Cardiac magnetic resonance imaging in right ventricular outflow tract arrhythmia: a retrospective analysis from a tertiary care centre in South India

Abstract

Introduction Arrhythmia arising from right ventricular outflow tract (RVOT) is the most common cause of idiopathic ventricular arrhythmia. Previous studies involving cardiac magnetic resonance imaging (MRI) in these patients are known to show abnormalities in up to 60% of patients. Methodology This was a retrospective descriptive analysis of patients having idiopathic RVOT arrhythmia who underwent cardiac MRI between January 2010 and December 2020. Clinical and demographic details were recorded from the electronic medical records and cardiac MRI of all patients were reviewed. Results Among 214 patients with RVOT arrhythmia, 64 underwent cardiac MRI. A total of 41 patients, who did not have any abnormality on baseline echocardiogram were included in the study. There was male preponderance (56.1%), with median age of 43 years. About 43.9% had syncope. Twenty-four-hour Holter study revealed a premature ventricular complex (PVC) burden of 26.3 ± 11.7%. MRI showed structural abnormalities in 51.2% of patients, which commonly included RV sacculations and aneurysms. Late gadolinium enhancement (LGE) was seen in six patients, which was mostly seen in RV free wall. Right ventricular (RV) systolic dysfunction was evident in 29.3%. About 9.8% fulfilled the criteria for arrhythmogenic RV cardiomyopathy (ARVC). Out of 23 patients with baseline abnormalities on ECHO, 87% had structural abnormalities on MRI, and 43.5% fulfilled the criteria for ARVC. Conclusions Additional imaging by cardiac MRI helps to identify structural abnormalities in 51.2% of patients with RVOT arrhythmias, even with normal baseline echocardiogram and electrocardiogram (ECG). It is useful tool to rule out ARVC in this subset of patients, and can help in increasing the diagnostic yield in the early stages.