Anti-arrhythmic properties of the alpha-adrenoceptor blocking drug indoramin

1. The anti-arrhythmic properties of the alpha-adrenoceptor blocking drug indoramin were compared with the effect of disopyramide and placebo in a randomised, single-blind, cross-over study. Two doses of indoramin were tested, 25 mg and 50 mg and the dose of disopyramide was 150 mg. All treatments were administered three times daily. 2. Forty patients with benign ventricular arrhythmia were studied. 3. Assessment was by 24 h ambulatory electrocardiography at entry and at the end of each 2 week treatment period. 4. Indoramin was found to have a significant anti-arrhythmic effect compared with placebo, but only at the higher dose tested. 5. The anti-arrhythmic effect was less than that achieved with disopyramide. 6. The mechanism for this anti-arrhythmic effect is unknown but these results suggest that alpha-adrenoceptor blockade may merit further attention as an anti-arrhythmic treatment.