During prolonged global ischemia in isolated rabbit hearts, ventricular fibrillation showed a lower dominant frequency on the left ventricular epicardium (5.0 Hz) than the right (8.6 Hz, P<0.001).
During prolonged global ischemia in isolated rabbit hearts, ventricular fibrillation is driven by a single subepicardial source, and the dominant frequency in the left ventricle is not higher than in the right ventricle.
Absolute Event Rate: 5% vs 8.6%
p-value: p=< 0.001
INTRODUCTION: The dominant frequency (DF) during ventricular fibrillation (VF) in Langendorff-perfused guinea pig hearts is higher in left ventricle (LV) than in right ventricle (RV). However, the onset of VF invariably leads to global ischemia. Whether or not a high DF source exists in LV during global ischemia is unknown. METHODS AND RESULTS: By using a two-camera optical mapping system, epicardial activation patterns of VF were studied in 12 isolated rabbit hearts during baseline, no-flow global ischemia, and reperfusion. Simultaneous endocardial electrode recording was performed in 4 of the 12 hearts. Optical mapping showed type 1 VF at baseline, with multiple wandering and short-lived wavelets. After the onset of global ischemia, VF showed progressively increased spatiotemporal periodicity. The majority (65%) of VF recorded after 7 minutes of global ischemia showed type 2 VF, containing a single epicardial site with stable (> or = 3.85 seconds in duration) repetitive activities. Among the 33 sites with these activities, 24 were located near the interventricular septum, and 27 showed an epicardial breakthrough pattern with centrifugal propagation and wavebreaks distant from the focal site. After 10 minutes of global ischemia, the DF was lower on LV epicardium (5.0 +/- 1.4 Hz) than on RV epicardium (8.6 +/- 2.5 Hz, P < 0.001). However, there was no DF gradient between RV and LV endocardium (9.7 +/- 1.0 vs 9.6 +/- 0.9 Hz). CONCLUSIONS: VF during prolonged global ischemia is consistent with type 2 VF with a single subepicardial source of rapid activation, mostly near the interventricular septum. The DF in LV is not higher than in RV.
Wu et al. (Tue,) conducted a other in Ventricular fibrillation during global ischemia (n=12). No-flow global ischemia vs. Baseline was evaluated on Dominant frequency on LV vs RV epicardium after 10 minutes of global ischemia (p=< 0.001). During prolonged global ischemia in isolated rabbit hearts, ventricular fibrillation showed a lower dominant frequency on the left ventricular epicardium (5.0 Hz) than the right (8.6 Hz, P<0.001).