Ultrasonography characterization of heart morphology and blood flow of lower vertebrates

Abstract

Echocardiography is an noninvasive technique that utilizes high frequency ultrasound to evaluate structural, functional, and hemodynamic status of the cardiovascular system. With all the inherent potentials of this technique, its application has not been explored on lower vertebrates. 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 identify and characterize cardiac structures and blood flow in lower vertebrates. Specimens studied were Lophius piscatorius, Halobatrachus didactylus, and Bufo bufo. The probe was applied on the ventral middle line over heart chambers. Two-dimensional images were obtained from long and short axis incidences at various levels of cardiac chambers. During each cardiac cycle and for every specimen it was possible to identify the relation between each structure, to measure longitudinal and transversal diameters, to identify blood fluxes, and measure their velocities. The work we describe and discuss in our preliminary experience 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 echocardiography. The effect of the coupling phenomena of contraction and relaxation was also studied through the application of pulsed and color Doppler ultrasound. Two-dimensional and Doppler echocardiography can be easily applied to the study of the anatomy, morphology, and physiology of lower vertebrates. Well defined structures and cardiac chambers were displayed with this noninvasive imaging technique. Echo-Doppler ultrasonography 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 cardiac function.

Fish cardiorespiratory physiology in an era of climate changeThe present review is one of a series of occasional review articles that have been invited by the Editors and will feature the broad range of disciplines and expertise represented in our Editorial Advisory Board.

“…Cotter et al (2008) suggest that ventricular filling is primarily by atrial systole in rainbow trout. This result contrasts with several studies in various teleost and elasmobranch species that demonstrate a biphasic ventricular filling pattern (Lai et al 1990(Lai et al , 1996(Lai et al , 1998(Lai et al , 2004Coucelo et al 1996), consisting of an early direct venous inflow followed by a late phase, which follows the P-wave (atrial contraction). The relative proportion of early to late phase filling (as indicated by the ratio of velocity profiles) suggests that the late phase is at least as large if not greater than the early phase.…”

“…Noninvasive echocardiography (high-frequency sound waves) has proven effective in producing high-resolution two-dimensional images of fish hearts, which have provided information on blood velocity and flow patterns through the heart (including chamber filling patterns; Lai et al 1990Lai et al , 1996Lai et al , 1998Lai et al , 2004Coucelo et al 1996;Cotter et al 2008) and on cardiac chamber shapes and dimensions (including stroke volume and ventricular performance; Davie 1992a, 1992b;Coucelo et al 2000;Claireaux et al 2005). However, this type of imaging necessitates anaesthesia and restraint of the fish.…”

Aspects of the reproductive biology of the toadfish, <i>Halobatrachus didactylus</i> (Schneider, 1801) (Pisces: Batrachoididae)

“…The biology of H. didactylus has received special attention in recent years because of its use as a laboratory animal in toxicological and cardiological experiments (Benítez et al, 1994 a,b;Coucelo et al, 1996). Cárdenas (1977), and Costa et al (1995) examined its feeding habits; and Arias and Drake (1990) studied juvenile distribution in Cádiz Bay.…”

“…Some batrachoid species have traditionally been used as laboratory animals in the field of physiology (Hopkins et al, 1997;Gilmour et al, 1998;Perry et al, 1998;Paert et al, 1999), toxicology (Gutiérrez et al, 1978;Sinovcic et al, 1980;Sarasquete et al, 1982), ethology (Ament et al, 1997;Bass, 1998), neurobiology (Rabbitt et al, 1995;Fine et al, 1996;Hirsch et al, 1998), cardiology (Benítez et al, 1994a,b;Coucelo et al, 1996), and endocrinology (Fine et al, 1996;Knapp et al, 1999). Owing to this, their biology has been extensively studied in most of species.…”

In vivo biofluid dynamic imaging in the developing zebrafish

“…Doppler ultrasound has been used to quantify average vessel blood flow velocities in several species of adult fish (Coucelo et al, 1996; Ho et al, 2002). Despite concerns about the ability to maintain a fixed Doppler angle in such small animals, several cardiac performance parameters have been estimated in the three major heart chambers of adult zebrafish, including blood flow velocity and acceleration/deceleration throughout the cardiac cycle (Ho et al, 2002).…”