History of the ICD

TOWARDS the latter part of the 1960s, cardiac defibrillation, by external means, was considered an effective treatment for terminating ventricular fibrillation. Elective cardioversion, using the same external defibrillating devices, was also a commonly used therapy for the conversion of ventricular tachycardia, atrial fibrillation, and atrial flutter to more normal rhythms. These cardioversion devices utilized a synchronization of the defibrillator discharge with the patient’s own R-wave so as to prevent induction of ventricular fibrillation from cardioversion shocks that otherwise may have been delivered during the vulnerable portion of the cardiac cycle (the early portion of the T-wave). The history of the ICD also began during this period, at the time when the idea was first conceptualized by Michel Mirowski.