Assessment of the end-systolic pressure-volume relationship in human beings with the use of a time-varying elastance model.
The analysis of left ventricular end-systolic pressure-volume relationships in human beings has been hindered by the lack of a practical method of serial volume assessment and by an imprecise definition of end-systole. Modifications of the end-systolic relationship that have been used to circumvent these problems have included the use of single-point end-systolic pressure-volume ratios, the use of peak systolic pressure/minimum ventricular volume points for end-systolic points, and the use of end-ejection as a marker for end-systole. To assess the correlation between the parameters generated by these modifications with the slope (Emax) and volume intercept (VO) of the end-systolic line as defined by Sagawa's model of time-varying elastance, simultaneous measurement of left ventricular pressure and gated radionuclide volume was made in 26 patients under various loading conditions and pressure-volume diagrams were constructed for each loading condition from 32 simultaneous pressure-volume coordinates. Two pressure-volume diagrams were recorded in 14 patients and three pressure-volume diagrams were recorded in 12 patients. Emax and VO were determined in all patients from the slope and volume intercept of the isochronic pressure-volume line with the maximum time-varying elastance as described by Sagawa's model and were designated true Emax and true VO, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
McKay
R G
RG
Aroesty
J M
JM
Heller
G V
GV
Royal
H D
HD
Warren
S E
SE
Grossman
W
W
D001794:Blood Pressure; D001795:Blood Pressure Determination; D006328:Cardiac Catheterization; D002306:Cardiac Volume; D017023:Coronary Angiography; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000503:physiopathology; D004548:Elasticity; D004912:Erythrocytes; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D009200:Myocardial Contraction; D011877:Radionuclide Imaging; D012044:Regression Analysis; D013318:Stroke Volume; D013599:Systole; D013667:Technetium; D013997:Time Factors
D013667:Technetium