Will cardioversion (cardioversion) cause a stroke in patients with acute atrial fibrillation (AFib)?

From the Guidelines

Cardioversion for acute atrial fibrillation carries a small risk of stroke, but this risk can be minimized with proper precautions, and anticoagulation should be given for at least 3 weeks before cardioversion or a transesophageal echocardiogram (TEE) should be performed to rule out clots in the heart, as recommended by the 2018 Chest guideline and expert panel report 1. The stroke risk is approximately 0.5-1.6% without anticoagulation. If the atrial fibrillation has been present for less than 48 hours, cardioversion can typically be performed without prior anticoagulation. However, if the duration is unknown or greater than 48 hours, anticoagulation is necessary to reduce the risk of stroke. Some key points to consider include:

• Anticoagulation should be continued for at least 4 weeks after successful cardioversion, as stated in the 2018 Chest guideline and expert panel report 1.
• Common anticoagulants used include warfarin (with target INR 2-3), direct oral anticoagulants like apixaban (5mg twice daily), rivaroxaban (20mg daily), dabigatran (150mg twice daily), or edoxaban (60mg daily) 1.
• The stroke risk occurs because during atrial fibrillation, blood can pool in the left atrium and form clots, which may dislodge during cardioversion when normal heart rhythm is restored.
• Patients with additional risk factors such as heart failure, hypertension, diabetes, previous stroke, or advanced age have higher stroke risk and require more careful management, as emphasized in the 2016 ESC guidelines for the management of atrial fibrillation 1.

From the Research

Cardioversion and Stroke Risk in Acute Atrial Fibrillation

• The risk of thromboembolism associated with acute cardioversion of patients with atrial fibrillation (AF) of less than 48 hours duration is low, but varies widely depending on patient characteristics 2.
• Using the CHA2DS2-VASc score may allow better selection of appropriate patients to prevent exposing specific patient groups to an unacceptably high risk of a potentially devastating complication 2.
• Effective periprocedural anticoagulation is the mainstay in thromboembolic complication prevention, and the first week after rhythm conversion is the most vulnerable period 3.
• Early timing of cardioversion appears to be another important measure to decrease the risk of thromboembolic complications 3, 4.
• Transoesophageal echocardiography can identify patients at low risk for a cardioversion-related embolic event and allows cardioversion to be performed earlier, thereby minimizing atrial remodeling 4.

Anticoagulation and Cardioversion

• Current guidelines recommend anticoagulation prior to cardioversion in patients with atrial fibrillation of >48 hours or unknown duration to reduce thromboembolic risk 5.
• Therapeutic anticoagulation with warfarin, with INR between 2 and 3, is consistently achieved in approximately 60% of patients 5.
• Novel oral anticoagulants (NOAC) may be associated with a lower risk of bleeding complications compared to warfarin 5.
• The intensity of periprocedural anticoagulation and the timing of cardioversion appear to be significant determinants of the risk of thromboembolism 3.

Patient Selection and Risk Stratification

• Patient characteristics, such as CHADSVASC score, should be taken into account when assessing the safety of cardioversion 5, 2.
• The probability of early treatment failure and antiarrhythmic treatment options to prevent recurrences should be carefully evaluated to avoid the risks of repeated futile cardioversions 3.
• Awareness of the clinical aspects influencing cardioversion safety should be raised to improve patient outcomes 3.