The effects of phentolamine and nitroglycerin on right-sided hemodynamics in cardiac patients can be explained by a shift of the systemic venous return curve and right-ventricular output curve

Jpn Circ J. 1992 Aug;56(8):801-14. doi: 10.1253/jcj.56.801.

Abstract

The present study investigated the effects of phentolamine (PH) and nitroglycerin (NG) on the hemodynamics of the right heart in patients with cardiac disease. The patients were divided into a well-functioning left heart group (W group, n = 15) and a poorly-functioning left heart group (P group, n = 15). Right cardiac hemodynamic parameters and plasma noradrenaline (NA) and adrenaline (A) concentrations were measured before and after administering PH (0.1 mg/kg, i.v.) or NG (0.6 mg, sublingual). In a parallel animal study we obtained a systemic venous return curve by measuring mean circulatory pressure (MCP), mean right atrial pressure (RAP) and cardiac output, before and after administering PH (0.1 mg/kg, i.v.) or NG (12.5 micrograms/kg, i.v.) to anesthetized open-chest dogs (n = 14). We used MCP data (W group: 7.5 mmHg, P group: 10 mmHg) obtained in a separate series of human studies in our laboratory. We constructed the venous return curve by connecting the MCP point on abscissa with the cardiac index (CI)-RAP plot obtained in the clinical study. We also constructed the right ventricular output curve by connecting the point of -2 mmHg on the abscissa with the CI-RAP plot. We obtained the following results: (1) PH shifted the CI-RAP plot to the left and upwards, while NG shifted the CI-RAP plot to the left almost horizontally on the CI-RAP plane, where CI was plotted on ordinate and RAP on abscissa. The length [formula: see text] C = control point, PH = point after PH) of the shift of CI-RAP plot due to PH was greater in the P group than in W group, while there was no difference in the length [formula: see text] C = control point, NG = point after NG) of the shift of CI-RAP plot due to NG between P and W groups. (2) Both PH and NG significantly elevated plasma NA and A concentrations in both the W and P groups. In the P group, PH increased the plasma NA concentration significantly more than did NG, but both drugs increased plasma A concentration to a similar extent. (3) Both PH and NG significantly decreased the mean pulmonary arterial pressure with NG doing so significantly more than PH.(ABSTRACT TRUNCATED AT 400 WORDS)

Publication types

  • Comparative Study

MeSH terms

  • Adrenergic alpha-Antagonists / pharmacology
  • Animals
  • Cardiac Output / drug effects*
  • Dogs
  • Epinephrine / blood
  • Heart Failure / drug therapy*
  • Heart Failure / physiopathology
  • Hemodynamics / drug effects
  • Humans
  • Nitroglycerin / pharmacology*
  • Norepinephrine / blood
  • Phentolamine / pharmacology*
  • Receptors, Adrenergic, beta / drug effects
  • Ventricular Function, Right / drug effects*

Substances

  • Adrenergic alpha-Antagonists
  • Receptors, Adrenergic, beta
  • Nitroglycerin
  • Norepinephrine
  • Epinephrine
  • Phentolamine