Abstract 168: Effect of Cardiopulmonary Resuscitation on Restoration of Myocardial ATP in Prolonged Ventricular Fibrillation
Background: It is known that a short period of cardiopulmonary resuscitation (CPR) prior to defibrillation improves survival in patients with unwitnessed sudden collapse. However, there has been no report about whether CPR restores myocardial ATP during prolonged ventricular fibrillation (VF). The aim of this study is to investigate the effect of CPR on restoration of myocardial high energy phosphate in prolonged VF.
Methods and Results: Seventy two adult male Sprague-Dawley rats (330–400 g) were enrolled in the study. Baseline ATP and ADP prior to induction of VF were measured from 9 animals. Sixty three animals were subjected to 4 minutes of untreated VF. Then, animals were randomized into no-CPR group (n=37) and CPR group (n=26). In no-CPR group, ATPs and ADPs were measured 4 (n=9), 6 (n=10), 8 (n=8), and 10 (n=10) minutes after induction of VF, respectively. CPR group received 2 (n=10), 4 (n=8), and 6 (n=8) minutes of mechanical chest compressions, respectively. Baseline myocardial ATP (nmol/mg<zmd>protein) and ATP/ADP ratio was 5.49±1.71 and 0.23±0.12. Myocardial ATP in no-CPR group decreased as duration of VF was prolonged (4.27±1.58 at 4 min, 4.13±1.31 at 6 min, 3.77±1.42 at 8 min, and 3.52±0.90 at 10 min, respectively; p<0.05 at 8 min and 10 min vs. baseline). Myocardial ATP after 2 min of CPR was restored to baseline level and decreased as CPR time was prolonged (5.27±1.67 after CPR for 2 min, 3.77±1.05 after CPR for 4 min, and 3.49±1.08 after CPR for 6 min, respectively; p<0.05 after CPR for 4 min and 6 min vs. baseline). Myocardial ATP/ADP ratio in no-CPR group tended to be lower (0.13±0.05 at 4 min, 0.15±0.04 at 6min, 0.17±0.06 at 8 min, and 0.17±0.05 at 10 min, respectively) than baseline level. Myocardial ATP/ADP ratio after 2 min of CPR increased to baseline level and tended to decrease as CPR time was prolonged (0.26±0.15 after CPR for 2 min, 0.20±0.09 after CPR for 4 min, and 0.19±0.03 after CPR for 6 min, respectively).
Conclusions: Myocardial ATP decreases as duration of ventricular fibrillation is prolonged. CPR for 2 minutes after prolonged ventricular fibrillation restores myocardial ATP.
- © 2010 by American Heart Association, Inc.