ULTRASONOGRAPHY CHARACTERIZATION OF HEART MORPHOLOGY AND BLOOD-FLOW OF LOWER-VERTEBRATES

Echocardiography is an noninvasive technique that utilizes high freque ncy ultrasound to evaluate structural, functional, and hemodynamic sta tus of the cardiovascular system. With all the inherent potentials of this technique, its application has not been explored on lower vertebr ates. The objective of our work was to apply ultrasonography technique , with an available commercial equipment (Echo camera - Aloka SSD 830 and Toshiba using probes of 5 and 7.5 MHz frequency emission) and to i dentify and characterize cardiac structures and blood flow in lower ve rtebrates. Specimens studied were Lophius piscatorius, Halobatrachus d idactylus, and Bufo bufo. The probe was applied on the ventral middle line over heart chambers. Two-dimensional images were obtained from lo ng and short axis incidences at various levels of cardiac chambers. Du ring each cardiac cycle and for every specimen it was possible to iden tify the relation between each structure, to measure longitudinal and transversal diameters, to identify blood fluxes, and measure their vel ocities. The work we describe and discuss in our preliminary experienc e and data concerning the ultrasound study of some lower vertebrates. The cardiovascular apparatus of the different species we studied was a dynamic, phasic, and efficient contraction and relaxation mechanism. The phenomena could be well documented with two-dimensional echocardio graphy. The effect of the coupling phenomena of contraction and relaxa tion was also studied through the application of pulsed and color Dopp ler ultrasound. Two-dimensional and Doppler echocardiography can be ea sily applied to the study of the anatomy, morphology, and physiology o f lower vertebrates. Well defined structures and cardiac chambers were displayed with this noninvasive imaging technique. Echo-Doppler ultra sonography is a reliable technique in these lower vertebrate specimens , to study cardiac structure and kinetics, and to identify and measure blood flow velocity. It can be used as an experimental model for card iac function. (C) 1996 Wiley-Liss, Inc.