Effects of chronic beta-blockade on rest and exercise hemodynamics in mitral stenosis.
beta-blocker therapy for mitral stenosis is controversial. This study compares right and left heart hemodynamics at rest and supine submaximal exercise in patients (n = 7) receiving chronic beta-antagonists with untreated patients (n = 17) matched for age (mean +/- SD = 51 +/- 12 years) and valve area (0.7 +/- 0.2 cm2/m2). Little benefit was observed with treatment at rest. Although pulmonary capillary wedge pressures (PCWP) were lower during exercise in the beta-blocker group (22 +/- 4 vs. 31 +/- 9 mmHg; P < 0.05), exercise performance was not enhanced and cardiac output response during exercise was reduced (control = 41% increase vs. 12% for beta-blockade). PCWP rose rapidly when diastolic filling periods were < 300 msec in both groups. Pulmonary capillary wedge pressure was found to be a nonlinear functions (P < 0.001) of diastolic filling period (PCWP = 15.9 + 5.84 x 10(5)/dfp2). These data suggest that there is a critical heart rate in patients with mitral stenosis above which hemodynamic compromise rapidly occurs.
Ashcom
T L
TL
Department of Medicine, Brooke Army Medical Center, Fort Sam Houston, Texas, USA.
Johns
J P
JP
Bailey
S R
SR
Rubal
B J
BJ
D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D006328:Cardiac Catheterization; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology; D005260:Female; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D008946:Mitral Valve Stenosis / Q000188:drug therapy* / Q000503:physiopathology; D012146:Rest / Q000502:physiology; D012189:Retrospective Studies; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology; D016278:Ventricular Function, Right / Q000187:drug effects / Q000502:physiology
D000319:Adrenergic beta-Antagonists