Concealed structural heart disease discovered at cardiac magnetic resonance in patients with ventricular extrasystoles from ventricular outflow tract and apparently normal hearts

Background: Outflow tract (OT) premature ventricular contractions (PVCs) are commonly found in clinical practice; in most cases, PVCs are benign and observed in structurally normal hearts, not requiring any therapeutic intervention. In this study, we therefore sought to evaluate with cardiac magnetic resonance (CMR) patients with PVC and apparently normal heart at echocardiographic examination, in order to identify possible substrates linked with higher prevalence of arrhythmias or structural heart disease. Methods: Thirty-three consecutive patients with frequent PVCs originating from the ventricular OT (right and left) were enrolled in the study and assessed by echocardiography and CMR. All patients had normal baseline electrocardiogram. Results: CMR showed structural changes in 5 patients out of 33; in 3 cases, areas of fibrosis limited in one case to the middle basal segments of the interventricular septum and in two patients to the middle basal segments of the inferior-lateral wall were found. In 2 other cases, however, late gadolinium enhancement showed significant anomalies characterized in one patient by extensive areas of subepicardial fibrosis of the left ventricle, suitable with arrhythmogenic left dominant dysplasia; in another patient, a marked trabeculation of left ventricular medium apical segments suitable with non-compaction myocardium was present. Conclusions: CMR may identify cases of structural heart disease in subjects with OT PVCs and apparently normal electrocardiogram and echocardiogram examinations. A preliminary screening with CMR may be considered before any further invasive electrophysiology assessment and therapeutic planning.