Spontaneous Closure of Isolated Ventricular Septal Defect

The defect closed spontaneously in 64 of 355 (18 %) patients' 1701 years. This rate varied in relation to the age of onset and duration of the foilow-up, as well as with hemodynamic class. The rate of spontaneous closure in those who were followed up since age< 2 years was 50% in the group with small defects (I a) without pulmonary hypertension (PH) in contrast to 29.6 % of those with small defect with PH (II a). On the other hand, in those with abundant left to right shunt, the rate was 15.9. % in those without (I b) and 7.1 % in those with PH (II b). Not considering the pulmonary arteriel pressure, the rate of closure was 37.7 % in those with smail shunt, in contrast to 10.5 % of those with abundant left to right shunt. The age at spontaneous closure of the defect varied between 0.5 to 16.7 years with a median value of 4 years. The range of age at which the defect was still open varied between one month and 13.6 years whose median value was 2.3 years. In order to estimate a more correct incidence of closure according to the hemodynamic classes, the results of only those who could be followed up since age < 1 year were considered. The median age at closure was 0.96 years in group I a, 1.55 years in group II a, 2.17 years in group I b, 5.25 years in group II b. The age at closure was 4.5 years in those with abundant left to right shunt, in contrast to 1.48 years observed in those with small shunts, and this was found to be significant. The rate of closure increased with increasing duration of the follow-up. The difference between those with less and more than 5 years of follow-up was most conspicuous in group II b.