title: Assessing diastolic function with Doppler echocardiography using a novel index: ratio of the transmitral early diastolic velocity to pulmonary diastolic velocity.
abstract: We developed a novel index to assess left ventricular (LV) relaxation as the ratio of transmitral early diastolic velocity to pulmonary diastolic velocity (E/D ratio). Mixed breed dogs (n=7) were anesthetized and their respiration was controlled. A 3.5-Fr micromanometer-tipped catheter was placed into the left ventricle. Dobutamine (5.0 or 10 microg/kg/min) or esmolol (100 or 500 microg/kg/min) was administered via the cephalic vein. The transmitral flow (TMF) and pulmonary venous flow (PVF) were recorded using transthoracic echocardiography from the apical long-axis view. The heart rate, systolic LV pressure, +dP/dt, and -dP/dt were significantly elevated by dobutamine, but significantly reduced by esmolol. Dobutamine significantly decreased tau, whereas esmolol significantly increased tau. The TMF-derived E and PVF-derived D wave velocities increased significantly with dobutamine, but decreased significantly with esmolol. A significant correlation was detected between the E and D wave velocities (r=0.92). Consequently, the E/D ratio was decreased significantly with dobutamine, and increased significantly with esmolol. Furthermore, the E/D ratio was significantly correlated with -dP/dt (r= -0.64) and tau (r=0.84). Our results suggest that the E/D ratio reflects LV relaxation, and may potentially provide further information on LV relaxation.
authors.affiliation: Department of Small Animal Internal Medicine, School of Veterinary Medicine, Kitasato University, Towada, Aomori, Japan.
authors.forename: Yasutomo
authors.initials: Y
authors.lastname: Hori
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Kanai
authors.forename: Ruriko
authors.initials: R
authors.lastname: Nakao
authors.forename: Fumio
authors.initials: F
authors.lastname: Hoshi
authors.forename: Sei-Ichi
authors.initials: S
authors.lastname: Higuchi
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D003971:Diastole / Q000187:drug effects / Q000502:physiology*; D004280:Dobutamine / Q000494:pharmacology; D004285:Dogs / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D015150:Echocardiography, Doppler / Q000662:veterinary*; D006339:Heart Rate / Q000187:drug effects; D011412:Propanolamines / Q000494:pharmacology
chemical_list: D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D004280:Dobutamine; C036604:esmolol