Ablation of ventricular tachycardia due to a postinfarct ventricular septal defect: Identification and transection of a broad reentry loop

Outer Loop Tachycardia. Introduction: Ventricular tachycardia (VT) after postinfarct ventricular septal defect (VSD) repair has not been well characterized. Methods and Results: A 55-year-old man developed refractory VT after inferior wall infarction and VSD repair. Entrainment demonstrated a broad reentry circuit path (outer loop) between the tricuspid annulus and VSD patch. A series of radiofrequency (RF) lesions transected this path, abolishing VT and producing conduction block between the inferior and superior aspects of the basal right ventricular septum. Conclusion: Some VTs have broad reentry loops requiring ablation by a series of RF lesions across the path to create a line of block. This approach is analogous to that for atrial flutter.