Atrial flutter medical therapy
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Raviteja Guddeti, M.B.B.S. [2]
Overview
The management of atrial flutter is similar to that of atrial fibrillation with primary goals being control of ventricular rate, restoration of sinus rhythm, prevention of recurrent episodes and thromboembolic episodes. In the setting of unstable hemodynamics immediate electrical cardioversion is recommended. because of the high success rate and low complication rate radiofrequency ablation is considered superior to medical therapy in atrial flutter.
Medical Therapy
Treatment goals in the management of atrial flutter include:
- Control of ventricular rate
- Conversion to sinus rhythm
- Prevention of recurrent episodes and prevention of complications
Treatment modalities for atrial flutter include:
Electric Cardioversion
Synchronous direct current (DC) cardioversion is used as the initial treatment strategy in the management of hemodynamically unstable atrial flutter patients in emergency department. External electric cardioversion is effective in more than 90% of the cases and the initial shock strength used is 50 joules biphasic direct current. Sometimes the first shock may convert an atrial flutter to atrial fibrillation, in such cases a second shock preferable of a higher strength is usually given to restore sinus rhythm. Electric cardioversion increases the risk of stroke and hence pre-treatment with a blood thinner is advised if time permits.
AV Nodal Agents
Ventricular rate control is the prime goal in the management of atrial flutter. Drugs like calcium channel blockers (verapamil or diltiazem) or beta-blockers can be used for this. These drugs act as AV node blocking agents and control ventricular rate, thereby preventing tachycardia induced cardiomyopathy. Beta-blockers also have a direct antiarrhythmic effect on the atria. Administration of adenosine reveals flutter waves by blocking the AV node. History of Wolff-Parkinson-White syndrome or pre-excitation syndrome has to be ruled out before administrating, as these agents while acting on AV node can accelerate conduction in the accessory pathways and can precipitate ventricular fibrillation. Digoxin can also be used as an AV blocking agent in combination with calcium channel blockers and beta-blockers in the event of failure of electric cardioversion, atrial pacing and pharmacologic therapy.
Antiarrhythmic Agents
Class III agents like ibutilide, dofetilide, sotalol or amiodarone are typically used for pharmacologic cardioversion in the treatment of atrial flutter. Intravenous ibutilide is very effective in controlling acute atrial flutter episode and is found to be effective in at least 63% patients. Patients who are administered i.v ibutilide should be monitored using an EKG for at least 4 hrs after the infusion as ibutilide is known to cause QT prolongation and torsades de pointes.
Class IC agents like propafenone or flecainide have also shown to be effective in the conversion of acute onset atrial flutter to normal sinus rhythm.
Rapid Atrial Pacing[1]
As external electrical cardioversion requires anesthesia some doctors prefer atrial overdrive pacing to terminate episodes of atrial flutter. In overdrive pacing the atria are continuously paced at a rate higher than that of the patient's sinus node, which causes an alteration in the atrial rate, propagation and also suppresses the automaticity caused by electrical remodeling in the diseased fibers. Unsuccessful pacing can be due to:
- Insufficient rate and duration of pacing
- Bad electrode contact in the atrium
- Insufficient outlet current