What can be given for atrial fibrillation (AFib) with rapid ventricular response (RVR) and rhabdomyolysis with tachycardia?

From the Guidelines

For atrial fibrillation with rapid ventricular response (AFib with RVR) complicated by rhabdomyolysis, the primary treatment should focus on rate control medications, with calcium channel blockers such as diltiazem being a preferred option due to the potential of beta-blockers to worsen hyperkalemia associated with rhabdomyolysis. The management of AFib with RVR and rhabdomyolysis requires careful consideration of the patient's overall clinical status, including the presence of heart failure or hypotension. According to the guidelines 1, 2, 3, the following approaches can be considered:

• Calcium channel blockers like diltiazem (0.25 mg/kg IV bolus, then 5-15 mg/hour infusion) are recommended for rate control in AFib with RVR, especially when beta-blockers are contraindicated or not preferred due to concerns about hyperkalemia in rhabdomyolysis.
• Beta-blockers such as metoprolol (5-15 mg IV followed by 25-100 mg oral twice daily) can be used for rate control but with caution in patients with rhabdomyolysis due to the risk of exacerbating hyperkalemia.
• Amiodarone (150 mg IV over 10 minutes, then 1 mg/min for 6 hours) can be considered in patients with heart failure or hypotension, as it is effective for rate control in these situations.
• Aggressive IV fluid hydration is crucial to treat rhabdomyolysis while closely monitoring for fluid overload in cardiac patients.
• Electrolyte abnormalities, particularly potassium, should be closely monitored and corrected as they can worsen arrhythmias.
• The underlying cause of rhabdomyolysis should be identified and addressed to prevent further muscle breakdown.
• Cardiac monitoring is necessary throughout treatment to ensure effective rate control and to watch for complications. The goal of treatment is to achieve rate control, prevent further complications from rhabdomyolysis, and improve the patient's quality of life and survival outcomes.

From the FDA Drug Label

In patients with chronic atrial fibrillation, digoxin slows rapid ventricular response rate in a linear dose-response fashion from 0.25 to 0.75 mg/day.

For Atrial Fibrillation (AFib) with Rapid Ventricular Response (RVR) and Rhabdomyolysis with heart rate increases,

• Digoxin can be given to slow the rapid ventricular response rate.
• The dose of digoxin should be titrated to the minimum dose that achieves the desired ventricular rate control without causing undesirable side effects 4.
• The recommended daily dose of digoxin for adults with atrial fibrillation is between 0.25 to 0.75 mg/day 4.
• However, caution should be exercised when using digoxin in patients with rhabdomyolysis, as renal function may be impaired, affecting digoxin clearance 5.

From the Research

Atrial Fibrillation with Rapid Ventricular Response (RVR) and Rhabdomyolysis with Heart Rate Increases

• Atrial fibrillation (AF) with RVR can lead to complications such as hypoperfusion and cardiac ischemia 6
• Rate or rhythm control should be pursued in hemodynamically stable patients with AF and RVR 6
• Beta blockers or calcium channel blockers can be used for rate control in patients with AF and RVR who do not undergo cardioversion 6

Management of AF with RVR

• Intravenous (IV) diltiazem and metoprolol are commonly used to achieve rate control for AF with RVR 7, 8
• Diltiazem may achieve rate control faster than metoprolol, but both agents seem safe and effective 7
• Metoprolol was associated with a 26% lower risk of adverse events compared to diltiazem 8

Considerations for Patients with Heart Failure with Reduced Ejection Fraction (HFrEF)

• For patients with concomitant HFrEF, beta blockers (BB) are preferred over calcium channel blockers (CCB) due to their potential negative inotropic effects 9
• However, a study found no difference in total adverse events between patients treated with IV diltiazem and metoprolol, but a higher incidence of worsening heart failure symptoms in the diltiazem group 9

Additional Management Strategies

• Digoxin can be added to the regimen to cause a favorable outcome, but is generally inefficacious as a single agent in slowing the ventricular rate in acute AF 10
• Cardioversion is the treatment of choice in unstable or hemodynamically compromised patients with AF and RVR 10
• Radiofrequency ablation of the AV node or anomalous tract may be considered in refractory or high-risk subjects as a last resort 10