What is the treatment for unstable atrial (a) flutter using cardioversion?

From the Guidelines

Unstable atrial flutter requires immediate cardioversion to restore normal heart rhythm, and according to the most recent guidelines 1, synchronized cardioversion is recommended for acute treatment of patients with atrial flutter who are hemodynamically unstable and do not respond to pharmacological therapies. For patients showing signs of hemodynamic instability (hypotension, chest pain, altered mental status, or heart failure), synchronized electrical cardioversion should be performed without delay. The recommended initial energy level is 50-100 joules using a biphasic defibrillator. If the first shock is unsuccessful, energy can be escalated to 150-200 joules for subsequent attempts. Prior to cardioversion, ensure the patient receives appropriate sedation such as midazolam 1-2 mg IV or etomidate 0.1-0.2 mg/kg IV unless the situation is immediately life-threatening. After successful cardioversion, patients should be started on rate control medications like beta-blockers (metoprolol 25-100 mg twice daily) or calcium channel blockers (diltiazem 120-360 mg daily in divided doses) to prevent recurrence. Anticoagulation therapy should also be considered based on the patient's CHA₂DS₂-VASc score to prevent thromboembolism, as recommended by the 2018 Chest guideline 1, which suggests therapeutic anticoagulation with well-managed VKA (INR 2-3) or an NOAC using dabigatran, rivaroxaban, edoxaban, or apixaban for at least 3 weeks before cardioversion or a transesophageal echocardiography (TEE)-guided approach with abbreviated anticoagulation before cardioversion. Cardioversion is effective because it delivers an electrical shock that depolarizes the entire myocardium simultaneously, interrupting the reentry circuit that sustains atrial flutter and allowing the sinoatrial node to resume control of cardiac rhythm. Some key points to consider in the management of unstable atrial flutter include:

• The importance of immediate cardioversion in hemodynamically unstable patients
• The use of anticoagulation therapy to prevent thromboembolism
• The role of rate control medications in preventing recurrence
• The potential risks and benefits of pharmacological cardioversion versus electrical cardioversion, as discussed in the 2015 ACC/AHA/HRS guideline 1.

From the FDA Drug Label

Among patients with atrial flutter, 53% receiving 1 mg ibutilide fumarate and 70% receiving 2 mg ibutilide fumarate converted, compared to 18% of those receiving sotalol Conversion of atrial flutter/ fibrillation usually (70% of those who converted) occurred within 30 minutes of the start of infusion and was dose related. Electrical cardioversion was allowed 90 minutes after the infusion was complete.

The treatment for unstable atrial (a) flutter using cardioversion with ibutilide fumarate is:

• Intravenous infusion of ibutilide fumarate at a dose of 1 mg or 2 mg.
• Conversion of atrial flutter usually occurs within 30 minutes of the start of infusion.
• Electrical cardioversion is allowed 90 minutes after the infusion is complete 2.

From the Research

Treatment for Unstable Atrial Flutter using Cardioversion

The treatment for unstable atrial flutter using cardioversion involves several approaches, including:

• Electrical cardioversion: This method is highly effective in converting atrial flutter to sinus rhythm, with success rates of up to 100% 3.
• Pharmacological cardioversion: This approach uses antiarrhythmic drugs such as procainamide, ibutilide, and amiodarone to convert atrial flutter to sinus rhythm. However, the efficacy of these drugs varies, with ibutilide showing efficacy rates of 38-76% 4, 5.
• DC-cardioversion: This method is indicated in patients with unstable hemodynamics and can successfully cardiovert atrial flutter to sinus rhythm with energies less than 50 joules 4, 5.

Key Considerations

When using cardioversion to treat unstable atrial flutter, several key considerations must be taken into account, including:

• Peri-procedural anticoagulation: This is necessary to prevent thromboembolism, especially in patients with chronic atrial fibrillation or atrial flutter 6.
• Risk factors for recurrence: These include the duration of atrial flutter, the presence of underlying heart disease, and the use of antiarrhythmic drugs 7.
• Success rate: The success rate of cardioversion varies depending on the method used, with electrical cardioversion being more effective than pharmacological cardioversion 3.

Antiarrhythmic Drugs

Several antiarrhythmic drugs can be used to treat unstable atrial flutter, including:

• Ibutilide: This drug has been shown to be effective in converting atrial flutter to sinus rhythm, with efficacy rates of 38-76% 4, 5.
• Amiodarone: This drug has a conversion rate of up to 80% in atrial fibrillation and is also effective in treating ventricular tachyarrhythmias 4, 5.
• Procainamide: This drug can be used to convert atrial flutter to sinus rhythm, but its efficacy is lower than that of ibutilide and amiodarone 3, 4, 5.