Clinical Observation of Continuous Intravenous Application of Diltiazem in Treatment of Unstable Angina

Objective: To evaluate the effects of diltiazem (Dil) applied continuously and intravenously on unstable angina (UA). Methods: 54 hospitalized UA patients who had failed to respond to nitrates received Dil intravenously. The initial dose was 1 μg /kg·min -1 constantly, and the dose was increased from 1 μg /kg·min -1 to 3 μg /kg·min -1 and then 5 μg /kg·min -1 if angina recurred during treatment. Corresponding doses of oral Dil was prescribed if the angina kept in silence for more than 48 hours under IV infusion of any of those three dosages. Inefficiency was defined as uncontrollable angina attacks at dosage of 5 μg /kg·min -1 . Besides the symptoms, heart rate, blood pressure, ECG and some side effects such as hypotension, arrhythmias, and heart failure were also observed during the trail. Results: After the medication of Dil, the angina attacks were controlled in 45 and 9 patients at dosage of 1 μg /kg·min -1 and 3 μg /kg·min -1 respectively. The total effective rate was 100%. Either the heart rate, blood pressure, or the rate pressure product was significantly decreased with the prolongation of the medication or the increment of dosage, as compared with the baseline value( P 0.05 ). Except two cases who experienced reversible I° AVB, no acute myocardial infarction and no severe side effects were observed during the treatment. Conclusions: The clinical efficacy of Diltiazem therapy is satisfactory in nitrate resistant UA patients.