Relation of diastolic function and exercise capacity in ischemic left ventricular dysfunction. Role of beta-agonists and beta-antagonists.
The relation between global left ventricular function at rest (evaluated during cardiac catheterization) and exercise capacity was examined in a group of 33 untreated patients with a previous anterior myocardial infarction. The resting ejection fraction (range, 24-68%) correlated poorly with exercise duration (r = 0.47) and did not separate patients with a depressed exercise capacity (exercise duration less than 500 seconds: group A, n = 18) from patients with preserved exercise tolerance (group B, n = 15). The resting left ventricular end-diastolic and end-systolic volume indexes were comparable in groups A and B, but the diastolic pressure-volume relation was shifted upward, and the mean left ventricular pressure during diastolic filling was higher in group A than in group B (19 +/- 8 versus 14 +/- 4 mm Hg; p less than 0.02). The heart rate at maximal exercise was similar in both groups (160 +/- 16 versus 160 +/- 17 beats/min; NS), but heart rate was higher at any given level of exercise in group A than in group B. When 12 patients of group A were treated with xamoterol, a beta 1-adrenoceptor partial agonist, their exercise duration increased by 20 +/- 14% (p less than 0.001), and their maximal exercise heart rate decreased from 158 +/- 16 to 143 +/- 11 beats/min (p less than 0.001). This improved exercise capacity was accompanied by a downward shift of the resting diastolic left ventricular pressure-volume relation and by a decrease in mean left ventricular pressure during diastolic filling.(ABSTRACT TRUNCATED AT 250 WORDS)
Pouleur
H
H
Department of Physiology, University of Louvain, Brussels, Belgium.
Hanet
C
C
Rousseau
M F
MF
van Eyll
C
C
D000318:Adrenergic beta-Agonists / Q000627:therapeutic use*; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000328:Adult; D003327:Coronary Disease / Q000188:drug therapy / Q000503:physiopathology*; D003971:Diastole; D015444:Exercise; D005080:Exercise Test; D005260:Female; D006321:Heart / Q000187:drug effects / Q000503:physiopathology*; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D008875:Middle Aged; D010807:Physical Endurance; D011412:Propanolamines / Q000627:therapeutic use; D012146:Rest; D013997:Time Factors; D017307:Xamoterol
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D017307:Xamoterol