Efficacy of amlodipine besilate therapy for variant angina: evaluation by 24-hour Holter monitoring.

The efficacy of amlodipine, a calcium antagonist, was investigated in 12 patients with variant angina. Amlodipine was administered at a dose of 5 mg once daily, and efficacy was assessed from the frequency of anginal attacks, the frequency of ST elevation or depression, and the extent of ST segment changes [ST segment elevation or depression (mm) x duration (seconds)] on the Holter ECG before and after treatment. The frequency of ST elevation during the observation period was 1.67 +/- 0.33 times/day (symptomatic attacks: 1.17 +/- 0.21/day; asymptomatic attacks: 0.50 +/- 0.19/day), and this significantly decreased to zero per day (both symptomatic and asymptomatic attacks) after treatment (p < 0.05). The extent of ST segment elevation during the observation period was 507.5 +/- 156.6 mm.sec/day (symptomatic: 382.5 +/- 102.9 mm.sec/day; asymptomatic: 125.0 +/- 62.0 mm.sec/day), and such changes were completely suppressed (both symptomatic and asymptomatic) by treatment (p < 0.05). The frequency of ST depression was 2.08 +/- 0.42 times/day (symptomatic: 0.25 +/- 0.13/day; asymptomatic: 1.83 +/- 0.37/day) during the observation period, while it was 1.50 +/- 0.36 times/day (symptomatic: 0.25 +/- 0.13/day; asymptomatic: 1.25 +/- 0.30/day) after treatment. Although anginal attacks remained unchanged, asymptomatic attacks tended to decrease (p = 0.07).(ABSTRACT TRUNCATED AT 250 WORDS)