What medications should be given prior to cardioversion?

From the Guidelines

Prior to cardioversion, patients with atrial fibrillation or flutter should receive anticoagulation therapy to reduce the risk of thromboembolism, with direct oral anticoagulants (DOACs) recommended in preference to vitamin K antagonists (VKAs) in eligible patients. For non-emergent cardioversion, anticoagulation with a DOAC such as apixaban (5mg twice daily), rivaroxaban (20mg daily), dabigatran (150mg twice daily), or edoxaban (60mg daily) should be given for at least 3 weeks before the procedure and continued for at least 4 weeks afterward 1. The use of DOACs is preferred due to their favorable risk-benefit profile compared to VKAs, as stated in the 2024 ESC guidelines for the management of atrial fibrillation 1.

Some key points to consider when administering anticoagulation therapy prior to cardioversion include:

• The duration of anticoagulation therapy, which should be at least 3 weeks before cardioversion and at least 4 weeks after cardioversion 1
• The use of transoesophageal echocardiography to rule out left atrial thrombi if anticoagulation therapy has not been given for at least 3 weeks 1
• The importance of continuing anticoagulation therapy for at least 4 weeks after cardioversion, regardless of whether sinus rhythm is achieved 1

It is also important to note that for emergent cardioversion, intravenous heparin or low molecular weight heparin should be administered immediately, followed by oral anticoagulation 1. Sedation is typically provided using short-acting agents such as midazolam, propofol, or etomidate. Anticoagulation is crucial because cardioversion can dislodge existing clots in the atria, particularly the left atrial appendage, which could lead to stroke or systemic embolism if not properly managed.

The most recent and highest quality study, the 2024 ESC guidelines for the management of atrial fibrillation, recommends the use of DOACs in preference to VKAs in eligible patients undergoing cardioversion 1. This recommendation is based on the favorable risk-benefit profile of DOACs compared to VKAs, and the importance of reducing the risk of thromboembolism in patients undergoing cardioversion.

From the FDA Drug Label

5 mg should be given over a period of no less than 2 minutes. Wait an additional 2 or more minutes to fully evaluate the sedative effect. If concomitant CNS depressant premedications are used in these patients, they will require at least 50% less midazolam than healthy young unpremedicated patients Unpremedicated Patients: In the absence of premedication, an average adult under the age of 55 years will usually require an initial dose of 0.3 to 0. 35 mg/kg for induction, administered over 20 to 30 seconds and allowing 2 minutes for effect. Premedicated Patients: When the patient has received sedative or narcotic premedication, particularly narcotic premedication, the range of recommended doses is 0.15 to 0.35 mg/kg.

Medications to give prior to cardioversion:

• Midazolam: 0.15 to 0.35 mg/kg for premedicated patients and 0.3 to 0.35 mg/kg for unpremedicated patients, administered over 20 to 30 seconds
• Consider narcotic premedication such as fentanyl (1.5 to 2 mcg/kg intravenous) or morphine (dosage individualized, up to 0.15 mg/kg intramuscular)
• Consider sedative premedications such as hydroxyzine pamoate (100 mg orally) or sodium secobarbital (200 mg orally) 2

From the Research

Medications Prior to Cardioversion

To minimize the risk of stroke and other complications, certain medications are recommended prior to cardioversion for atrial fibrillation. These include:

• Anticoagulants such as warfarin, with a target International Normalized Ratio (INR) of 2-3 for at least 3 weeks before cardioversion 3, 4
• Target-specific oral anticoagulants (TSOAs) like dabigatran, apixaban, and rivaroxaban, which may be effective alternatives to warfarin 5, 6
• Other medications like amiodarone, flecainide, propafenone, and sotalol may be used for conversion to sinus rhythm or to control heart rate 7

Anticoagulation Therapy

Anticoagulation therapy is crucial before cardioversion to prevent thromboembolic events. The choice of anticoagulant depends on various factors, including the patient's risk of stroke and bleeding.

• Warfarin has been traditionally used, but its use requires regular monitoring of INR levels 3, 4
• TSOAs like dabigatran and apixaban have been shown to be effective and safe alternatives to warfarin, with the advantage of not requiring regular monitoring 5, 6

Timing of Cardioversion

The timing of cardioversion depends on the patient's condition and the chosen anticoagulation therapy.

• With warfarin, cardioversion is typically delayed until the patient has been therapeutically anticoagulated for at least 3 weeks 3, 4
• With TSOAs, cardioversion can be performed sooner, as these medications have a faster onset of action 5, 6