Scar Mapping Predicts VT Recurrence After Ablation
Can cardiac magnetic resonance (CMR) imaging identify patients with prior myocardial infarction (MI) at risk of recurrence following ablation for ventricular tachycardia (VT)?
This study examined 46 patients with prior MI and performed contrast-enhanced CMR prior to VT ablation and implantation of a cardioverter-defibrillator. Scar characteristics on CMR were compared between patients with versus without recurrence of VT.
Recurrence occurred in 17/46 (37%) patients during a mean follow-up of 32 ± 24 months. Recurrence (vs. none) was associated with larger scar area and larger area of heterogenous tissue on both the endocardium and epicardium (p < 0.05 for each). On multivariable analysis, only endocardial scar extension on CMR was independently associated with recurrence (hazard ratio [HR], 1.3 per 10 cm2; 95% confidence interval [CI], 1.1-1.6; p = 0.03). Patients with a large endocardial scar on CMR (≥65 cm2) had a higher risk of recurrence after complete ablation than those with smaller scars (HR, 5.3; 95% CI, 1.2-25.3; p = 0.04).
Endocardial scar extension on CMR identifies patients with prior MI at increased risk of VT recurrence following ablation.
Identification of patients at risk of recurrence following VT ablation remains challenging. This study of patients with history of MI finds that the presence of large endocardial scar on baseline CMR imaging prior to ablation may identify those at higher risk of recurrence following the procedure. This represents a promising potential approach to improve our selection of patients for these procedures, although the results need to be validated in larger multicenter studies.
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