title: Effect of afterload on the left ventricular pressure fall during isovolumic relaxation period in man.
abstract: To assess the effect of afterload on the left ventricular pressure (LVP) fall during isovolumic relaxation period (IRP) in man, we examined the peak (-)dP/dt, (-)dP/dt upstroke pattern in IRP, and time constant (T) in 15 patients [normal (N): 5 valvular heart disease (VHD): 5, dilated cardiomyopathy (DCM): 5]. LVP and echocardiographic internal diameter were measured simultaneously at rest and after about 30 mmHg increment of LV peak systolic pressure (PSP) by drip infusion of angiotensin (20 ng/kg/min). After augmentation in afterload, heart rate (HR) increased slightly in VHD. T increased significantly (p less than 0.05) in N (from 32 +/- 3 to 39 +/- 4 ms) and DCM (from 56 +/- 18 to 72 +/- 12 ms), but not in VHD (from 41 +/- 5 to 46 +/- 8 ms) probably due to increased HR. LV end-systolic dimension had the same trend as T. Although there was no significant change in peak (-)dP/dt in N (from 1937 +/- 385 to 1945 +/- 189 mmHg/s), VHD (from 1521 +/- 210 to 1730 +/- 462 mmHg/s), or DCM (from 814 +/- 143 to 814 +/- 131 mmHg/s), the (-)dP/dt upstroke pattern during IRP became nonexponential in N and more downward convex in VHD or DCM. Thus, these changes of T and (-)dP/dt upstroke pattern suggest the afterload dependence of LVP fall during IRP in normal and diseased hearts.
authors.affiliation: Division of Internal Medicine, Yamaguchi University School of Medicine, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Katayama
authors.forename: T
authors.initials: T
authors.lastname: Kumada
authors.forename: M
authors.initials: M
authors.lastname: Matsuzaki
authors.forename: T
authors.initials: T
authors.lastname: Fujii
authors.forename: M
authors.initials: M
authors.lastname: Kohno
authors.forename: H
authors.initials: H
authors.lastname: Ogawa
authors.forename: M
authors.initials: M
authors.lastname: Ozaki
authors.forename: Y
authors.initials: Y
authors.lastname: Matsuda
authors.forename: R
authors.initials: R
authors.lastname: Kusukawa
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D002311:Cardiomyopathy, Dilated / Q000503:physiopathology; D004452:Echocardiography; D005260:Female; D006339:Heart Rate; D006349:Heart Valve Diseases / Q000503:physiopathology; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D009126:Muscle Relaxation; D010210:Papillary Muscles / Q000503:physiopathology; D013318:Stroke Volume