Differences between the Filling Velocities of the Left and Right Heart Ventricle in Racing Pigeons (Columba livia F. Domestica) and the Influence of Anesthesia with Isoflurane

Abstract

The ventricular filling velocities during diastole and the influence of isoflurane anesthesia on these blood flow velocities of the racing pigeon (n = 43) are evaluated by pulsed-wave (PW) Doppler sonography. Sonographic examination demonstrates an early passive ventricular (E wave) and late active (A wave) ventricular filling. The results indicate differences between the two heart ventricles. Especially, the E wave velocity of the right heart is significantly lower than in the left heart, which is explained by the crescent-shaped cavity of the right ventricle around the left ventricle. The faster active filling velocities are significantly influenced by heart rate in conscious birds. Anesthesia with isoflurane leads to a significant decrease of the diastolic blood flow velocities, and the A wave velocities of both ventricles are especially influenced. Anesthesia with isoflurane induces a high incidence of insufficiencies of the left atrioventricular valve in the preejection period. These observations indicate that a contraction of the left ventricle myocardium is important for a complete valvular closure and for normal functioning of this heart valve. The effective closure of the right atrioventricular muscle valve in anesthetized pigeons supports the observation of the fast innervation of this muscle valve via a direct connection to the right atrium.

Color Flow Doppler Echocardiography in Healthy Racing Pigeons (Columba livia f. domestica) and the Evidence of Physiological Blood Flow Vortex Formations

“…The diastolic blood flow is characterized by an early or passive diastolic filling (E wave in pulse wave Doppler image; descending part of T wave in ECG) and an active filling during the atrial contraction (A wave in pulse wave Doppler image) or fused (EA wave in pulse wave Doppler image) in higher heart rates [ 3 , 4 , 10 ] and a systolic blood flow through the aorta and pulmonary artery (ascending part of S wave to descending part of T wave of ECG). This general blood flow was well visualized for the pigeons with color flow imaging in our study and is already described in the literature for other bird species [ 3 , 4 , 14 , 23 , 30 ]. The generally valid color coding used in small animal medicine, the diastolic blood flow color-coded in red, and the systolic blood flow in blue could also be used in the pigeons in the used acoustic windows [ 10 ].…”

“…The significant differences between the PRF settings in systole and diastole to visualize the blood flow in our investigations illustrate this necessity. An initial PRF setting can be selected according to the blood flow velocity specifications in the literature for pigeons depending on heart rate or anesthesia used [ 21 , 22 , 23 , 31 ].…”

“…However, in our study the insufficiency of the left AV valve in the preejection period could be visualized in two birds with this technique. The importance of muscle contraction of the left ventricle and the influence of anesthesia on the function of the left AV valve were previously described and discussed by Legler et al [ 23 ]. Anesthesia with isoflurane leads to an AV valve insufficiency in the preejection period in 93% of pigeons, which was diagnosed with color Doppler sonography [ 23 ].…”

“…Doppler flow imaging is an important tool in human and small animal cardiology to visualize and measure blood flow in the heart, to detect turbulent flow, and to diagnose pathological conditions [ 10 , 11 , 12 , 13 ]. In avian medicine Doppler sonographic techniques are also used to visualize and estimate blood flow in the heart [ 3 , 4 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. In particular, color flow Doppler imaging is used in avian medicine to visualize heart valve insufficiencies, aneurysm, and atrial or ventricular septal defects [ 3 , 4 ].…”

“…In particular, color flow Doppler imaging is used in avian medicine to visualize heart valve insufficiencies, aneurysm, and atrial or ventricular septal defects [ 3 , 4 ]. Small valvular regurgitations are easier to diagnose in color flow sonography compared to pulse wave (PW) or continued wave (CW) Doppler imaging [ 23 ]. In color flow images velocity information is combined with anatomical information.…”