Abstract 1356: Is Human Ventricular Fibrillation Different From Experimental Models?
Introduction: There is a paucity of data on wavefront dynamics during human VF. Some experimental models show multiple small wavelets, whilst others implicate a single stationary rotor. We have studied human VF using phase and wavefront analysis based on global epicardial mapping.
Methods: VF was induced by burst pacing in 10 patients undergoing routine cardiac surgery. For each subject, a 20 – 40 s episode of VF activity was sampled at 1 kHz using an epicardial sock containing 256 unipolar contact electrodes connected to a UnEmap system. Wavefronts were determined from the phase plane (based on de-trended voltage versus its Hilbert transform) using an active-edge algorithm to track the isolines of zero phase. Wavefront sizes and rotor statistics were tallied across all patients.
Results: As illustrated, one or more wavefronts of at least 10 cm in size were present for 90% of the VF duration. Insert shows a polar projection of wavefronts between pairs of phase singularities. Large convoluted wavefronts were predominant with at least one wavefront of size > 20 cm present for over half of the VF duration. Persistent epicardial rotors (defined as those with lifetimes greater than 1000 ms, or approximately 5 rotations) were present for more than 78% of the total VF duration, whilst two or more persistent rotors were present more than half of the time.
Conclusion: Epicardial mapping in humans suggests that neither multiple wavelets nor a single persistent stationary rotor, as seen in experimental models, drive VF. Instead, in all subjects the predominant characteristic was multiple mobile rotors of moderate duration (1000 –7000 ms), which generated large make and break wavefronts.