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.