Search

Advances in echocardiography have enhanced our diagnostic imaging capabilities for congenital heart defects. In addition to improved resolution of two-dimensional images, cardiac hemodynamic assessment is possible with the use of Doppler, color Doppler, and stress echocardiography. Transesophageal echocardiography has allowed intraoperative assessment of cardiac repairs, and fetal echocardiography has allowed development of the field of fetal cardiology. The developing areas of intravascular ultrasonography and three-dimensional echocardiography show promise for the future. Echocardiography continues to revolutionize our ability to diagnose congenital heart defects accurately.

Suprasternal range-gated pulsed Doppler echocardiography was used to evaluate surgical shunt patency in children with cyanotic congenital heart disease and right ventricular outflow obstruction following systemic artery to pulmonary artery anastomoses. Normal patients had laminar Doppler auditory signals and time interval histogram flow patterns because right pulmonary artery turbulence was not present during systole or diastole. Patients with pulmonary valvar stenosis had turbulence during systole only. In all nine postoperative patients with surgical shunts, turbulent systolic and diastolic time interval histograms and abnormal auditory signals were present. A typical shunt murmur was not audible to auscultation in six of the postsurgical patients at the time of the study. Suprasternal range-gated pulsed Doppler echocardiography affords an accurate, safe and simple noninvasive bedside means for confirming shunt patency in patients who have undergone surgical systemic artery to pulmonary artery anastomoses.

Echocardiography is a new noninvasive tool which provides real-time motion visualization of intracardiac structures for the evaluation of anatomy and physiology in patients with congenital heart disease. This paper is presented to acquaint the pediatrician with the utilization and potential of this technique as practiced by pediatric cardiologists. A discussion of principles of physics and instrumentation in echocardiography is followed by a description of normal echocardiographic anatomy. Specific malformations which can be diagnosed reliably by this technique include: hypoplastic left heart syndrome, transposition of the great vessels, tetralogy of Fallot, idiopathic hypertrophic subaortic stenosis, mitral valve prolapse, and pericardial effusion. In addition, the evaluation of patients with atrial septal defects and patent ductus arteriosus is discussed. New advances in instrumentation and their potential impact in pediatric cardiology are reviewed.

The rapid growth in technology after the demonstration of the clinical utility of M-mode echocardiography has led to instruments providing two-dimensional noninvasive ultrasound examinations of the heart and other organs in real time, with high resolution. These techniques now provide images with a wealth of diagnostic, anatomic, and physiologic information. The clinical application of this technology over the past three or four years in many medical centers represents a most profound change in diagnostic pediatric cardiology, providing noninvasively derived information which can be used to decrease the morbidity and mortality of diagnosis and serial follow-up of children with serious congenital heart disease.

The major advances in the capabilities of pediatric cardiologists to evaluate the heart by ultrasound that have occurred in the last 5 years have been reviewed. In addition to the new Doppler methods, the evolution of higher resolution echo techniques have provided a comprehensive means of evaluating the heart noninvasively. This information has relegated catheterization to a more therapeutic arena, leaving ultrasound as the major diagnostic technique for evaluation of congenital heart disease, both before and after birth.

Cine magnetic resonance imaging was used for preoperative and postoperative evaluation of 91 patients with congenital heart disease. Their ages ranged from 6 weeks to 14 years. The quality of study was excellent in 81% of the cases, in which it provided complete documentation of diagnostic features; substantial diagnostic information was provided in another 14%, and the study was nondiagnostic in only 5%. This technique was most useful for evaluating areas of the right ventricle (95%), great arteries (95%), vena cava (94%), and pulmonary venous system (91%). The anatomic delineation of these areas was comparable to that obtained by cineangiography and was superior to echocardiography, especially in postoperative patients. For complex venous anomalies, magnetic resonance imaging provided better anatomic details than did angiography or echocardiography. The capability of multiplanar imaging allows complex angled views through the desired planes of the heart and great vessels. Proper sedation is essential to obtain maximum diagnostic information. Our preliminary experience suggests that this new modality provides excellent anatomic information in infants and children with congenital cardiac defects and will play an increasing role in pediatric cardiac diagnosis.