Catheter ablation of epicardial premature ventricular complexes in patients with and without cardiac scar

BACKGROUND: The left ventricular epicardium is a common site of origin (SOO) among patients with idiopathic premature ventricular complexes (PVCs) undergoing catheter ablation procedures. Less is known about epicardial PVC ablation among patients with myocardial scarring. The objective of this paper is to report on the presence and impact of cardiac scar among patients with epicardial PVCs undergoing ablation procedures. METHODS: In a retrospective analysis, patients with epicardial PVCs and late gadolinium enhanced cardiac magnetic resonance (LGE-CMR) imaging were included. Acute and long-term procedural outcomes were examined and stratified by the presence or absence of cardiac scar. RESULTS: Twenty-nine patients were included (male 17/29(59%), age 55±14 years, ejection fraction 48±12%, PVC burden 25±12%, ischemic cardiomyopathy (CM) n = 3, non-ischemic CM n = 7, PVC induced CM n = 5). The SOO was left ventricular summit (n = 20), great cardiac vein (n = 2), cardiac crux (n = 4), or basal anterolateral epicardium (n = 3). Ablation within the CVS was limited by proximity to the coronary arteries (n = 16), inaccessibility of ablation catheter (n = 5), or elevated baseline impedance (n = 2). LGE-CMR scar was present at the arrhythmia SOO in 14/29(48%) patients. There were no differences in procedural, radiofrequency, or fluoroscopy times between patients with and without scar (p > 0.05). Ablation was successful in 14/29 patients and partially successful in 8/29 patients; the post-ablation PVC burden was 8±10% with no differences among those with or without cardiac scar (P > 0.05). CONCLUSION: Epicardial PVCs may be encountered in patients with and without structural heart disease, with LGE-CMR located at the PVC SOO in almost half of the patients. While LGE-CMR remains a powerful diagnostic modality, its utility in predicting procedural outcomes for epicardial PVC ablation may be limited. Among consecutive patients undergoing ablation of premature ventricular complexes with an epicardial origin, LGE-CMR defined scar was present at the site of origin in approximately 50% of patients.