The roentgen spectrum in persistent common atrioventricular canal.

Abstract

With the advent of corrective surgery in congenital heart disease, the differential diagnosis of cardiac abnormalities has become a matter of vital importance to the clinician and the radiologist. The group of lesions classified as persistent common atrioventricular canal defects or endocardial cushion defects represent a broad spectrum of clinical and anatomic abnormalities. In addition, especially with respect to the surgical results, the prognosis depends upon the actual anatomic and functional severity of the anomaly. A brief survey of the literature indicates a marked difference in prognosis between patients with an ostium primum defect in association with a cleft mitral valve and those with an ostium primum defect, a common atrioventricular canal, and a significant ventricular septal defect (Table I). Operative mortality in the first group varies between 7.5 and 22 per cent in several reported series (3–5, 8). If patients in the second group are subjected to primary corrective surgery, however, operative mortality may be as high as 67 per cent. It thus becomes extremely important to determine as accurately as possible the exact anatomic abnormality prior to surgical intervention. Classification We have subdivided our cases in a manner corresponding to the classification of Wakaiand Edwards (10), as follows (Table II): I. Partial form: An ostium primum type of interatrial septal defect in association with a cleft in the anterior leaflet of the mitral valve. Slight shortening of the septal leaflet of the tricuspid valve may be present. Usually there is no ventricular septal defect, although occasionally one which is small and functionally insignificant may be encountered. II. Intermediate form: An ostium primum interatrial septal defect with cleft mitral and tricuspid valves. Small interventricular septal defects are usual, but their size is much smaller than in the complete form. III. Complete form: A continuous cleft through both the anterior mitral and septal tricuspid leaflets in association with an ostium primum interatrial septal defect and a functionally significant ventricular septal defect. IV. Complete or partial forms: Associated pulmonic stenosis. Clinical Material We have seen 43 patients with persistent common atrioventricular canal defects, and in 33 of these, roentgen examinations were adequate. The patients ranged in age from two weeks to fifty-four years (Table III). Plain and Findings The diagnosis of persistent atrioventricular canal is ordinarily made at the time of the clinical examination, including electrocardiography. The electrocardiogram is usually quite characteristic, demonstrating evidence of left axis deviation in association with an rSR or right ventricular hypertrophy pattern in the right precordial leads (2, 7).