Ventricular Septal Aneurysm Formation in Perimembranous Ventricular Septal Defect: Longitudinal Echocardiographic Results in 188 Patients

188 Patients with perimembranous (PM) VSD were followed up from a median age of 0.33 (10 to 90. percentile: 0.08 to 3.80 years) for 5.40±5.65 years (median 2.42). Ventricular septal aneurysmal (VSA) transformatian was observed in 105 patients (% 55.85) who were followed up for a mean of 4.94 years (80% between 0.33 and 13.33 years). The range of age at which VSA was first observed in the EkoKG was between 3 days and 22.75 years (median 1.50; and in 80% between 0.15-11.83). The average incidence of VSA transformatian for each age group was 32%. While the mean actuarial probability of formatian of VSA in PM defects calculated by the Kaplan-Meier product method was 38% before age one, this increased to %100 during adolescence. The 95% confidence limits after age 14 was between 75 and 100%. The incidence of spontaneous closure of the defect during the first 6 months after the VSA transformation was 8.33%, and this increased to 41% after 2-3 years and to 50% in those with longer duration than 4 years (95% canfidence limits of the latter were between 31 and 69%). Besides the closure, there was a significant decrease in the diameter of the defect after the VSA transformation, i.e., the mean decrease was 1.84 mm in the year after the VSA was observed, 2.53 mm after 1-3 years, 4.30 mm in more than 3 years, while the decrease in diameter was insignificant in the group without VSA. Regression equations presented showed a yearly decrease of 0.6 mm in diameter of the defect in the group with VSA (p<0.001) while the trend was insignificant in those without VSA. A subaortic fibrous ridge was observed in only one patient, and LV to RA shunt in 4 (%3.81), but these were hemodynamically insignificant.