Circulation, Vol 69, 492-496, Copyright © 1984 by American Heart Association
K Andersen and H Vik-Mo
Twelve healthy men were studied by M mode echocardiography during exercise
to investigate the effect of afterload reduction on left ventricular
function at maximal exertion. They performed two maximal exercise bicycle
tests 4 hr apart while in the semisupine position and were given 20 mg
nifedipine sublingually 30 min before the second test. During the first
test end-systolic dimension decreased (p less than .01) and fractional
shortening increased from rest to peak exercise (p less than .01), while
end-diastolic dimension did not change significantly. At maximal exercise
systolic blood pressure was lower after nifedipine than in the preceding
control test (202 +/- 10 [mean +/- SD] vs 212 +/- 14 mm Hg; p less than
.01), while heart rate was not significantly changed (168 +/- 15 vs 162 +/-
13 beats/min). End- systolic dimension was lower (25.6 +/- 3.3 vs 28.8 +/-
4.2 mm; p less than .01) and fractional shortening higher (50.7 +/- 6.0% vs
45.3 +/- 7.0%; p less than .01) while end-diastolic dimension was unchanged
(52.3 +/- 1.9 vs 52.4 +/- 2.6 mm). Our data indicate increased left
ventricular emptying at maximal exercise after nifedipine, most probably
due to reduction in afterload.
ARTICLES
Increased left ventricular emptying at maximal exercise after reduction in afterload
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