Can stopping digoxin unmask previously compensated heart failure even if the patient does not deteriorate immediately?

Stopping digoxin while keeping metoprolol can unmask the heart failure digoxin was controlling, and the beta-blocker may hide the warning signs.

The PROVED and RADIANCE trials showed that withdrawing digoxin from stable heart failure patients on background therapy (diuretics and ACE inhibitors) led to significantly more decompensation [2]. Those patients were stable enough to be randomized. The 2015 study in the evidence here confirms the pattern: when digoxin was withdrawn from stable patients on optimal therapy, BNP levels rose from 405 to 604 ng/L (p=0.02) and six-minute walk distance dropped from 474 to 455 meters (p=0.02) [1]. Those are objective measures of worsening heart failure, not just symptoms.

Now add metoprolol. Beta-blockers lower heart rate and reduce contractility. In heart failure, they save lives long-term but can initially worsen symptoms because the heart depends on sympathetic drive. If digoxin was providing the inotropic support that kept the patient compensated, removing it while the beta-blocker continues means the heart loses one support while the other actively restrains it. The patient may not develop a racing pulse or palpitations as a warning sign, because metoprolol suppresses those. Instead, the first sign could be fatigue, fluid retention, or sudden decompensation.

The 2000 study on carvedilol and digoxin together found that the group on both drugs had a 33.3% hospitalization rate, while the group on carvedilol alone had 22.7% [3]. That does not prove digoxin withdrawal causes harm when beta-blockers continue, but it shows the combination is not simply additive. The carvedilol-alone group did better, which raises the question of whether digoxin adds anything once a beta-blocker is on board. But that was a different question: patients who stayed on both, not patients who had digoxin withdrawn.

The 2016 study on beta-blockers and digoxin together found that patients discharged on both had lower 1-year mortality (31%) than those on digoxin alone (44%) [2]. That confirms the combination works. It does not tell us what happens when you remove digoxin from that combination.

My call: stopping digoxin while continuing metoprolol in a patient whose heart failure was previously unrecognized and controlled by digoxin carries a real risk of decompensation, and the beta-blocker may mask the early warning signs. The safer path is to get a baseline ECG and digoxin level, then consider a slow taper under monitoring, not an abrupt stop. Confidence: moderate, because the evidence on this exact combination (digoxin withdrawal with concurrent beta-blocker) is not directly tested in the retrieved studies, but the withdrawal trial data and the mechanism point in the same direction.