113 TWO-DIMENSIONAL ECHOCARDIOGRAPHY (2D ECHO) IN THE CLOSED CHEST NEWBORN LAMB: METHODOLOGY AND ANATOMICAL OBSERVATIONS

Abstract

Echocardiography has not been applied to investigation of cardiac anatomy or function in newborn experimental animals. Consequently, we have investigated the feasibility of 2D Echo for cardiac imaging in the conscious closed chest lamb.M-mode and 2D Echo studies were obtained from 16 closed-chest recumbant lambs: (age=120 days gestation-term-3 weeks; wt=1.8-8 kg). All cardiac chambers and valves were consistently and successfully imaged by transducer angulation from a left and a right precordial position. Cardiac structures were verified by constrast echo using selective injections of green dye and echocineangiographic studies. In addition, postmortem examinations demonstrated anatomical relationships and the orientation of cardiac chambers to the echo transducer. The ventricles are in a “side by side” position and optimal imaging of the left ventricular “long axis” was obtained from a right thoracic position. Complete study was readily accomplished in 10-20 minutes.We have examined the relevant anatomical relationships and developed a method for chronic M-mode and 2D echo study of the conscious closed chest lamb. It is believed that echo can be used for the investigation of cardiac function in animal models simulating human neonatal cardiopulmonary distress. Such application could potentially expand the role of echocardiography in the human neonate.