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Atrial fibrillation: antiarrhythmics for maintaining sinus rhythm after cardioversion


Atrial fibrillation is the most frequent sustained arrhythmia. Atrial fibrillation frequently recurs after restoration of normal sinus rhythm.
Antiarrhythmic drugs have been widely used to prevent recurrence, but the effect of these drugs on mortality and other clinical outcomes is unclear.
This is an update of a review previously published in 2008 and 2012.

The objective was to determine in patients who have recovered sinus rhythm after having atrial fibrillation, the effects of long-term treatment with antiarrhythmic drugs on death, stroke, embolism, drug adverse effects and recurrence of atrial fibrillation.

In this update three new studies, with 534 patients, were included making a total of 59 included studies comprising 21,305 patients.
All included studies were randomised controlled trials.
Allocation concealment was adequate in 17 trials, it was unclear in the remaining 42 trials.
Risk of bias was assessed in all domains only in the trials included in this update.

Compared with controls, class IA drugs Quinidine and Disopyramide ( odds ratio, OR=2.39, 95% confidence interval [ 95% CI ] 1.03 to 5.59, number needed to treat to harm [ NNTH ] 109, 95% CI 34 to 4985 ) and Sotalol ( OR=2.23, 95% CI 1.1 to 4.50, NNTH=169, 95% CI 60 to 2068 ) were associated with increased all-cause mortality.
Other antiarrhythmics did not seem to modify mortality, but the data could be underpowered to detect mild increases in mortality for several of the drugs studied.

Several class IA ( Disopyramide, Quinidine ), IC ( Flecainide, Propafenone ) and III ( Amiodarone, Dofetilide, Dronedarone, Sotalol ) drugs significantly have reduced recurrence of atrial fibrillation ( OR=0.19 to 0.70, number needed to treat to beneft [ NNTB ] 3 to 16 ).

Beta-blockers ( Metoprolol ) also significantly reduced atrial fibrillation recurrences ( OR=0.62, 95% CI 0.44 to 0.88, NNTB=9 ).

All analysed drugs increased withdrawals due to adverse affects and all but Amiodarone, Dronedarone and Propafenone increased pro-arrhythmia.

Only 11 trials reported data on stroke. None of them found any significant difference with the exception of a single trial than found less strokes in the group treated with Dronedarone compared to placebo. This finding was not confirmed in others studies on Dronedarone.

Researchers could not analyse heart failure and use of anticoagulation because few original studies reported on these measures.

In conclusion, several class IA, IC and III drugs, as well as class II drugs ( beta-blockers ), are moderately effective in maintaining sinus rhythm after conversion of atrial fibrillation.
However, they increase adverse events, including pro-arrhythmia, and some of them ( Disopyramide, Quinidine and Sotalol ) may increase mortality.
Possible benefits on clinically relevant outcomes ( stroke, embolism, heart failure ) remain to be established. ( Xagena )

Lafuente-Lafuente C et al, Cochrane Database Syst Rev. 2015 Mar 28;3:CD005049. doi: 10.1002/14651858.CD005049.pub4.

XagenaMedicine_2015



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