Incidence and predictors of symptomatic ventricular ectopy in adults with restrictive unrepaired ventricular septal defect: a cardiovascular magnetic resonance imaging study

Abstract Background Despite the increasing prevalence of ventricular septal defect (VSD) in recent decades, long-term arrhythmic outcomes are poorly known due to lack of consistent follow-up in this population. Purpose To evaluate the burden and predictors of symptomatic ventricular ectopy in adult patients with isolated small, unrepaired congenital VSD. Methods 84 patients with isolated unrepaired VSD and available follow-up were retrospectively studied. Patients with additional congenital defects or previous ventricular arrhythmias were excluded. All patients underwent a comprehensive evaluation with contrast-enhanced cardiovascular magnetic resonance (CMR) with left ventricular (LV) and right ventricular (RV) free wall global longitudinal strain (GLS) at the time of enrollment. Over a 5-year follow-up period, ventricular ectopy was documented by Holter monitoring. Results Patients (44% female) had a mean age of 30±12 years, normal biventricular ejection fraction (LVEF 60±4%), restrictive VSD (mean peak gradient 93 mmHg) and a mean left-to-right shunt fraction of 11±4%. Compared to healthy controls, patients with VSD had preserved LV GLS but significantly lower RV free wall GLS (-19.6±2.3 % vs -21.8±2 %, P 0.001). Over a follow-up period of 5 years, symptomatic ventricular ectopy with a 24-hour burden of 5% was documented in 22.6% of the study patients. In multivariable regression analysis, the presence of reduced RV free wall GLS was the strongest predictor of symptomatic ventricular ectopy (HR 0.69, 95% CI 0.54-0.90, P=0.007), followed by shunt fraction severity (HR 1.26, 95% CI 1.05-1.51, P=0.012). Conclusions Adults with congenital isolated restrictive VSD have a high risk of developing symptomatic ventricular ectopy. The presence of reduced RV free wall GLS is a common finding in patients with restrictive VSD and strongly predicts the risk of symptomatic ventricular ectopy. RV free wall GLS may improve risk stratification in adults with restrictive unrepaired VSD.