Metabolic and hemodynamic effects of nicardipine during pacing-induced angina pectoris.
During repeat exercise testing in 10 patients with stable angina, individual optimal doses of nicardipine were determined. Hemodynamic values and cardiac metabolism were studied during 2 pacing periods carried out before and after this dose (mean 5.3 mg). Postpacing ST-segment depression diminished (1 mm) after nicardipine administration (p less than 0.05), whereas pacing time to onset of angina did not change. Nicardipine administration increased heart rate 16% (p less than 0.005) and reduced systolic (10%) and diastolic (8%) blood pressures (both p less than 0.005). Coronary blood flow increased 16% (p less than 0.05) and coronary vascular resistance decreased 24% (p less than 0.01). Myocardial oxygen consumption was unchanged despite an 11% decrease in rate-pressure product during pacing (p less than 0.02). In the control state before nicardipine administration, metabolic signs of ischemia included release of lactate across the heart in 7 patients, decreased mean free fatty acid and glutamate uptake and alanine release during pacing, together with increased glucose uptake and citrate release during recovery. After nicardipine lactate release decreased in 5 of the 7 patients, pacing no longer changed free fatty acid, glutamate and alanine uptake/release from the level at rest. During recovery glucose uptake was reduced and citrate release was unaffected. The hemodynamic data indicate that nicardipine is a systemic and coronary vasodilator, increasing oxygen supply to the ischemic myocardium. The metabolic results indicate a change in substrate utilization toward that of normal heart, suggesting improved aerobic energy supply.
D000409:Alanine / Q000378:metabolism; D000787:Angina Pectoris / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology*; D001794:Blood Pressure / Q000187:drug effects; D006328:Cardiac Catheterization; D002304:Cardiac Pacing, Artificial; D002951:Citrates / Q000378:metabolism; D003326:Coronary Circulation / Q000187:drug effects; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism; D005971:Glutamates / Q000378:metabolism; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007773:Lactates / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D009529:Nicardipine / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
D002951:Citrates; D005230:Fatty Acids, Nonesterified; D005971:Glutamates; D007773:Lactates; D009529:Nicardipine; D005947:Glucose; D000409:Alanine