The Belfast experience with resuscitation ambulances.
The majority of sudden deaths are due to ventricular fibrillation. In the initiation of ventricular fibrillation, an R on T extrasystole was the most important factor. A late cycle ectopic, ventricular tachycardia and idioventricular rhythm initiated ventricular fibrillation less frequently. An increase or marked slowing of the heart rate were predisposing factors in the initiation of ventricular fibrillation. The first successful correction of ventricular fibrillation outside the hospital was achieved by the Belfast Mobile Coronary Care Unit in 1966. A single shock of 100 or 200 watt seconds (stored) was highly successful in the correction of ventricular fibrillation. The most likely factor in unsuccessful defibrillation is incorrect paddle application. For the correction of ventricular fibrillation during the first hour of the onset of symptoms, less than or equal to 2DC shocks were required in 41% of patients. Only 8% of patients required more than ten shocks. Smaller portable defibrillators are now available for use by family practitioners. Lidocaine 100 mg intravenously and 300 mg intramuscularly failed to prevent the development of ventricular tachycardia and ventricular fibrillation during the first hour of the drug's administration. Patients who survived ventricular fibrillation that occurred within four hours of the onset of symptoms of myocardial infarction were younger, tended to have had a mild coronary attack, and had the most favorable long-term prognosis. The early control of chest pain, autonomic disturbances, arrhythmias, and hemodynamic disturbance leads to a reduced incidence of cardiogenic shock and hospital mortality.
D000552:Ambulances; D004554:Electric Countershock; D004630:Emergencies; D004632:Emergency Medical Services; D006323:Heart Arrest / Q000628:therapy*; D006801:Humans; D009660:Northern Ireland; D012151:Resuscitation; D014693:Ventricular Fibrillation / Q000628:therapy*