Effects of changes in atrioventricular gradient and contractility on left ventricular filling in human diastolic cardiac dysfunction.
The factors responsible for abnormalities in diastolic filling indexes as assessed by noninvasive testing in human beings have been extensively studied but are not completely understood. We therefore investigated left ventricular diastolic filling indexes by radionuclide angiography during right atrial pacing simultaneously with assessment of a directly measured left atrioventricular gradient and a time constant of isovolumic relaxation in 11 patients with hypertension and diastolic dysfunction. Loading conditions were altered with nitroprusside and phenylephrine, and contractility was improved by dobutamine infusion. The maximum left atrioventricular gradient at constant heart rates was determined by loading conditions and was not significantly affected by increases in contractility or an improvement in isovolumic relaxation rate. The peak filling rate according to radionuclide angiography was highly dependent on the atrioventricular gradient and was not affected by enhancement of the isovolumic relaxation rate.
Lenihan
D J
DJ
Department of Internal Medicine, University of Cincinnati, OH 45267-0542, USA.
Gerson
M C
MC
Dorn
G W
GW
Hoit
B D
BD
Walsh
R A
RA
D000328:Adult; D000959:Antihypertensive Agents / Q000627:therapeutic use; D016275:Atrial Function; D002316:Cardiotonic Agents / Q000627:therapeutic use; D003326:Coronary Circulation; D003971:Diastole; D004280:Dobutamine / Q000627:therapeutic use; D006331:Heart Diseases / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000150:complications; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects; D009599:Nitroprusside / Q000627:therapeutic use; D010656:Phenylephrine / Q000627:therapeutic use; D011875:Radionuclide Angiography; D016276:Ventricular Function; D016277:Ventricular Function, Left
D000959:Antihypertensive Agents; D002316:Cardiotonic Agents; D009599:Nitroprusside; D010656:Phenylephrine; D004280:Dobutamine