Predictors of Myocardial Fibrosis Detected by CMR in Patients With Idiopathic PVCs

BACKGROUND: Premature ventricular contractions (PVCs) are a frequent electrocardiographic finding in routine medical practice, and 16% of the patients with idiopathic PVCs may have underlying heart disease. OBJECTIVE: We analyzed the correlation between the morphology of the PVCs and the myocardial scarring identified by cardiac magnetic resonance (CMR), together with the impact of late gadolinium enhancement (LGE) on the need for ablation. METHODS: Ninety-four patients (median age 56 years) with frequent PVCs (> 500 PVCs on 24 h) and a structurally normal heart were referred for comprehensive CMR. The patients were followed for 12 months. Patients were referred for ablation if they were symptomatic in the context of frequent PVCs. RESULTS: The prevalence of LGE identified by CMR was higher among males (OR 5.506 (2.092-14.49) p < 0.05), with an age ≥ 50 years (OR 1.047 (1.015-1.08), p < 0.05) and a higher PVC burden (OR 1.922 (1.723-1.976), p < 0.05). Additionally, patients with PVCs with a LBBB inferior axis had four times higher risk of exhibiting LGE (OR 4.09 (1.584-10.565), p < 0.05). In multivariate analysis, age (OR 1.059 (1.019-1.099), p < 0.05) and a LBBB inferior axis (OR 4.605 (1.472-14.404), p < 0.05) were independently associated with the presence of LGE. CONCLUSION: Patients with PVCs and apparently, structurally normal heart present myocardial scarring identified by CMR in 71.23% of cases. PVCs with LBBB inferior axis pattern, age ≥ 50 years and male sex are associated with the presence of LGE on CMR. In multivariate analysis, age and LBBB inferior axis were independently correlated with the presence of LGE.