Exercise hemodynamics and myocardial metabolism during long-term beta-adrenergic blockade in severe heart failure

J Am Coll Cardiol. 1991 Oct;18(4):1059-66. doi: 10.1016/0735-1097(91)90767-4.

Abstract

Hemodynamics and myocardial metabolism at rest and during exercise were investigated in 21 patients with heart failure. The patients were evaluated before and after long-term treatment (14 +/- 7 months) with the beta-adrenergic blocking agent metoprolol. Clinical improvement with increased functional capacity occurred during treatment. Maximal work load increased by 25% (104 to 130 W; p less than 0.001). Hemodynamic data showed an increased cardiac index (3.8 to 4.6 liters/min per m2; p less than 0.02) during exercise. Pulmonary capillary wedge pressure decreased at rest (20 to 13 mm Hg; p less than 0.01) and during exercise (32 to 28 mm Hg; p = NS). Stroke volume index (30 to 39 g.m/m2; p less than 0.006) and stroke work index (28 to 46 g.m/m2; p less than 0.006) increased during exercise and long-term metoprolol treatment. The arterial norepinephrine concentration decreased at rest (3.72 to 2.19 nmol/liter; p less than 0.02) but not during exercise (13.2 to 11.1 nmol/liter; p = NS). The arterial-coronary sinus norepinephrine difference suggested a decrease in myocardial spillover during metoprolol treatment (-0.28 to -0.13 nmol/liter; p = NS at rest and -1.13 to -0.27 nmol/liter; p less than 0.05 during exercise). Coronary sinus blood flow was unchanged during treatment. Four patients produced myocardial lactate before the study, but none produced lactate after beta-blockade (p less than 0.05). There was no obvious improvement in a subgroup of patients with ischemic cardiomyopathy. In summary, there were signs of increased myocardial work load without higher metabolic costs after treatment with metoprolol.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic beta-Antagonists / therapeutic use*
  • Cardiomyopathy, Dilated / drug therapy*
  • Energy Metabolism / drug effects
  • Epinephrine / blood
  • Exercise / physiology*
  • Female
  • Heart Failure / drug therapy*
  • Hemodynamics / drug effects
  • Hemodynamics / physiology*
  • Humans
  • Male
  • Metoprolol / therapeutic use*
  • Middle Aged
  • Myocardium / metabolism*
  • Norepinephrine / blood
  • Time Factors

Substances

  • Adrenergic beta-Antagonists
  • Metoprolol
  • Norepinephrine
  • Epinephrine