Risk Stratification of Patients With Apparently Idiopathic Premature Ventricular Contractions

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).The role of CMR imaging in patients with frequent PVCs and otherwise negative diagnostic workup is uncertain.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.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).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.