Changes in coronary haemodynamics and myocardial metabolism at rest and during exercise after a cardiotonic drug (prenalterol) in patients with coronary artery disease.
To elucidate the myocardial metabolic and haemodynamic effects of an inotropic drug in patients with coronary artery disease (CAD) without evident congestive heart failure (CHF), the acute effects of prenalterol were studied in nine patients. Patients with documented CAD by leftsided cardioangiography and end-diastolic pressure greater than 15 mm Hg were included in the study. They were examined at rest and during supine exercise at a level just below their anginal threshold before and after prenalterol. At rest, rate pressure product (RPP) increased by 40% (P less than 0.01), cardiac index rose 20% (P less than 0.01), cardiac venous flow (CVF) increased by 18% (P less than 0.05), and myocardial oxygen consumption (MVO2) increased by 20% (P less than 0.05) after prenalterol administration. Despite a decrease in mean pulmonary capillary venous pressure (PCV) of 40% (P less than 0.01), myocardial lactate extraction fell significantly (P less than 0.01) and lactate production was observed in three of nine patients compared to before prenalterol administration. During exercise, RPP increased by 20% (P less than 0.01), cardiac index remained unchanged, CVF increased by 25% (NS) and MVO2 showed a tendency to an increase (NS) after prenalterol administration. Mean PCV pressure decreased by 30% (P less than 0.01). Myocardial lactate extraction was markedly reduced during exercise (P less than 0.01) and five of nine patients showed lactate production compared to that before prenalterol administration. Thus, despite a decrease in left ventricular filling pressure, increased myocardial oxygen demand occurred after acute administration of prenalterol. Prenalterol and probably similar inotropic drugs should be used cautiously in patients with CAD without clinical evidence of congestive heart failure.
Westheim
A
A
Laboratory of Clinical Physiology, Ullevaal Hospital, University of Oslo, Norway.
Bae
E
E
Christensen
C C
CC
Fønstelien
E
E
Grendahl
H
H
Muller
O
O
D002407:Catheterization, Swan-Ganz; D003327:Coronary Disease / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology*; D015444:Exercise; D006321:Heart / Q000503:physiopathology*; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007275:Injections, Intravenous; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D011294:Prenalterol / Q000008:administration & dosage / Q000494:pharmacology*
D007773:Lactates; D019344:Lactic Acid; D011294:Prenalterol