Surcharge volumétrique cardiaque chez le lapin en croissance par fistule artério-veineuse chronique Evaluation d'un modèle original

Abstract

A heart volume overload model was developed in male New Zeland rabbit nine weeks old, using femorofemoral or jugulo-carotid fistulae, producing 50% increase of the mean cardiac output. An evaluation was performed after 2 and 11 weeks. It was evaluated by dimensional echocardiogram and doppler system flow measurement at the aorta ring, angiography and right cardiac pressure recording. This hemodynamic analysis was completed by a heart and fistulae histopathological study. In some volume overload cases, an increasing volume index parameter was described. Two weeks later an increase of the cardiac frequency and a dilatation of the aorta ring were observed but the stroke volume remained unchanged. 11 old weeks fistula animals presented similar frequency and stroke volume. So, the heart compensatory mechanisms varied with the age of the rabbit. The right catheter and cardiac angiography were not useful for ventricular volume overload estimation. Histopathological study showed parenchymal changes and alveolo capillar congestion. An increase of the heart weight/body weight ratio was described.

When analysed by ultrasound and blood flow measurement, data were similar to those obtained by invasive pressure recordings or by dilution system.

An experimental model of overload volume in rabbit with non invasive recording methods (bidimensionnal ultrasound and doppler system) can be proposed.