Risk Stratification of Patients With Apparently Idiopathic Premature Ventricular Contractions: A Multicenter International CMR Registry

OBJECTIVES:This study investigated the prevalence and prognostic significance of concealed myocardial abnormalities identified by cardiac magnetic resonance (CMR) imaging in patients with apparently idiopathic premature ventricular contractions (PVCs). BACKGROUND:The role of CMR imaging in patients with frequent PVCs and otherwise negative diagnostic workup is uncertain. METHODS:This was a multicenter, international study that included 518 patients (age 44 ± 15 years; 57% men) with frequent (>1,000/24 h) PVCs and negative routine diagnostic workup. Patients underwent a comprehensive CMR protocol including late gadolinium enhancement imaging for detection of necrosis and/or fibrosis. The study endpoint was a composite of sudden cardiac death, resuscitated cardiac arrest, and nonfatal episodes of ventricular fibrillation or sustained ventricular tachycardia that required appropriate implantable cardioverter-defibrillator therapy. RESULTS:Myocardial abnormalities were found in 85 (16%) patients. Male gender (odds ratio [OR]: 4.28; 95% confidence interval [CI]: 2.06 to 8.93; p = 0.01), family history of sudden cardiac death and/or cardiomyopathy (OR: 3.61; 95% CI: 1.33 to 9.82; p = 0.01), multifocal PVCs (OR: 11.12; 95% CI: 4.35 to 28.46; p < 0.01), and non-left bundle branch block inferior axis morphology (OR: 14.11; 95% CI: 7.35 to 27.07; p < 0.01) were all significantly related to the presence of myocardial abnormalities. After a median follow-up of 67 months, the composite endpoint occurred in 26 (5%) patients. Subjects with myocardial abnormalities on CMR had a higher incidence of the composite outcome (n = 25; 29%) compared with those without abnormalities (n = 1; 0.2%; p < 0.01). CONCLUSIONS:CMR can identify concealed myocardial abnormalities in 16% of patients with apparently idiopathic frequent PVCs. Presence of myocardial abnormalities on CMR predict worse clinical outcomes.