Abstract: An automatic implantable defibrillator/cardioverter having a non-committed defibrillation/cardioversion algorithm. The defibrillator/cardioverter includes an ECG amplifier with automatic gain control (AGC) which detects the electrical activity of the heart for analysis by a cardiac condition detector. Logic is provided which receives input from the ECG amplifier and the cardiac condition detector for analyzing the heart activity. The non-committed defibrillation algorithm sensing begins upon the determination of an arrhythmia. The capacitor is charged while the heart activity is simultaneously monitored. After the capacitor is charged, a check is made on the duration of the last detected R-R interval while so charging the capacitor, and a comparison is made between this R-R interval and a preset value. If the last R-R interval is greater than the preset value, a non-committing period is entered which lasts approximately 2 seconds.