The use of oral ranolazine to convert new or paroxysmal atrial fibrillation: a review of experience with implications for possible "pill in the pocket" approach to atrial fibrillation.
BACKGROUND
Atrial fibrillation (AF) is the most common arrhythmia requiring treatment. High dose oral anti-arrhythmics may cardiovert some paroxysmal AF. This "pill in pocket" approach has allowed patients to treat themselves on an as needed basis. Pro-arrhythmic concerns have limited the usefulness of this approach to patients without structural heart disease. Ranolazine is an anti-anginal agent, which inhibits abnormal late Na+ channel currents in cardiomyocytes and decreases sodium-calcium overload. Ranolazine is a potent inhibitor of after-depolarizations, which have been implicated in the initiation and propagation of AF. Because ranolazine has no known pro-arrhythmic effects, it could be useful as a safe "pill in the pocket" agent if it were effective in converting AF. We describe our experience using oral ranolazine to convert new or paroxysmal AF.


METHODS
2000 mg of ranolazine were administered to 18 patients with new (11 patients) or paroxysmal (7 patients) AF of at least 3, but not greater than 48 hours duration. Most patients (14) were in the hospital at the time ranolazine was administered. Age, sex, echocardiographic data, associated health conditions and structural heart disease were recorded. Successful conversion was defined as restoring sinus rhythm within 6 hours of ranolazine administration.


RESULTS
All but 1 patient had some form of structural heart disease and all but 2 patients had left atrial enlargement. Thirteen of 18 patients converted to sinus rhythm. No pro-arrhythmic effects, hemodynamic instability, adverse rate effects, or perceived intolerance (other than constipation) were noted. The 72% conversion rate was comparable to other reported "pill in the pocket" protocols.


CONCLUSIONS
High dose oral ranolazine shows utility as a possible safe agent to convert new or paroxysmal AF. Lack of blinded controls and small numbers limits the power of this observation.
Murdock
David K
DK
The Aspirus Heart and Vascular Institute, Cardiovascular Associates of Northern Wisconsin and The CaRE Foundation, Wausau Wisconsin 54403, USA. dkmurdock@charter.net
Kersten
Mary
M
Kaliebe
Jeff
J
Larrain
German
G