What is the role of digoxin in treating right ventricular (RV) dysfunction?

Digoxin in Right Ventricular Dysfunction

Digoxin has no established role in treating isolated right ventricular dysfunction and should not be used for this indication. The evidence shows no benefit in RV-specific outcomes, and current guidelines do not recommend digoxin for RV dysfunction unless there is concurrent left ventricular systolic dysfunction or atrial fibrillation requiring rate control. 1, 2

Evidence Against Digoxin in Isolated RV Dysfunction

The most recent systematic review (2016) definitively shows digoxin provides no benefit in cor pulmonale and RV failure:

• No statistically significant improvement in right ventricular ejection fraction (RVEF) 2
• No improvement in exercise capacity 2
• No improvement in NYHA functional class or heart failure symptoms 2
• No mortality data available, but no signal of benefit in any measured outcome 2

Older controlled trials confirm these negative findings:

• In 12 patients with chronic airflow obstruction and abnormal RV function, digoxin failed to significantly improve RVEF at rest (44% vs 41%, p=NS) or during exercise (46% vs 44%, p=NS) 3
• Exercise capacity (VO2 max) showed no significant improvement with digoxin 3
• A 1981 trial showed RV ejection fraction improved with digoxin only in patients who also had abnormal left ventricular ejection fraction—suggesting the benefit was from treating concurrent LV dysfunction, not RV dysfunction itself 4

When Digoxin May Be Appropriate in Patients with RV Dysfunction

Digoxin should only be considered if the patient has one of these concurrent conditions:

1. Coexisting Left Ventricular Systolic Dysfunction (LVEF <40%)

• If the patient has biventricular failure with LVEF <40% and persistent symptoms despite ACE inhibitor/ARB, beta-blocker, and diuretic therapy, add digoxin to reduce heart failure hospitalizations 1, 5
• Start with 0.125 mg daily (or every other day) if elderly (>70 years), renal impairment, or low lean body mass 6, 1
• Target serum digoxin concentration: 0.5-0.9 ng/mL 6, 1
• This reduces hospitalizations by 28% (NNT=13 over 3 years) without affecting mortality 1

2. Atrial Fibrillation with Rapid Ventricular Rate

• If the patient has RV dysfunction plus atrial fibrillation with inadequate rate control, use digoxin as an adjunct to beta-blockers for rate control 1, 7
• Beta-blockers remain first-line; add digoxin if resting heart rate remains >80 bpm or exercise heart rate >110-120 bpm despite beta-blocker therapy 1, 7
• Digoxin alone is inadequate for acute rate control (takes 60 minutes to begin working, 6 hours for peak effect) 7

Critical Safety Considerations in RV Dysfunction

Absolute contraindications to digoxin:

• Second- or third-degree heart block without permanent pacemaker 6, 1, 7
• Pre-excitation syndromes (Wolff-Parkinson-White) 1, 7
• Previous digoxin intolerance 1, 7

Mandatory monitoring (especially important in RV dysfunction where renal perfusion may be compromised):

• Serial serum potassium and magnesium—digoxin causes arrhythmias particularly with hypokalemia 1, 7
• Renal function—patients with RV dysfunction often have reduced renal perfusion, increasing digoxin accumulation risk 7
• Target therapeutic level: 0.5-0.9 ng/mL 6, 1

Drug interactions requiring dose reduction by 50%:

• Amiodarone, diltiazem, verapamil, certain antibiotics (clarithromycin, erythromycin), quinidine 1, 7

What to Use Instead for RV Dysfunction

The evidence does not support digoxin for isolated RV dysfunction. Focus on:

• Treating the underlying cause (pulmonary hypertension, chronic lung disease, etc.)
• Diuretics for volume management
• Oxygen therapy if hypoxemic
• Pulmonary vasodilators if pulmonary hypertension is present
• Beta-blockers if concurrent atrial fibrillation requiring rate control 7

Common pitfall: Assuming digoxin will help RV function because it helps LV function—the evidence clearly shows this is not the case. 3, 2, 4