New insight into left ventricular function in tricuspid atresia after total cavopulmonary connection: a three-dimensional echocardiographic study

BackgroundIn patients with tricuspid atresia palliated by construction of a total cavopulmonary connection, both pulmonary and systemic circulations depend on the performance of the dominant left ventricle. When estimating the volume of such ventricles using cross-sectional echocardiography, it is necessary to make assumptions concerning the geometry of the ventricular shape. This is avoided by three-dimensional echocardiography, which provides direct volumetric data. Our purpose was to apply this new method to quantify left ventricular volumes and function in patients with tricuspid atresia after construction of a total cavopulmonary connection.MethodsWe studied ten patients (median age: 8 years) with tricuspid atresia who had undergone a total cavopulmonary connection, comparing them with 10 normal children matched for age, sex and size. The three-dimensional echocardiography was performed with electrocardio graphic and respiratory gating. A new transthoracic integrated probe designed for small children was used with a rotational scanning increment of 3°. The 60 slices obtained from the ventricular cavity were stored and formatted in a commercial system (TomTec®). End-diastolic and end-systolic volumes, stroke volume and ejection fraction were calculated after manual tracing of the endocardial surfaces. The volumes were indexed to the body surface area.ResultsAs seen in the reconstructions, the dominant left ventricle in tricuspid atresia had a spherical shape, whereas the normal left ventricle is oblong. The left ventricular volumes and function in tricuspid atresia were 54±4 ml/m2(end-diastolic volume), 28±3 ml/m2(end-systolic volume), 26±7 ml/m2(stroke volume) and 48±6% (ejection fraction). These volumes were not different from those obtained in the controls (p = NS). The left ventricular stroke volume and ejection fraction in 10 patients with tricuspid atresia were lower than those calculated for the controls (p < 0.05).ConclusionsThree-dimensional echocardiography provides a quantitative insight into the pathophysiologic function of the dominant left ventricle in tricuspid atresia after construction of a total cavopulmonary connection.