Xamoterol improves the control of chronic atrial fibrillation in elderly patients

Twenty digitalized elderly patients with chronic atrial fibrillation were randomized into a double-blind cross-over study. None was in overt heart failure and all were taking < 80 mg frusemide daily. They received xamoterol 200 mg b.d. for 2 months with their usual dose of digoxin for 1 month and placebo digoxin for the other month. Twenty-four-hour heart rate analysis was done at baseline and at the end of each treatment period. Compared with baseline digoxin, xamoterol alone significantly increased nocturnal minimum heart rate [85 +/- 17 vs. 62 +/- 9 (mean +/- SD), p < 0.0001] without affecting daytime maximum heart rate (132 +/- 18 vs. 122 +/- 20, p = NS). Compared with baseline digoxin, xamoterol plus digoxin significantly increased nocturnal minimum heart rate (68 +/- 8, p < 0.05) and reduced daytime heart rate (114 +/- 17, p < 0.05). The mean number of pauses > 1.5 s was significantly reduced by xamoterol alone. Walking distance in 6 minutes was 406.1 +/- 27.1 m (mean +/- SE) at baseline and improved significantly on both treatments (450.3 +/- 19.8 on xamoterol; p < 0.02 and 453.7 +/- 19.2 on xamoterol plus digoxin; p < 0.01). No significant change was found in subjective measurements of palpitations, breathlessness and well-being using visual analogue scales. Xamoterol combined with digoxin improves effort tolerance and heart-rate control by reducing diurnal tachycardia and nocturnal bradycardia and pauses.