[Lowering the heart rate in tachycardiac atrial fibrillation by beta receptor blockade].

The effects of the long-acting beta-receptor blocking agent Nadolol on ventricular rate was evaluated by Holter monitoring in 14 patients with chronic atrial fibrillation, in whom no effective control of heart rate could be obtained by digitalis only. There was a significant drop of heart rate after the treatment with 2 times 60 mg Nadolol daily to 70% of control values (ten patients treated for one week). Treatment with 120 mg Nadolol once daily proved to be equally effective in four patients. Reduction of heart rate was most marked in periods of physical activity, while there was only a small effect during periods of rest.