A comparison of digoxin, diltiazem and their combination in the treatment of atrial fibrillation

Fourteen patients (four females) with chronic atrial fibrillationwere entered into a randomized, double-blind crossover studyto compare the effects of treatment with diltiazem alone, digoxinalone, and a combination of diltiazem plus digoxin. The doseof digoxin was adjusted so as to achieve serum concentrationswithin the range 1.3–2.6 nmoll^–1 between six andeight hours after dosing. Four patients were withdrawn fromthe study; three patients experienced side effects while takingdiltiazem and one reverted to sinus rhythm while taking digoxin.Among the remaining 10 patients, mean heart rates were significantlylower during treatment with the combination of digoxin and diltiazemthan with digoxin alone both at rest, after exercise and duringambulatory ECG monitoring. Post-exercise heart rates were reducedby 15% with combination therapy when compared with digoxin alone(151.9 vs. 128.1 bpm), but there was no evidence that this reductionin ventricular rate was associated with improved exercise tolerance.The results suggest that further reduction of the rapid ventricularrates seen in digitalized patients with AF by the use of diltiazemdoes not appear to be of benefit in the majority of patients.