Efficacy of amoldipine besilate therapy for variant angina: Evaluation by 24-hour Holter monitoring

Summary 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) × 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). The extent of ST depression during the observation period was 632.5±239.4 mm·sec/day (symptomatic: 105.0±64.4 mm·sec/day; asymptomatic: 527.5±189.5 mm·sec/day), and this significantly decreased to 333.8±111.4 mm·sec/day (symptomatic: 50.0±31.2 mm·sec/day; asymptomatic: 283.8±102.6 mm·sec/day) after treatment (p<0.05). The frequency of anginal attacks during the observation period was 1.27±0.18 times/day, and this significantly decreased to 0.40±0.12/day after 1 week of treatment and to 0.22±0.07/day after 2 weeks of treatment (p<0.05). These results suggest that amlodipine is effective for treating variant angina at a daily dose of 5 mg.