Cardiovascular profile of the canine torsades de pointes arrhythmia model assessed by echocardiographic and haemodynamic methods.

ABSTRACT

Chronic atrioventricular block dogs have been established as an in vivo model of drug-induced torsades de pointes arrhythmias. We compared the cardiovascular profile of the canine model with that of sham-operated animals using echocardiographic and haemodynamic methods. In the echocardiographic study, the larger diameters of the left atria, inferior vena cava and left ventricle in end-diastole in addition to greater fractional shortening, end-diastolic volume, stroke volume and ejection fraction were more often detected in the chronic atrioventricular block dogs than in the sham-operated animals. During haemodynamic examination, lower cardiac output and higher pulmonary capillary wedge pressure were detected in chronic atrioventricular block dogs more than in sham-operated animals; however, these changes were within the physiological limits, and the results suggest that the chronic atrioventricular block dogs have a pathophysiological profile of chronic compensated heart failure.