Abstract 73: Changes in AMSA During Controlled Coronary Perfusion by Extracorporeal Circulation in a Swine Model of Ventricular Fibrillation

Background: Previous VF studies in rats showed that 6 min of CPR was needed before an electrical shock could be successful in reestablishing cardiac activity. During this interval the amplitude spectral area (AMSA) - a method of VF waveform analysis - progressively rose reaching a plateau within the same interval required for enabling successful defibrillation. No previous studies have examined AMSA continuously using a model of tightly controlled CPR. Methods: VF was induced and left untreated for 8 min in 16 swine after which extracorporeal circulation (ECC) was maintained for 10 min adjusting its flow to generate a coronary perfusion pressure of 10 mmHg. AMSA was calculated from the VF signal in the frequency domain within 2-48 Hz and analyzed continuously with a 2.1 s timeframe and a Tukey window that moved ahead every 0.5 s. Results: AMSA progressively declined during untreated VF. During ECC, AMSA rose from 6.8±1.9 to 12.4±4.1 mV*Hz (p<0.001). The increase occurred early during ECC and plateaued aft...