Clinical significance of myocardial scar in patients with frequent premature ventricular complexes undergoing catheter ablation

BACKGROUND Frequent premature ventricular complexes (PVCs) can result in PVC-induced cardiomyopathy (PICM). Scarring has been described in patients with frequent PVCs in the absence of apparent heart disease and in patients with known cardiomyopathy.OBJECTIVE The purpose of this study was to determine the impact of focal myocardial scarring as detected by cardiac magnetic resonance imaging (CMR) on PICM, procedural outcomes, and recovery of left ventricular function in patients with frequent PVCs.METHODS A total of 351 consecutive patients (181 men; age 53 +/- 15 years; ejection fraction [EF] 51% +/- 12%) with frequent PVCs referred for ablation were included. CMR was performed in all patients before the ablation procedure. A >= 10% increase in EF or normalization of a previously abnormal EF was defined as evidence of PICM.RESULTS Myocardial scarring was present in 134 of 351 patients (38%); 66 of 134 patients (49%) with scarring and 54 of 217 patients (25%) without scarring had improvement or normalization of EF after ablation. The presence of myocardial scarring, PVC burden >22%, male sex, asymptomatic status, and PVC QRS width >150 ms were associated with PICM by univariate analysis (P <.01 for all). The presence of scar was independently associated with PICM (odds ratio 2.2; 95% confidence interval 1.3-3.7; P < .005) . The success rate of PVC ablation was lower in patients with scarring than in patients without focal scarring (mean 70% vs 82%; P <.01).CONCLUSION Focal scar defined by CMR is independently associated with PICM. Although ablation outcomes are worse in the presence of scarring, EF recovery can occur in most of these patients after ablation.