A new organization has been formed in which ambulance personnel have been trained to recognize ventricular tachycardia and ventricular fibrillation (VF) and to defibrillate. Cardiac arrest (CA) occurred in 307 patients and 140 were defibrillated. Twenty-eight patients were resuscitated and admitted for further hospital care. A previous history of ischaemic heart disease was found in 24 patients. Twenty-two of the patients admitted were found to have VF, two asystole and four other rhythms. All 11 survivors regained circulation at the site of the CA. At the time of admission all but one of the patients were unconscious and one long-time survivor remained unconscious until the 5th day following admission. Seventeen patients died while still in hospital. In 16 cases a diagnosis of acute myocardial infarction was established, a further six had VF without evidence of acute myocardial infarction and six had other diagnoses. Ten out of the 11 survivors were still alive six months after discharge. Only one case of recurrent VF was seen during a median follow-up period of 16 months. Prolonged coma, especially in combination with convulsions, was associated with a poor prognosis, while early return of circulation was significantly more common among survivors. Ongoing medication with beta-blockers, a high QRS rate on admission and VF without proof of any acute myocardial infarction were also found to be more common in survivors.