Should digoxin be continued or initiated in patients with heart failure with reduced ejection fraction (HFrEF) undergoing coronary angiography (CAG)?

Digoxin Management Before Coronary Angiography in HFrEF

If a patient with HFrEF is already taking digoxin, continue it through coronary angiography without interruption; if not currently on digoxin, do not initiate it specifically for the procedure. 1

Rationale for Continuation

Digoxin withdrawal in patients already established on therapy can precipitate clinical worsening of heart failure. 1 The 2022 AHA/ACC/HFSA guidelines explicitly state that "clinical worsening after withdrawal of digoxin has been shown," making discontinuation before CAG potentially harmful. 1

• Digoxin has no significant hemodynamic effects that would complicate coronary angiography procedures 2
• The drug does not cause hypotension, which is actually advantageous in the periprocedural setting 3
• Digoxin's pharmacokinetic profile (half-life 1.5-2.0 days in normal renal function) means acute discontinuation provides no immediate benefit while risking decompensation 2

Rationale Against New Initiation

Do not start digoxin specifically before CAG because it provides no mortality benefit and its primary indication is for symptomatic patients who remain refractory despite optimized guideline-directed medical therapy (GDMT). 1

• The 2022 AHA/ACC/HFSA guidelines assign digoxin only a Class 2b recommendation (Level B-R evidence), meaning it "might be considered" only after GDMT optimization 1
• The landmark DIG trial showed digoxin reduces heart failure hospitalizations by 28% but has no effect on mortality 1
• Modern evidence suggests digoxin's benefit is uncertain in patients already on contemporary GDMT (beta-blockers, ACE inhibitors/ARBs, mineralocorticoid receptor antagonists, SGLT2 inhibitors) 1

Critical Periprocedural Considerations

Renal Function Monitoring

Contrast-induced nephropathy from CAG can significantly alter digoxin clearance and increase toxicity risk. 2

• Digoxin is 50-70% renally excreted unchanged, making it highly dependent on glomerular filtration rate 2
• Post-CAG renal function should be checked within 48-72 hours in patients on digoxin 2
• If creatinine clearance decreases significantly post-procedure, reduce digoxin dose accordingly: for CrCl 10-50 mL/min, use 0.125 mg daily; for CrCl <10 mL/min, use 0.0625 mg daily or every other day 3, 2

Electrolyte Management

Hypokalemia and hypomagnesemia dramatically increase digoxin toxicity risk, and both can occur with contrast-induced diuresis or pre-procedural NPO status. 1, 3

• Check potassium and magnesium levels before CAG in all patients on digoxin 1, 3
• Maintain potassium >4.0 mEq/L and magnesium >2.0 mg/dL throughout the periprocedural period 3
• Serial electrolyte monitoring is mandatory, particularly if loop diuretics are being used 1

Arrhythmia Risk

Digoxin can cause both atrial and ventricular arrhythmias, particularly in the context of ischemia during or after CAG. 1

• Continuous telemetry monitoring is advisable for 24 hours post-CAG in patients on digoxin 1
• Be vigilant for signs of digoxin toxicity: new arrhythmias, gastrointestinal symptoms (nausea, vomiting), visual disturbances, or confusion 3, 2

Dosing Considerations if Continuing Therapy

For patients already on digoxin undergoing CAG, verify the dose is appropriate for their renal function and maintain target serum concentrations of 0.5-0.9 ng/mL. 1, 3

• Standard maintenance dosing: 0.125-0.25 mg daily for patients <70 years with normal renal function 1, 2
• Reduced dosing: 0.125 mg daily or every other day for patients >70 years, impaired renal function, or low lean body mass 1, 3
• Serum digoxin levels ≥1.2 ng/mL are associated with significantly higher mortality risk 1

Drug Interactions to Consider

Several medications commonly used in the cardiac catheterization setting can increase digoxin levels. 3

• Amiodarone (reduce digoxin dose by 30-50%) 3
• Verapamil (reduce digoxin dose and monitor levels closely) 3
• Clarithromycin or erythromycin if used for prophylaxis (monitor levels) 3

Special Population: Atrial Fibrillation with HFrEF

In patients with both HFrEF and atrial fibrillation, digoxin continuation is particularly important for rate control during the periprocedural period. 1, 4

• Digoxin provides rate control without lowering blood pressure, which is advantageous when beta-blockers may need to be held 1, 3
• Recent evidence shows digoxin in HFrEF patients with atrial fibrillation reduces heart failure readmissions without increasing mortality 4
• ESC guidelines give Class I recommendation (Level C evidence) for digoxin use in AF with LVEF <40% for rate control 1

Post-Procedure Management

Resume or adjust digoxin dosing based on post-CAG renal function and clinical status. 2

• Reassess volume status and adjust diuretics before modifying digoxin dose 1
• If significant renal impairment develops (CrCl decrease >25%), reduce digoxin dose or extend dosing interval 2
• Consider checking a digoxin level 5-7 days post-CAG if renal function changed or if clinical signs of toxicity emerge 2