Comparative study of the effect of nifedipine versus diltiazem on exercise performance, serum propranolol levels, and ST-segment abnormalities in patients with chronic stable angina taking propranolol.
Twelve patients (10 men and 2 women), mean age 60.6 years (range 50 to 75), with stable angina pectoris were administered propranolol until beta blockade was evident. Treadmill exercise testing was performed, 24-hour ambulatory electrocardiograms were recorded, and serum propranolol levels were assessed at 1 and 2 hours after dosing with propranolol alone, and after 2 weeks of combined therapy with either nifedipine, 10 or 20 mg, or diltiazem, 60 or 120 mg, administered every 8 hours. Patients were assigned to treatment regimens in randomized, double-blind, crossover fashion. At the time of exercise testing, maximal exercise time, time to angina, peak exercise heart rate and systolic blood pressure and time to 1 mm of ST-segment depression were measured. The rate-pressure product was also calculated. Maximal exercise time increased from 708 +/- 140 seconds with propranolol alone to 795 +/- 156 seconds after combined propranolol-nifedipine therapy (p less than 0.05), and to 790 +/- 107 seconds (p less than 0.05) after propranolol-diltiazem therapy. Time to onset of angina increased from 472 +/- 191 seconds with propranolol alone to 564 +/- 123 seconds (p = NS) after propranolol-nifedipine treatment and to 607 +/- 197 seconds (p less than 0.05) after propranolol-diltiazem treatment. Peak exercise heart rate remained unchanged with propranolol-nifedipine therapy (103 +/- 16 beats/min vs 104 +/- 17 with propranolol alone). However, with propranolol-diltiazem therapy, peak exercise heart rate significantly decreased to 95 +/- 14 beats/min (p less than 0.05); peak systolic blood pressure and rate-pressure products were comparable on all treatment regimens.(ABSTRACT TRUNCATED AT 250 WORDS)
Robinson
K
K
Cardiovascular Unit, Hammersmith Hospital, London, England.
Krikler
S
S
Krikler
D M
DM
D000368:Aged; D000787:Angina Pectoris / Q000188:drug therapy* / Q000503:physiopathology; D002908:Chronic Disease; D004110:Diltiazem / Q000009:adverse effects / Q000627:therapeutic use*; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D004562:Electrocardiography; D015444:Exercise; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D009543:Nifedipine / Q000009:adverse effects / Q000627:therapeutic use*; D011433:Propranolol / Q000097:blood* / Q000627:therapeutic use; D011897:Random Allocation
D011433:Propranolol; D004110:Diltiazem; D009543:Nifedipine