Determinants of left ventricular filling dynamics: alteration in the Doppler-derived transmitral filling profile with progressive impairment of cardiac function in a dog preparation.
To clarify the factors determining transmitral filling, left ventricular and atrial pressures (LVP and LAP) and Doppler-derived diastolic indices were analysed in six anaesthetized dogs at various right atrial pacing rates during dextran infusion. The relationship of the late to early diastolic peak velocity ratio (A/E ratio) to end-diastolic LVP (LVEDP) showed a quadratic curve concave to the LVEDP axis in five animals (r2 = 0.320-0.588). An elevation in LVEDP up to 25 mmHg accompanied an increase in A/E ratio (ascending limb), and further LVEDP elevation caused its inverse decline (descending limb). Multiple regression analysis indicated that A/E ratio correlated positively with maximal LVP, a-wave LAP and heart rate, and negatively with v-wave LAP in both limbs. The time constant of isovolumic LVP decline, which was prolonged as LVEDP was elevated, was a positive correlate of A/E ratio in the ascending limb, but lost its influence on A/E ratio in the descending limb. An elevation in v-wave LAP must have masked the expected effect of left ventricular relaxation abnormality on A/E ratio in this limb. Thus, the transmitral filling profile did not alter unidirectionally, but returned to that seen before volume loading, with a simultaneous progressive impairment of cardiac function.
Miyaguchi
K
K
First Department of Internal Medicine, Nagoya University School of Medicine, Japan.
Ogawa
S
S
Nomura
H
H
Iwase
M
M
Yokota
M
M
Hayashi
H
H
D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D002304:Cardiac Pacing, Artificial; D003911:Dextrans / Q000008:administration & dosage; D004195:Disease Models, Animal; D004285:Dogs; D015150:Echocardiography, Doppler; D006333:Heart Failure / Q000209:etiology / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology*; D008297:Male; D008943:Mitral Valve / Q000503:physiopathology; D009200:Myocardial Contraction / Q000502:physiology; D012044:Regression Analysis; D016277:Ventricular Function, Left / Q000502:physiology*
D003911:Dextrans