Digitalis - a dangerous drug in atrial fibrillation? An analysis of the SPORTIF III and V data

Knut Gjesdal ^1*, Jan Feyzi ² and S Bertil Olsson ³

¹ Ulleval University Hospital, Norway
² University of Wisconsin, United States
³ University of Lund, Sweden

^* To whom correspondence should be addressed. E-mail: knut.gjesdal{at}medisin.uio.no.

Accepted 16 January 2007

Abstract

Objective In heart failure, digitalis increases exercise capacity and reduces morbidity, but has no effect on survival. This raises the suspicion that the inotropic benefits of digitalis could be counteracted by serious adverse effects. Patients with atrial fibrillation (AF) were studied to clarify this.

Design In the Stroke Prevention using an ORal Thrombin Inhibitor in atrial Fibrillation (SPORTIF) III and V studies, 7329 moderate-to-high risk AF patients were randomized to preventive treatment of thromboembolism, either with warfarin or the oral direct thrombin inhibitor ximelagatran. The present study investigated the survival of users and non-users of digitalis.

Results At baseline, 53.4% of the study population used digitalis, and these patients had a higher mortality than non-users (6.5% vs. 4.1%, P<0.0001; hazard ratio: 1.58 [95% CI: 1.29-1.94]). Digitalis users also had more baseline risk factors. After multivariate risk factor adjustment, the increased mortality persisted (P=0.0002; hazard ratio: 1.53 [95% CI: 1.22-1.92 vs. 1.23-1.92]).

Conclusions The results suggest that digitalis, like other inotropic drugs, may increase mortality. This may be concealed in heart failure, but be revealed in AF patients, who need the rate-reducing effect of digitalis, but do not benefit much from an increased inotropy. Cautious interpretation of the data is mandatory since the patients were not randomized with respect to digitalis use.

Keywords: atrial fibrillation, digitalis, mortality, thromboembolism

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• Testa, L, Bhindi, R, Banning, A P (2008). Digitalis: a dangerous drug in atrial fibrillation?. Heart 94: 1654-1654 [Full Text]  
• Gjesdal, K, Feyzi, J, Olsson, S B (2008). The authors' reply:. Heart 94: 1654-1655 [Full Text]  
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