Deductive Echocardiographic Analysis in Infants with Congenital Heart Disease

Abstract

SUMMARYA step-by-step approach to cardiac diagnosis utilizing a chest X-ray and echocardiography is described and used to study a normal infant and six infant patients with angiocardiographically-proven complex congenital heart malformations.The heart is divided into three major anatomical segments in order to localize the atrial and ventricular chambers and determine the relationship of the great arteries. The atrial chambers are localized by noting the position of the liver on the X-ray. The right atrium is on the same side as the liver with few exceptions. The ventricular chambers are localized by echocardiographically identifying the tricuspid and mitral valves. They are a part of the morphologically right and left ventricles, respectively. As a general rule, the atrioventricular valve whose anterior leaflet is continuous with the posterior margin of a semilunar valve is the mitral valve. The atrioventricular valve whose anterior leaflet is not continuous with a posterior semilunar valve margin is the tricuspid valve. When the tricuspid valve is to the right of the mitral valve, the ventricles are in their normal positions (ventricular d-loop); when it is to the left, the ventricles are inverted (ventricular 1-loop). The relationship of the great arteries is determined by echocardiographically identifying the semilunar valves and noting their positions relative to each other, the interventricular septum and the ventricular chambers. In a ventricular d-loop, the aortic valve is usually to the right of the pulmonary valve. In a ventricular l-loop, the opposite is true. As much as a 17% error may exist when transposition of the great arteries is a component of the malformation. Therefore, as additional aids in semilunar valve identification the R-C intervals of the valves (interval between R wave of electrocardiogram and valve closure on echogram) and outside diameters of the valve roots are measured. Usually the R-C interval is longer and, in the absence of pulmonary stenosis, the outside diameter greater for the pulmonary valve. The segmental diagnoses are then combined to obtain the "'type" of heart, and a careful search is made for associated defects.Using this approach, the positions of the atrial and ventricular chambers and the relationship of the great arteries were accurately determined in the six complex cardiac malformations studied. Additional Indexing Words:Cardiac segmental diagnosis Ultrasound cardiography Noninvasive techniquesTransposition of the great arteries IN AN EARLIER REPORT the atrioventricular and semilunar valves were used as ultrasonic landmarks to obtain an echocardiographic profile of the heart and its great arteries in the normal neonate.' Since that study, additional uses of the atrioventricular and semilunar valves have resulted in our being able to predict the character of the internal cardiac From the Cardiology Section, Norton-Children's Hospital, and

Corrected transposition of great vessels and Ebstein's anomaly of tricuspid valve. Echocardiographic findings.

“…The atrioventricular valves were identified by their relation to semilunar valves as described by Solinger et al (1974). The posterior, left atrioventricular valve (tricuspid) was easily recorded in the 3rd and 4th intercostal spaces in a wide area from the left sternal border to the left midclavicular line.…”

Left and right ventricular systolic time intervals in the newborn. Usefulness and limitation in distinguishing respiratory disease from transposition of the great arteries.

“…While these findings may suggest the diagnosis of transposition, they are very subjective, and more objective criteria for identifying the great arteries have been sought. Solinger et al (1973Solinger et al ( , 1974 have emphasised that the pulmonary valve, regardless of its location, closes after the aortic valve. Our results support this finding; if one semilunar valve closed after the other, it was, with one exception, the pulmonary valve.…”

Echocardiographic identification of aorta and main pulmonary artery in complete transposition.

“…But in 21 per cent of cases of complete transposition of the great arteries this relation does not hold (Nadas and Fyler, 1972). Attempts have been made to distinguish the great arteries with M-mode echocardiography by comparing systolic time intervals (Solinger et al, 1974;Fouron et al, 1976) or the outside diameters of the great artery roots (Solinger et al, 1974) or, most recently, byusing contrast echocardiography (Mortera et al, 1977). Measurement of electromechanical systole, ventricular ejection times, and pre-ejection periods allows the great arteries to be differentiated, but only when the pulmonary vascular resistance is low (Solinger et al, 1974;Fouron et al, 1976).…”

“…Attempts have been made to distinguish the great arteries with M-mode echocardiography by comparing systolic time intervals (Solinger et al, 1974;Fouron et al, 1976) or the outside diameters of the great artery roots (Solinger et al, 1974) or, most recently, byusing contrast echocardiography (Mortera et al, 1977). Measurement of electromechanical systole, ventricular ejection times, and pre-ejection periods allows the great arteries to be differentiated, but only when the pulmonary vascular resistance is low (Solinger et al, 1974;Fouron et al, 1976). Though the outside diameter of the pulmonary artery root has been reported to be larger than that of the aortic root in normal infants (Solinger et al, 1973;Hagan et al, 1973), this observation is likely to be of little practical value in differentiating the great arteries in complete transposition of the great arteries, where in those with no ventricular septal defect or pulmonary stenosis Shaher (1973) found them to be equal in 54 per cent.…”