TY - JOUR
T1 - The effect of mibefradil on ischemic episodes with and without increase in heart rate
AU - Tzivoni, Dan
AU - Gilula, Zvi
AU - Klutstein, Marc W.
AU - Reisin, Leonardo
AU - Botvin, Shulamit
AU - Kobrin, Isaac
PY - 2000
Y1 - 2000
N2 - Myocardial ischemia during daily life can be induced by increased demand and by increased coronary tone. The purpose of this study was to assess the mechanism of action of mibefradil, a new T-channel calcium blocker that is a vasodilator with negative chronotropic properties. Included in this study were 114 patients with chronic stable angina pectoris and ischemic episodes during baseline 48-hour ambulatory ECG monitoring (AEM). After a placebo run-in period patients received 50 mg, 100 mg, or 150 mg of mibefradil per day and repeat 48 hours AEM was performed. Ischemic episodes were divided into 2 categories: Type I is those in which an increase in heart rate >10% preceded the development of 1 mm ST depression; Type II is those with ≤10% increase in heart rate. Of the 625 ischemic episodes recorded at baseline, 83% were Type I and 17% were Type II. At 50 mg mibefradil dose, there was a significant decrease in the number of Type I ischemic episodes but not of Type II. At doses of 100 mg and 150 mg/day, there was a significant decrease in frequency of both types of ischemic episodes. At a low dose of 50 mg/day, mibefradil reduces ischemia predominantly preventing an increase in heart rate, while at higher doses of 100 mg and 150 mg/day, it also acted as a vasodilator suppressing episodes associated with increased coronary tone.
AB - Myocardial ischemia during daily life can be induced by increased demand and by increased coronary tone. The purpose of this study was to assess the mechanism of action of mibefradil, a new T-channel calcium blocker that is a vasodilator with negative chronotropic properties. Included in this study were 114 patients with chronic stable angina pectoris and ischemic episodes during baseline 48-hour ambulatory ECG monitoring (AEM). After a placebo run-in period patients received 50 mg, 100 mg, or 150 mg of mibefradil per day and repeat 48 hours AEM was performed. Ischemic episodes were divided into 2 categories: Type I is those in which an increase in heart rate >10% preceded the development of 1 mm ST depression; Type II is those with ≤10% increase in heart rate. Of the 625 ischemic episodes recorded at baseline, 83% were Type I and 17% were Type II. At 50 mg mibefradil dose, there was a significant decrease in the number of Type I ischemic episodes but not of Type II. At doses of 100 mg and 150 mg/day, there was a significant decrease in frequency of both types of ischemic episodes. At a low dose of 50 mg/day, mibefradil reduces ischemia predominantly preventing an increase in heart rate, while at higher doses of 100 mg and 150 mg/day, it also acted as a vasodilator suppressing episodes associated with increased coronary tone.
KW - Ambulatory ECG monitoring
KW - Coronary tone
KW - Mibefradil
KW - Myocardial ischemia
KW - Silent ischemia
KW - T-channel calcium antagonist
UR - http://www.scopus.com/inward/record.url?scp=0033786082&partnerID=8YFLogxK
U2 - 10.1023/A:1007889006370
DO - 10.1023/A:1007889006370
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C2 - 11101198
AN - SCOPUS:0033786082
SN - 0920-3206
VL - 14
SP - 503
EP - 509
JO - Cardiovascular Drugs and Therapy
JF - Cardiovascular Drugs and Therapy
IS - 5
ER -