In Reply: Drs Carbonin and Zuccalà note that the Digitalis Investigation Group (DIG) trial1 only evaluated patients in sinus rhythm. As such, the relevance of our analysis to patients with atrial fibrillation is not known. We support their call for additional research in this area.
Mr de Denus and Dr Spinler suggest that observed differences in glomerular filtration rates are insufficient to explain differences in SDCs between patients with a SDC between 0.5 and 0.8 ng/mL and patients with a SDC of 1.2 ng/mL and higher.3 As we noted, recommended digoxin doses were not only based on renal function but also included patients' age, sex, weight, and other medications.
With regard to a possible digoxin and amiodarone interaction, the DIG trial did not collect data on ventricular arrhythmias or amiodarone use at baseline and thus we can not directly test this hypothesis. However, it seems implausible that a sufficient number . . . [Full Text of this Article]
