XAMOTEROL IMPROVES THE CONTROL OF CHRONIC ATRIAL-FIBRILLATION IN ELDERLY PATIENTS

Twenty digitalized elderly patients with chronic atrial fibrillation w ere randomized into a double-blind crossover study. None was in overt heart failure and all were taking <80 mg frusemide daily. They receive d 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 treatm ent period. Compared with baseline digoxin, xamoterol alone significan tly 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 d igoxin significantly increased nocturnal minimum heart rate (68+/-8, p <0.05) and reduced daytime heart rate (114+/-17, p<0.05). The mean num ber of pauses >1.5 s was significantly reduced by xamoterol alone. Wal king 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 xamoter ol; p<0.02 and 453.7+/-19.2 on xamoterol plus digoxin; p<0.01). No sig nificant 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.