M-Node Echocardiographic Assessment of D-Transposjtjon of the Great Arteries and Associated Defects

Abstract

INTRODUCTION:

M-mode echocardiography has proven to be a reliable means for the diagnosis of d-transposition of the great arteries (8, 5). The M-mode echo diagnostic criteria are the demonstration of: (1) an anterior aorta, identified by delayed opening of its semilunar valve compared to the pulmonary valve, and (2) the aorta being situated rightward and anteriorly vis-a—vis the posterior pulmonary artery.

MATERIAL AND METHODS:

Forty—one patients with d-transvositjon of the great arteries were studied prior to, and 73 following Mustard operation and correction of associated lesions. Seventeen patients had sequential pre- and postoperative echocardio— graphic and cardiac catheterization studies. The echocardiograrns were obtained within 24 hours of cardiac catheterization. Hemodynamic data were obtained at cardiac catheterization using fluid—filled catheters and Statham gauge pressure transducer prior to the angio-graphic studies. Right ventricular angio— graphic volumes and ejection• fractions were obtained in 18 patients using Simpson’s method (7). Superior vena caval, right ventricular and left ventricular selective cineangiograms were also obtained.

RESULTS:
Preoperative Studies

Forty-one patients with d-transposition of the great arteries were studied prior to the Mustard operation and correction of associated lesions. The echocardiographic and hemodynamic data of these patients are presented in Table 1. The age ranged between 1 day and 13 years (mean 3.2±4.2 years). Preoperatively, the PEP/RVET ratio was > 0.50 in only one patient; postoperative1y,.the ratio was 0.50 in 4 patients and in 2 of these hemodynamically significant tricuspid regurgita‘ don and angiographically estimated reduced ejection fraction (0 . 50) was noted.

DISCUSSION:

This study confirms that M-mocle echocard iography is a reliable means for diagnosing d-transposed great arteries. The transducer angulation (from the standard 4th intercostal parasternal space) required to detect the transp osed aorta is rightward and anterior (toward the right shoulder) from the posterior vessel, as opposed to an anterior and leftward angulation required to detect the anterior vessel (pulmonary Artery) in normally related great vessel.In summary, M-mode echocardiography prov ides not only a reliable means of diagnosing d-transposition of the great arteries, but is also useful for assessing the presence of associated lesions. Changing hemodynamic parameters in patients with transposition of the great arteries can be followed before and after the Mustard operation by longitudinal echocardiographic ass essment -