly patients, in those with anterior infarction, and above all in patients with severe symptoms of mechanical heart failure. Anamnestic factors (chronic angina pectoris, previous myocardial infarction, hypertension, diabetes mellitus, ischaemic disease of the lower limbs) were not significantly associated with the results of resuscitation. Primary ventricular fibrillation was the principal mechanism of cardiac arrest in 24 of the 27 patients successfully resuscitated, and its total incidence in the investigated group was 3%. The prognosis of resuscitation in patients with primary ventricular fibrillation was very good, and in all of them the resuscitation was successful and permanent.