Direct endocardial mapping during ventricular fibrillation in isolated canine hearts identified 1018 activation wave fronts, including 142 propagating from Purkinje fibers to working myocardium.
Purkinje fibers are highly active during the first 10 minutes of ventricular fibrillation, showing both antegrade and retrograde propagation, suggesting their importance in VF maintenance.
BACKGROUND: The roles of Purkinje fibers (PFs) and focal wave fronts, if any, in the maintenance of ventricular fibrillation (VF) are unknown. If PFs are involved in VF maintenance, it should be possible to map wave fronts propagating from PFs into the working ventricular myocardium during VF. If wave fronts ever arise focally during VF, it should be possible to map them appearing de novo. METHODS AND RESULTS: Six canine hearts were isolated, and the left main coronary artery was cannulated and perfused. The left ventricular cavity was exposed, which allowed direct endocardial mapping of the anterior papillary muscle insertion. Nonperfused VF was induced, and 6 segments of data, each 5 seconds long, were analyzed during 10 minutes of VF. During 36 segments of data that were analyzed, 1018 PF or focal wave fronts of activation were identified. In 534 wave fronts, activation was mapped propagating from working ventricular myocardium to PF. In 142 wave fronts, activation was mapped propagating from PF to working ventricular myocardium. In 342 wave fronts, activation was mapped arising focally. More than 1 of these 3 patterns could occur in the same wave front. CONCLUSIONS: PFs are highly active throughout the first 10 minutes of VF. In addition to retrograde propagation from the working ventricular myocardium to PFs, antegrade propagation occurs from PFs to working ventricular myocardium, which suggests PFs are important in VF maintenance. Prior plunge needle recordings in dogs indicate activation propagates from the endocardium toward the epicardium after 1 minute of VF, which suggests that focal sites on the endocardium may represent foci and not breakthrough. If so, in addition to reentry, abnormal automaticity or triggered activity may also occur during VF.
Tabereaux et al. (Tue,) conducted a other in Ventricular fibrillation (n=6). Direct endocardial mapping during nonperfused ventricular fibrillation was evaluated on Purkinje fiber or focal wave fronts of activation. Direct endocardial mapping during ventricular fibrillation in isolated canine hearts identified 1018 activation wave fronts, including 142 propagating from Purkinje fibers to working myocardium.