Assessing LV Diastolic Function with Pulmonary Venous Flow Profiles in Dogs

Abstract

We investigated the utility of the pulmonary systolic velocity to the pulmonary diastolic velocity (S/D ratio) as a measure of left ventricular (LV) diastolic function in dogs. Six beagles were anesthetized and respiration was controlled. A 3.5-Fr micromanometer-tipped catheter was placed into the LV. Dobutamine or esmolol was administered via the cephalic vein. The transmitral flow (TMF) and pulmonary venous flow (PVF) velocities were measured using transthoracic echocardiography. The ratios of the E/A ratio and S/D ratio were calculated. The heart rate, systolic left ventricular pressure, +dP/dt, and -dP/dt were increased significantly with dobutamine, but significantly decreased with esmolol. The TMF velocities were elevated significantly with dobutamine, but decreased significantly with esmolol. The PVF velocities were elevated significantly with dobutamine, but not changed with esmolol. The -dP/dt and LVEDP were significantly correlated with the S/D ratio (r²=0.44, r²=0.22; respectively), but not with the E/A ratio (r²=0.05, r²=0.01; respectively). Our results suggest that the S/D ratio provide additional information to investigate LV relaxation in healthy dogs.