Catheter ablation of ventricular tachycardia after left ventricular reconstructive surgery for ischemic cardiomyopathy

Background: After surgical ventricular restoration (SVR) for ischemic cardiomyopathy, ventricular tachycardias (VTs) are an important reason for postoperative morbidity and mortality.

Objective: The purpose of this study was to elucidate the VT substrate, VT characteristics, and outcome of radiofrequency catheter ablation (RFCA) in patients with VT after SVR.

Methods: Twelve (3%) of 416 patients referred for RFCA for VT after myocardial infarction in three centers had undergone SVR. After induction of VT, left ventricular (LV) electroanatomical mapping was performed. Ablation target sites were identified by entrainment, substrate, and/or pace mapping.

Results: Four (33%) patients presented within the perioperative period with incessant VT, and eight (67%) presented with incessant or recurrent VT late after SVR (VT cycle length 453 ± 102 ms). The region of surgical scar was identified by electroanatomical mapping in 11 patients. Twenty-eight VTs (cycle length 384 ± 95 ms) were induced. The VT exit was bordering the surgical scar in 20 (71%) VTs, of which 15 were at the septal side. All VTs were abolished in five patients: in four only the clinical VTs were abolished, and in one reinducibility was not tested. In two patients, ablation failed after which surgical ablation was performed successfully. During follow-up, three (25%) patients died (nonarrhythmic deaths); all had presented early after SVR. Two (17%) experienced recurrent VT.

Conclusion: VT after LV SVR seems to have a bimodal presentation; one-third presented with incessant VT in the acute postoperative phase and had a high mortality. Two-thirds presented late after SVR; in these patients RFCA is usually effective. Successful ablation sites are frequently located at the border of surgical scars and patch material.