Cardioversjon

Cardioversjon is a medical procedure used to restore a normal heart rhythm in selected arrhythmias, most commonly atrial fibrillation and atrial flutter, and less often certain supraventricular tachycardias. It can be performed electrically or pharmacologically.

Electrical cardioversion delivers a synchronized electrical shock to the heart, typically with external pads placed on the chest or back. The shock is timed to the R wave to avoid disturbing the heart during vulnerable moments. Sedation or anesthesia is usually given, and heart rhythm is monitored throughout. Pharmacological cardioversion uses antiarrhythmic medications, given orally or intravenously, to achieve restoration of sinus rhythm. Drugs commonly used include amiodarone, flecainide, propafenone, and ibutilide, with choice depending on the type of arrhythmia and patient factors.

Indications include unstable patients with tachyarrhythmias requiring rapid rhythm control, and stable patients where rapid restoration of sinus rhythm is desired or where rate control has failed. In atrial fibrillation or flutter lasting more than 48 hours or of unknown duration, anticoagulation for several weeks before elective cardioversion is recommended to reduce stroke risk, or a transesophageal echocardiography–guided approach may be used to assess for left atrial thrombus.

Risks include thromboembolism, particularly if anticoagulation is inadequate, as well as arrhythmias, myocardial injury, skin burns, hypotension, and in some antiarrhythmic drugs, proarrhythmia or organ toxicity. After a successful cardioversion, anticoagulation is often continued for weeks, and long-term rhythm control or rate control strategies may be pursued to reduce recurrence.

See also: defibrillation, ablation, anticoagulation in atrial fibrillation.