Cardiac pacing in retrospect.

As precursors of permanent pacemakers, Lidwill (1929) and Hyman (1932) introduced temporary pacemakers for resuscitation. Callaghan (1950) intravenously paced the sinus nodal region for bradycardia in hypothermic dogs. Zoll (1952) used external electrodes to treat Adams-Stokes attacks, and Lillehei (1957) fixed stainless steel electrodes to the myocardium, successfully treating iatrogenic total atrioventricular block with a percutaneous pacemaker. Since 1951, by experimental and clinical use of ventricular fibrillation to obtain a functional cardiac standstill during open heart surgery, we used all known methods of stimulation to treat asystole or bradycardia after defibrillation. Since 1957, percutaneous stimulation by Adam-Stokes attacks has been performed. The most serious complication is infections along the electrodes causing death from sepsis. The solution of the problem was the implantation of the pacemaker and its energy supply. Percutaneous leads were used to study the different parameters for electric stimulation and to find the lowest frequency (to spare energy) with the best variation of cardiac output. In October 1958 in Stockholm a fixed rate pacemaker was implanted by thoracotomy. At present, the patient is living with his 23rd pacemaker. Four additional patients had pacemaker implantations until 1960. In 1961, Chardack and Greatbach successfully implanted pacemakers with mercury batteries. Johanson and Lagergren connected the pacemaker to an intravenous electrode to avoid thoracotomy. The enormous development in the electronic field made more elaborate pacemakers possible, and eliminated the risk of the fixed rate (interference, repetitive firing, and ventricular fibrillation).