Recovery of ventricular pressure after long-duration fibrillation/asystole

When ventricular fibrillation occurs out-of-hospital, fewer than 3% of patients survive to hospital discharge. Following long fibrillation durations associated with out-of-hospital fibrillation, asystole or electromechanical dissociation (EMD) frequently follows the defibrillating shock. When this happens, recovery of spontaneous circulation rarely occurs. Therefore, this study tested the hypothesis that ventricular recovery from asystole or EMD is possible if the heart is subsequently perfused at normal pressures with O₂ saturated solution. Isolated rabbit hearts (n=5) were subjected to 9 minutes ischemic fibrillation followed by a defibrillating shock. All hearts converted to asystole or EMD. At 23 seconds following the shock, the hearts were reperfused with oxygenated solution. Ventricular pressure recovered 57.2±11.9% of control at 36.0±1.9 seconds and 76.2±11.8% at 5 minutes. These results suggest that rapid pressure recovery is possible after 9 minutes of ischemic fibrillation where the defibrillating shock leads to asystole or EMD, and that recovery can occur in the absence of epinephrine or CPR prior to the shock