From the Guidelines
Digoxin is recommended as a first-choice drug, along with beta-blockers, to control heart rate and reduce symptoms in patients with atrial fibrillation (AF) and left ventricular ejection fraction (LVEF) ≤40%. According to the most recent guidelines, specifically the 2024 ESC Guidelines for the management of atrial fibrillation 1, digoxin plays a crucial role in managing AF, particularly in patients with reduced LVEF.
The mechanism by which digoxin helps control heart rate in AF involves slowing electrical conduction through the atrioventricular (AV) node, thereby reducing the number of atrial impulses that reach the ventricles. Typically, digoxin is prescribed at a dose of 0.125-0.25 mg daily for adults. It works by inhibiting the sodium-potassium ATPase pump in cardiac cells, which increases intracellular calcium and strengthens heart contractions while simultaneously slowing heart rate.
Key points to consider when using digoxin for AF management include:
- Monitoring blood levels, especially in elderly patients or those with kidney dysfunction, due to its narrow therapeutic window (target: 0.5-0.9 ng/mL) 1.
- The full rate-controlling effect may take several days to develop.
- Patients should be monitored for signs of toxicity, including nausea, visual disturbances, confusion, and cardiac arrhythmias.
- Digoxin is less effective during high sympathetic states like exercise or acute illness and does not reduce mortality in atrial fibrillation patients like some other rate-control medications.
In clinical practice, the choice between rate control and rhythm control strategies for AF management depends on various factors, including symptoms, left ventricular function, and the presence of heart failure. Beta-blockers and digoxin are recommended for patients with AF and LVEF ≤40%, highlighting the importance of digoxin in this specific patient population 1.
From the FDA Drug Label
Digoxin is indicated for the control of ventricular response rate in patients with chronic atrial fibrillation. Peak digoxin body stores larger than the 8 to 12 mcg/kg required for most patients with heart failure and normal sinus rhythm have been used for control of ventricular rate in patients with atrial fibrillation Doses of digoxin used for the treatment of chronic atrial fibrillation should be titrated to the minimum dose that achieves the desired ventricular rate control without causing undesirable side effects.
Digoxin helps control heart rate in patients with atrial fibrillation (afib) by slowing the ventricular response rate. The dose of digoxin used for this purpose should be titrated to the minimum dose that achieves the desired ventricular rate control without causing undesirable side effects.
- The goal is to achieve a reduction in ventricular rate with minimal risk of toxicity.
- No specific target rate is established, and the dosage should be individualized based on clinical assessment. 2 2 2
From the Research
Mechanism of Action
- Digoxin helps control heart rate in patients with atrial fibrillation (afib) by increasing the strength of cardiac contractions and slowing the heart rate [ 3 ].
- It works by inhibiting the sodium-potassium ATPase pump, which leads to an increase in intracellular calcium and a subsequent increase in contractility [ 4 ].
Efficacy in Controlling Heart Rate
- Digoxin is effective in controlling heart rate at rest, but its effectiveness during exercise is limited [ 3 ].
- The combination of digoxin with a beta-blocker or a non-dihydropyridine calcium channel antagonist can control heart rate both at rest and during exercise [ 3 ].
- Digoxin may be useful in patients with afib and heart failure, particularly in those with hypotension or an absolute contraindication to beta-blocker treatment [ 5 ].
Safety Profile
- Digoxin is generally considered safe in patients with afib, with few reported side effects requiring drug withdrawal [ 3 ].
- However, the safety profile of digoxin in patients with heart failure has not been directly addressed due to the exclusion of these patients in most studies [ 3 ].
- Recent studies have correlated therapeutic use of digoxin with increased mortality, but these findings are not conclusive due to potential biases [ 6 ].
Combination Therapy
- The combination of digoxin with other agents, such as beta-blockers or non-dihydropyridine calcium channel blockers, can enhance its effectiveness in controlling heart rate [ 5 ].
- The addition of diltiazem to digoxin therapy has been shown to result in better control of heart rate at rest and during exercise [ 7 ].