Comparison of biphasic and monophasic defibrillation waveforms in an isolated rabbit heart preparation

Study objective — The aims were to develop a Langendorff rabbit heart model and to compare monophasic and biphasic defibrillation pulses. Design — Hearts were perfused with a Krebs-Henseleit solution and two 1.4 cm2 Pt-Ir mesh patch electrodes were sutured onto the ventricles. A 5 ms monophasic or 10 ms biphasic pulse, with randomly selected voltages of 30, 50, 70,90,110, or 130 V, defibrillated the heart after 10 s of fibrillation. Subjects — 11 adult male New Zealand white rabbits weighing 2.8(0.27) kg, were used for the studies. Measurements and main results — A total of 72 fibrillation and defibrillation sequences were conducted in each preparation. The results were fitted to a sigmoidal dose-response curve by logistic regression analysis. Voltage and energy values from the fitted data at 50% and 80% success (V50, V80, E50, E80) indicated a significantly lower (p