Spontaneous closure of muscular trabecular ventricular septal defect: comparison of defect positions

To evaluate the timing and frequency of spontaneous closure of the muscular trabecular ventricular septal defect (VSD).

We performed a historical cohort study for which 150 patients <3 months of age (median age, 9 days) diagnosed as having a muscular trabecular VSD were selected. Median age at latest follow-up was 2.8 years. Another 32 patients diagnosed after 3 months of age were also reviewed. Using colour Doppler, defects were classified into three groups: anterior, apical and midventricular.

Spontaneous closure occurred in 126 patients (84%): anterior, 36 of 47 (83%); apical, 26 of 31 (84%); and midventricular, 64 of 72 (89%). Multivariate analyses showed a lower frequency of spontaneous closure for patients of age of ≥ 20 days at initial echocardiography [hazard ratio 0.60, 95% confidence interval (CI) 0.39-0.89] and for anterior and apical muscular trabecular VSD (hazard ratio 0.66, 95% CI 0.47-0.95). The prevalence of the midventricular muscular trabecular VSD was significantly lower in patients ≥ 3 months of age at initial echocardiography than in those < 3 months (p = 0.010).

We infer that midventricular muscular trabecular VSD tends to close spontaneously earlier and more frequently than either anterior or apical muscular trabecular VSD.