Introduction
Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide and represents a major burden to health care systems.1
Rhythm control is the preferred strategy in patients with symptomatic AF. Electrical cardio-version (ECV) and pharmacological cardio-version (PCV) are widely used in order to restore sinus rhythm (SR). ECV is more effective than PCV, particularly in persistent AF 2, and while proven to be a safe, in some cases it could lead to serious adverse events, including QT prolongation and Torsade de pointes.3,4
It has been suggested that persistent AF induces ventricular repolarization remodeling leading to transient QT prolongation following ECV.5 This might increase the risk for Torsades de pointes, especially when other QT prolonging conditions exists.4 Furthermore, the European Heart Society and the American Heart Society guidelines recommend the initiation of antiarrhythmic drug therapy 1-3 days before electrical cardioversion to promote sustainable cardioversion.6,7 In fact, many of these drugs have a potential of further QTc prolongation, increasing the risk even more.8 Currently, there are no guidelines specifying the time needed to monitor patients following CV. The common practice is to watch the patients for 1-2 hours following CV, and thereafter to discharge them.
We hypothesized that patients with persistent atrial fibrillation on antiarrhythmic treatment might develop significant QTc prolongation following CV during long-term monitoring. Therefore, in this prospective clinical study we aimed to 1) assess changes in QTc following cardioversion and to identify the time to maximal QTc prolongation, 2) to compare the current standard of care to 7-days Holter monitoring, and 3) to identify clinical predictors for clinically significant QTc prolongation.