Acute effects of nifedipine versus isosorbide dinitrate on exercise tolerance in patients with isolated coronary artery occlusion and collaterals.
The acute effects of slow-release nifedipine and isosorbide dinitrate on exercise tolerance were compared in nine patients with isolated total coronary artery occlusion showing retrograde filling via collaterals. All patients had a reproducible positive exercise stress test off medication before the study. Each patient was randomized to 10 mg slow-release nifedipine and 5 mg isosorbide dinitrate in a single-blind, cross-over study. The exercise stress test was performed 30 minutes after drug administration. After nifedipine, three patients had a negative exercise stress test, whereas the test was negative after isosorbide dinitrate only in one patient. A significantly higher exercise tolerance was detected at peak exercise after nifedipine than after isosorbide dinitrate, as shown by a longer exercise time (380 +/- 44 vs. 295 +/- 41 seconds, p less than 0.001), a more increased maximum work load (355 +/- 89 vs. 255 +/- 55 W x min, p less than 0.02), and a higher rate-pressure product (30,300 +/- 2,500 vs. 26,100 +/- 2,700, p less than 0.01). In conclusion, these results seem to suggest that nifedipine may have a vasomotor effect on collaterals, since it elevated the threshold of ischemia more than isosorbide dinitrate did in patients with isolated coronary artery occlusion, showing retrograde filling via collaterals.
Barillà
F
F
Department of Cardiology, University of Rome, La Sapienza, Italy.
Pelliccia
F
F
Valente
A
A
Cianfrocca
C
C
Romeo
F
F
Reale
A
A
D000787:Angina Pectoris / Q000188:drug therapy; D000792:Angiography; D001157:Arterial Occlusive Diseases / Q000188:drug therapy*; D003097:Collateral Circulation / Q000187:drug effects / Q000502:physiology*; D003327:Coronary Disease / Q000188:drug therapy*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006801:Humans; D007548:Isosorbide Dinitrate / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009543:Nifedipine / Q000494:pharmacology* / Q000627:therapeutic use; D015203:Reproducibility of Results
D009543:Nifedipine; D007548:Isosorbide Dinitrate