Pharmacological cardioversion for atrial fibrillation

Pharmacological cardioversion effectively restores sinus rhythm in approximately 50% of patients with recent-onset atrial fibrillation. Procedural sedation is not required before pharmacological cardioversion.

Pharmacological cardioversion has an inherent risk of causing thromboembolic events, such as stroke. To significantly reduce that risk, immediately start anticoagulant therapy in patients not already therapeutically anticoagulated. If atrial fibrillation has persisted for less than 48 hours, pharmacological cardioversion can be performed without delay. If atrial fibrillation has persisted for longer than 48 hours, or if the duration is unknown, cardioversion should be deferred until the patient has had a minimum of 3 weeks of anticoagulant therapy, unless transoesophageal echocardiography (TOE) has ruled out atrial thrombusJanuary, 2019National Institute for Health and Care Excellence (NICE), 2021.

For anticoagulation before pharmacological cardioversion, use UFH, LMWH or DOACs; follow a local protocol for dosing of anticoagulants for pharmacological cardioversion, or, if a local protocol is unavailable, see direct-acting oral anticoagulants to prevent thromboembolic events in atrial fibrillation, or parenteral anticoagulants for VTE treatmentJanuary, 2019.

Anticoagulant therapy should be used for at least 4 weeks following pharmacological cardioversion; see Anticoagulant therapy to prevent thromboembolic events in atrial fibrillation for dosages.

For a patient with atrial fibrillation who has a left ventricular ejection fraction known to be greater than 40% and no significant coronary artery disease, flecainide is preferred for pharmacological cardioversion. A suitable regimen is:

For a patient with atrial fibrillation who has a left ventricular ejection fraction of 40% or less, or coronary artery disease, amiodarone is preferred for pharmacological cardioversion. A suitable regimen is:

‘Pill-in-the-pocket’ cardioversion refers to the use of a single oral dose of flecainide to restore sinus rhythm; it is self-administered by patients at home. Pill-in-the-pocket cardioversion is used under specialist supervision by selected patients with infrequent symptomatic episodes of atrial fibrillationHindricks, 2021. The flecainide dose is best taken in combination with a single dose of an AV nodal blocking drug (eg a beta blocker, diltiazem, verapamil) to decrease the risk of conversion to atrial flutter with 1:1 conduction.