Disproportionate shortening of diastolic time and cardiac performance in asymptomatic patients with aortic regurgitation.
OBJECTIVE
Exercise-induced abnormalities of the systolic-diastolic phase proportion and their impact on hemodynamic variables have been investigated only minimally in asymptomatic patients with chronic aortic regurgitation (AR).


METHODS
A group of 33 asymptomatic patients with severe AR and preserved left ventricular (LV) systolic function was studied during incremental exercise, using a combined hemodynamic-radionuclide angiographic approach. The phases of the cardiac cycle were derived with high temporal resolution from the LV time-activity curve. The loss of diastolic time per beat (LDT) was quantified using a regression equation obtained from a healthy control group (n=26). Based on the median LDT at peak exercise, patients were allocated to two groups with LDT < or = 12.4 ms (group A) and LDT > 12.4 ms (group B).


RESULTS
At peak exercise the relative duration of LV diastole was significantly shorter in AR patients than in controls (31.4 +/- 3.0 versus 33.1 +/- 2.4 s/min; p = 0.02) and a significant LDT (12.1 +/- 19 ms; p = 0.003) was observed. Group A patients had a higher peak cardiac output (9.2 +/- 2.0 versus 7.4 +/- 2 l/min/m2; p < 0.03), a longer exercise duration (18 +/- 5 min versus 13 +/- 6 min; p < 0.02) and a lesser extent of mean pulmonary artery pressure rise (27 +/- 10 versus 34 +/- 12 mmHg; p = 0.03) than group B patients.


CONCLUSIONS
Cardiac exercise performance in asymptomatic patients with AR is influenced not only by the ability of the cardiovascular system to favorably redistribute total stroke volume, but also to handle volume overload without changing the systole and diastole phase proportions.
Plehn
Gunnar
G
Department of Cardiology and Angiology, Marienhospital Herne, University of Bochum, Germany. gunnar.plehn@ruhr-uni-bochum.de
Vormbrock
Julia
J
Machnick
Sebastian
S
Meissner
Axel
A
Trappe
Hans-Joachim
HJ
D001022:Aortic Valve Insufficiency / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003971:Diastole; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D011875:Radionuclide Angiography; D013318:Stroke Volume; D016277:Ventricular Function, Left