森 一博¹, 土肥 嗣明¹, 鎌田 政博¹, 清野 佳紀¹, 山本 裕子²

Kazuhiro MORI¹, Tsuguaki DOHI¹, Masahiro KAMADA¹, Yoshiki SEINO¹, Hiroko YAMAMOTO²

¹岡山大学医学部小児科, ²三菱水島病院小児科

¹Department of Pediatrics, Okayma University, School of Medicine, ²Department of Pediatrics, Mitsubishi Mizushima Hospital

キーワード : Right coronary cusp prolapse, Infundibular septal defect, Aortic regurgitation

Thirty patients with an infundibular septal defect (ISD) were evaluated with a two-dimensional echocardiography combined with color flow mapping.
The right coronary cusp prolapse (RCCP) was observed by echocardiography in 17 patients (57%). The percentage agreement of the aortography and the echocardiography was 87% regarding the detection of RCCP. The RCCP in the right ventricle was most visible from the parasternal long-axis view. However, the short axis view was preferable in some cases in which the direction of the prolapse markedly deviated to the outflow or inflow tract of the right ventricle.
Aortic regurgitation (AR) was appeared on the echocardiography of 13 patients (43%). Two cases showed an AR caused by the downward displacement of the right coronary cusp into the outflow tract of the left ventricle rather than the usual alignment of the prolapse into the right ventricle. The percentage agreement of the echocardiographic and aortographic findings regarding the AR was 83%. Two types of RCCP were observed in the echocardiography; a small aneurysmal protrusion and a large box-like herniation. There was apparently no consistent relation between the type of prolapse and the presence of the AR.
The site of ISD was classified into three types on the basis of the echocardiographs; subpulmonary, mid-conus and total-conus defects. Echocardiographic diagnosis of the site of ISD proved to be correct in 16 of the 21 patients (76%) subjected to surgery. However, correct diagnosis was difficult in some of the cases with the large box-like RCCP and the mid-conus defect with a thin walled distal-conus. An aneurysmal membrane, which was believed to represent the process of a natural closure of the defect, was observed in one case with a mid-conus defect.
A two-dimensional echocardiography combined with color flow mapping was very useful for evaluating the ISD. But, there are some cases in which careful observation is necessary for evaluating the RCCP and the site of the defect.