Abstract P47: The Differences Of Amplitude Spectrum Area During Cardiac Arrest And CPR In Rats With And Without Chronic Myocardial Ischemia
We have previously demonstrated that the Amplitude Spectrum Area (AMSA) of ventricular fibrillation (VF) waveforms serves as a sensitive predictor of successful resuscitation during cardiopulmonary resuscitation (CPR) in animals with normal coronary arteries. However, the AMSA values during VF in animals with abnormal coronary arteries remains unclear. In the present study, we investigate the changes of AMSA during VF and CPR in a rat model of chronic ischemia. Our hypothesis was that AMSA is decreased during cardiac arrest and CPR in rats with chronic myocardial ischemia in comparison to those with normal coronary arteries. Ten Sprague-Dawley rats weighing 450 –550g were anesthetized. A thoracotomy was performed and the left anterior descending coronary artery was ligated such as to produce chronic myocardial ischemia in 5 rats. The other 5 rats served as sham control. Four weeks later, cardiac arrest was induced and maintained for 6 minutes. CPR, including chest compressions and mechanical ventilation, was then performed for a 6 minute interval prior to attempted defibrillation. AMSA was continuously calculated by fast Fourier transform during VF and CPR. AMSA decreased during VF and it continuously increased during CPR prior to defibrillation in all the animals. AMSA values, however, were significantly lower during VF and CPR in rats with chronic myocardial ischemia in comparison to sham control rats (p<0.01 Figure⇓). No difference in return of spontaneous circulation was observed. The predictive AMSA values for successful resuscitation were significantly lower in rats with chronic ischemic heart disease in comparison with rats with normal coronary arteries.