Studies of ambulance patients with ischemic heart disease. 1. The outcome of pre-hospital life-threatening arrhythmias in patients receiving electrocardiographic telemetry and therapeutic interventions.

Patient delay in seeking medical assistance for acute ischemic heart disease and the incidence of potentially life-threatening arrhythmias en route to the hospital were examined in a 22-month community trial of ambulance telemetry. Of 7,654 patients transported, 179 who had electrocardiograms (ECGS) transmitted were found to have had acute MIs or acute myocardial ischemic events. Fifty per cent of these patients summoned an ambulance within 30 minutes and 72 per cent within two hours after the onset of acute symptoms. Fifty-eight patients had potentially life-threatening arrhythmias. Interventions with drugs and/or defibrillation was required in 22 patients with or without cardiopulmonary resuscitation (CPR); intervention with CPR alone was required in six patients. Twelve of these 28 patients survived through hospital admission and six were alive at three months. The relatively low outcome/input ratio of this experience necessitates re-evaluation of the epidemiological characteristics and patient selection criteria in populations considered for telemetry.