Quinidine for pharmacological cardioversion of atrial fibrillation: a retrospective analysis in 501 consecutive patients.
BACKGROUND
Although quinidine has been used to terminate atrial fibrillation (AFib) for a long time, it has been recently classified to be used as a third-line-drug for cardioversion. However, these recommendations are based on a few small studies, and there are no data available of a larger modern patient population undergoing pharmacological cardioversion of AFib. Therefore, we evaluated the safety of quinidine for cardioversion of paroxysmal AFib in patients after cardiac surgery and coronary intervention.


METHODS
In 501 consecutive patients (66 +/- 9 years, 32% women), 200-400 mg of quinidine were administered every 6 hours until cardioversion or for a maximum of 48 hours. Patients were included with QT interval < or =450 ms, ejection fraction (EF) > or =35%, and plasma potassium >4.3 mEq/L. Exclusion criteria were: unstable angina, myocardial infarction <3 months, and advanced congestive heart failure. Patients received verapamil, beta-blockers, or digitalis to slow down ventricular rate <100 bpm.


RESULTS
Quinidine therapy did not have to be stopped due to adverse drug reactions (ADR), and no significant QTc interval prolongation (Bazett and Fridericia correction) and no life-threatening ventricular arrhythmia occurred. Mean quinidine dose was 617 +/- 520 mg and 92% of the patients received verapamil or beta-blocker to decrease ventricular rate. Cardioversion was successful in 84% of patients. All ADRs were minor and transient. Multivariate analysis revealed female gender (OR 2.62, CI 1.61-4.26, P < 0.001) and EF 45-54% (OR 1.97, CI 1.15-3.36, P = 0.013) as independent risk factors for ADRs.


CONCLUSIONS
Quinidine for pharmacological cardioversion of AFib is safe and well tolerated in this subset of patients.
Schwaab
Bernhard
B
Department of Cardiology and Cardiovascular Rehabilitation, Curschmann Klinik, Timmendorfer Strand, Germany. schwaab@drguth.de
Katalinic
Alexander
A
Böge
Uta Maria
UM
Loh
Jürgen
J
Blank
Peter
P
Kölzow
Tatjana
T
Poppe
Dirk
D
Bonnemeier
Hendrik
H
D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy*; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D016017:Odds Ratio; D011802:Quinidine / Q000009:adverse effects / Q000627:therapeutic use*; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
D000889:Anti-Arrhythmia Agents; D011802:Quinidine