Efficacy and safety of intravenous nadolol for supraventricular tachycardia.

In a double-blind, placebo-controlled, parallel trial of intravenous nadolol in the treatment of sustained supraventricular tachycardia (SVT), 29 patients (20 men, 9 women) were studied. Mean age was 55 years and all patients were required to have well-documented SVT with a ventricular rate greater than or equal to 120/min that was sustained for at least 30 minutes. Patients received sequential doses of 0.01, 0.02 and 0.04 mg/kg of nadolol or placebo at 10 minute intervals. The maximum total dosage of nadolol was 10 mg. Measurements taken during 10 minute monitoring periods after each administration included heart rate, ventricular rate and systolic and diastolic blood pressures. A positive response was defined as a greater than or equal to 20% decrease in heart rate, heart rate less than or equal to 100 beats/min or conversion to normal sinus rhythm. Eleven (79%) of patients given nadolol and 3 (20%) of placebo-treated patients demonstrated a positive response. Of the 11 responders to nadolol, 9 patients responded after the first dose, one after the second dose and one after the third dose. Significant (p less than 0.001) mean reductions in heart rate and ventricular rate were observed with nadolol, but not with placebo. Five (36%) of the patients given nadolol and only 2 (14%) of the patients who received placebo were converted to normal sinus rhythm. Adverse effects were limited to 1 episode of asymptomatic hypotension and 1 episode of wheezing with nadolol and 1 episode of asymptomatic hypotension with placebo. Nadolol is effective in controlling ventricular response in patients with sustained SVT.(ABSTRACT TRUNCATED AT 250 WORDS)