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A 65-year-old man complained of progressive dyspnoea on exertion for a period of 14 weeks with recent history of orthopnoea. He also gave a history of significant loss of weight (6.5 kg in seven months). On physical examination his heart rate was 120 beats/min and blood pressure was 110/80 mmHg. Jugular venous pressure was raised and pedal oedema was present. Cardiac impulse was just outside the midclavicular line in the 6th intercostal space. Cardiac auscultation revealed first and second heart sounds of normal intensity. Audible S3 gallop was present. Auscultation of the lungs revealed fine bibasilar crepts. Electrocardiogram showed normal sinus rhythm and T wave inversion in leads Vi to V6.

Digoxin is used in clinical practice for two major purposes: To improve ventricular performance in heart failure with reduced ejection fraction and to control the ventricular rate in atrial fibrillation. It is a cardiac glycoside with a positive inotropic effect and causes atrioventricular nodal inhibition through vagomimetic effect. It also decreases the sympathetic drive generated by the failing circulation, which provides a rational in using the drug in congestive heart failure (CHF) with sinus rhythm. The use of this drug is a standard therapy in the treatment of CHF with atrial fibrillation. However, the dose adjustment of this drug is difficult because of the variation in its pharmacokinetic characteristics, the variability in its clearance, and the lack of a good relationship between the dose and the desired effect and its narrow therapeutic range. This creates difficulty for clinicians to choose the appropriate dosage of the drug to get the desired benefit without the risk of toxicity. In many countries, serum concentration monitoring is not always possible, so it is common in clinical practice to drop the medication for 1 or 2 days a week, giving the drug a ‘holiday,’ to avoid the risk of toxicity. This is contrary to the use of this drug without interruption in countries where routine serum concentration monitoring is possible. This review provides a summary of the evidence relating to the rationale behind using digoxin holiday and the therapeutic implications of digoxin holiday. Much of the information is available from prospective crossover clinical trials. There are no randomised control trials of digoxin holiday in patients with heart failure and/or atrial fibrillation.

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