Effect of propranolol on indices of intermittent myocardial ischemia, assessed by exercise testing and ambulatory ST-segment monitoring.

Seventy three patients (63 males and 10 females) aged 41-75 years with established stable exertional angina pectoris were studied in a double-blind fashion to confirm the efficacy of 80 mg propranolol administered three times daily and also to examine its effect on ST-segment changes in the electrocardiogram by ambulatory ST-segment monitoring and exercise testing using on-line computer analysis. During ambulatory monitoring, episodes of ST-segment depression in lead CM5 were significantly reduced from 6.5 +/- 0.7 during placebo to 3.4 +/- 0.6 during propranolol therapy (p less than 0.001). The total duration of ST-segment depression was also significantly reduced and the maximal depth of ST-segment depression improved from 2.6 +/- 0.2 mm during placebo to 1.7 +/- 0.2 mm during propranolol therapy (p less than 0.001). The mean +/- SEM exercise time of 5.5 +/- 0.2 minutes on placebo increased to 8.6 +/- 0.4 minutes on propranolol 240 mg daily (p less than 0.001). The 1 mm ST-segment depression time of 3.5 +/- 0.2 minutes on placebo in lead CM5 was prolonged to 6.2 +/- 0.3 minutes during propranolol therapy (p less than 0.001). Propranolol treatment significantly reduced the resting and maximal heart rates (p less than 0.001). The maximal ST-segment depression during exercise in lead CM5 was reduced from 2.3 +/- 0.1 mm on placebo to 1.9 +/- 0.1 mm with propranolol (p less than 0.01). Similarly, the rate-pressure product at peak exercise of 188 +/- 5 units on placebo was reduced to 144 +/- 3 units with propranolol (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

RCT Entities:   Population Interventions Outcomes