Ventricular Tachycardia Ablation in Patients With Severely Decreased Left Ventricular Ejection Fraction.

Background: Ablation of ventricular tachycardia (VT) is often performed in patients with structural heart disease. Procedural and delayed enhancement cardiac magnetic resonance imaging (DE-CMR) characteristics among patients with very severe cardiomyopathy (CM) and without left-ventricular assist devices (LVAD) have been incompletely described.

Objectives: To examine procedural and imaging characteristics of patients with very severely decreased ejection fractions undergoing VT ablation procedures.

Methods: Consecutive patients with a left ventricular ejection fraction (EF) < 20% and without LVADs who underwent VT ablation were included. A composite outcome of survival free from VT, LVAD, or transplant was examined.

Results: Twenty-seven patients were included (64.1 ± 7.76 years; male n = 23, 88.5%; EF 12.8 ± 3%, LV end diastolic diameter 74 ± 11 mm, ischemic CM (n = 16, 60%), Nonischemic CM (n = 9, 52%), mixed CM (n = 2, 7%)). Twenty-five (93%) patients had failed amiodarone, 9 (33%) had a prior VT ablation, and 13 (48%) underwent ablation for VT storm. Scar was present in 22/23 patients with DE-CMR (intramural [n = 13], endocardial [n = 8], epicardial [n = 2], mixed components [n = 12]). DE-CMR scar corresponded to VT sites of origin in 18/22 patients (82%), excluding one patient with right ventricular VT, two with bundle-branch-reentry VT, and one-non-inducible patient. After 22 ± 19 months, VT occurred in 15/27(56%) patients, death 8/27(30%) and the composite outcome occurred in 22/27(82%) patients.

Conclusion: Patients with very severe cardiomyopathy undergoing VT ablation represent a high risk population, experiencing high rates of VT recurrence and death on midterm follow up. Despite severe remodeling, DE-CMR provides localizing information on the arrhythmia site of origin.