Abstract P72: Human Model for the Study of Cardio Pulmonary Resuscitation Using Wavelets
Background: It is practically not feasible to test the effects of global ischemia, varying blood flow, and adequacy of CPR on live humans during VF.
Objective: We tested the hypothesis that the parameters affecting the success of defibrillation can be studied using a human Langendorff setup and wavelet analysis of the VF episodes.
Methods: We analyzed VF in isolated human hearts using a Langendorff setup using an ischemia-reperfusion protocol. As soon as VF was induced, perfusion was turned off for 200s mimicking global ischemia during which three 20s electrograms were recorded using 112 electrodes on the epi and endocardium. At the end of the period of ischemia, the perfusion system was turned back to baseline for 140s and two 20s electrograms were recorded. The hearts were then defibrillated and this protocol was repeated twice after 5 min of rest. The electrograms during ischemia and reperfusion were analyzed using continuous wavelet transform (CWT).
Results: In the Figure⇓, the top panel shows a sample electrogram recorded during the last 20s of ischemia and reperfusion. The bottom 4 panels show the average normalized contribution of wavelet scales in representing the electrograms recorded during last 20s of ischemia and reperfusion stages in the LV and RV epicardium. Analyzing the panels it is evident that more scales contribute during ischemic stage than the reperfusion stage indicating a shift in waveform complexity.
Conclusion: Human Langendorff setup is ideal for studying the ischemia-reperfusion protocols using controlled flow rates. Wavelet analysis of the VF episodes holds the potential use in differentiating perfusion states and thus the efficacy of chest compressions.