Abstract 13871: Dominant Frequency Gradient Across Left Ventricular Wall During Ventricular Fibrillation in Ischemic vs. Dilated Cardiomyopathic Human Hearts
Background: Transmural dominant frequency gradient during ischemic ventricular fibrillation (VF) has been reported in several animal and human models. In this study we compared transmural dominant frequency gradient, during VF, in ischemic and dilated cardiomyopathic human hearts.
Methods and Results: The study was conducted in human langendorff model. These were ischemic (ICM, n=5) and dilated (DCM, n=5) cardiomyopathic human hearts explanted from patients undergoing cardiac transplant. Data was collected using an epicardial sock and an endocardial balloon each having 112 unipolar electrodes, arranged in 14 columns and 8 rows. Ischemia was induced by halting the perfusion to the heart and VF was initiated by brief application of 9V batter to epicardium. VF was recorded at onset, 90 seconds and 180 seconds for 20 seconds each. Heart was perfused and additional VF episodes were recorded. Dominant frequency (DF) was computed using Welch periodogram method as described in our previous studies. Repeated measure ANOVA was employed using mixed model in SAS.
Results: The mean DF in LV-endocardium and LV-epicardium is reported in table 1. At the onset of VF, no statistically significant difference was observed between LV epicardium and endocardium in dilated cardiomyopathic hearts (p=0.6) while the difference was statistically significant in ischemic cardiomyopathic hearts (p<0.05). After 180 seconds of VF, there was significant transmural DF gradients in both ischemic and dilated cardiomyopathic hearts that was attenuated by 2 minutes of reperfusion in DCM hearts (p=0.9) but was not attenuated in ischemic cardiomyopathic hearts (p<0.05).
Conclusion: There is a LV transmural DF gradient during VF in both DCM and ICM after 3 minutes of ischemia. This gradient is established early in ischemia in ICM but not in DCM. This transmural DF gradient is attenuated by reperfusion in DCM hearts but not in ICM hearts. This might relate to differential expression of KATP channels.
- © 2011 by American Heart Association, Inc.