HEART RHYTHM DISORDERS AND PACEMAKERS

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

K Gjesdal¹, J Feyzi², S B Olsson³

¹ Ullevål University Hospital, University of Oslo, Norway
² Statistical Data Analysis Center, Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison, WI, USA
³ Department of Cardiology, University of Lund, Sweden

Professor K Gjesdal, Ullevål University Hospital, 0407 Oslo, Norway; knut.gjesdal{at}medisin.uio.no

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 may 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 patients with AF at moderate-to-high risk were randomised to preventive treatment of thromboembolism, either with warfarin or the oral direct thrombin inhibitor ximelagatran. The survival of users and non-users of digitalis was investigated.

Results: At baseline, 53.4% of the study population used digitalis, and these patients had a higher mortality than non-users (255/3911 (6.5%) vs 141/3418 (4.1%), p<0.001; hazard ratio (HR) = 1.58 (95% CI 1.29 to 1.94)). Digitalis users also had more baseline risk factors. After multivariate risk factor adjustment, the increased mortality persisted (p<0.001; HR = 1.53 (95% CI 1.22 to 1.92 vs 1.23 to 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 patients with AF, 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 randomised with respect to digitalis use.

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This article has been cited by other articles:

• 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]  
• Simpson, R. J Jr (2008). Assessing the safety of drugs through observational research. Heart 94: 129-130 [Full Text]  

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