Abstract 1784: Role of Purkinje Fibers in Post-Infarction Ventricular Tachycardia
Background: Ventricular fibrillation and polymorphic ventricular tachycardia (VT) in the setting of acute myocardial infarction (MI) may be triggered by ectopy arising from Purkinje fibers. The role of Purkinje fibers in monomorphic, post-infarction VT has been unclear.
Methods and Results: From a group of 81 consecutive patients with 175 inducible post-infarction VT referred for catheter ablation, 9 patients were identified in whom the clinical VT had a QRS duration ≥ 145 ms. A total of 11 VTs with a QRS duration ≥ 145 ms were induced and mapped in the 9 patients; 9 of the 11 VTs had a right bundle branch block/left axis morphology that mimicked left posterior fascicular VT. The mean VT cycle length was 402±82 ms. Eight of 9 patients had a history of inferior MI involving the left ventricular septum. One patient had an anterior wall myocardial infarction with septal involvement. Mapping during VT demonstrated reentry involving the inferior left ventricular wall. In each of the VTs, a Purkinje potential was present at the exit site of the VT reentry circuit. Single radiofrequency catheter ablation lesions were successful in eliminating these VTs in all patients. No recurrences occurred during a mean follow-up time of 10±9 months.
Conclusion: The Purkinje system may be part of the reentry circuit in patients with post-infarction monomorphic VT, resulting in a type of VT with a relatively narrow QRS complex that mimics fascicular VT.