RESUMO
This study was designed to determine the incidence, types of the defects and the rate of spontaneous closure of the small ventricular septal defect (VSD) in infants who were born at Ramathibodi Hospital during the one year period April 1, 1991 to March 31, 1992. The diagnosis was confirmed by 2D-echocardiogram and Doppler and color flow imaging. RESULT: During the study period, the 15 infants diagnosed with small VSD, an incidence of 1.95 per 1,000 livebirths. The male to female ratio was 9 to 6. There were 11 muscular and 4 membranous VSD. Small VSD had a maximal diameter of 3 mm. of less. Spontaneous closure occurred in 9 to 15 (60%) during 6 months follow-up. The small muscular VSD spontaneously closed in 9 of 11 (82%) patients. CONCLUSION: This data supports the previous studies that the rate of spontaneous closure of small VSD is high and the muscular defect has a higher incidence of spontaneous closure.