The Feasibility and Safety of Flecainide Use Among Patients With Varying Degrees of Coronary Disease

The effect of antiarrhythmic medications on the risk of cardiovascular outcomes in patients with atrial fibrillation and coronary artery disease

BACKGROUND

While current guidelines recommend amiodarone and dronedarone for rhythm control in patients with atrial fibrillation (AF) and coronary artery disease (CAD), there was no comparative study of antiarrhythmic drugs (AADs) on the cardiovascular outcomes in general practice.

METHODS

This study included patients with AF and CAD who received their first prescription of amiodarone, class Ic AADs (flecainide, propafenone), dronedarone or sotalol between January 2016 and December 2020. The primary outcome was a composite of hospitalization for heart failure (HHF), stroke, acute myocardial infarction (AMI), and cardiovascular death. We used Cox proportional regression models, including with inverse probability of treatment weighting (IPTW), to estimate the relationship between AADs and cardiovascular outcomes.

RESULTS

Among the AF cohort consisting of 8752 patients, 1996 individuals had CAD, including 477 who took dronedarone and 1519 who took other AADs. After a median follow-up of 38 months, 46.3% of patients who took dronedarone and 54.4% of patients who took other AADs experienced cardiovascular events. Compared to dronedarone, the use of other AADs was associated with increased cardiovascular events after adjusting for covariates (hazard ratio [HR] 1.531, 95% confidence interval [CI] 1.112-2.141, p = 0.023) and IPTW (HR 1.491, 95% CI 1.174-1.992, p = 0.012). The secondary analysis showed that amiodarone and class Ic drugs were associated with an increased risk of HHF. The low number of subjects in the sotalol group limits data interpretation.

CONCLUSION

For patients with AF and CAD, dronedarone was associated with better cardiovascular outcomes than other AADs. Amiodarone and class Ic AADs were associated with a higher risk of cardiovascular events, particularly HHF.

Effect of Flecainide and Ibutilide Alone and in Combination to Terminate and Prevent Recurrence of Atrial Fibrillation

BACKGROUND

There is a need for improved approaches to rhythm control therapy of atrial fibrillation (AF).

METHODS

The effectiveness of flecainide (1.5 µmol/L) and ibutilide (20 nmol/L), alone and in combination, to cardiovert and prevent AF recurrence was studied in canine-isolated coronary-perfused right atrioventricular preparations. We also examined the safety of the combination of flecainide (1.5 µmol/L) and ibutilide (50 nmol/L) using canine left ventricular wedge preparations.

RESULTS

Sustained AF (>1 hour) was inducible in 100%, 60%, 20%, and 0% of atria in the presence of acetylcholine alone, acetylcholine+ibutilide, acetylcholine+flecainide, and acetylcholine+ibutilide+flecainide, respectively. When used alone, flecainide and ibutilide cardioverted sustained AF in 40% and 20% of atria, respectively, but in 100% of atria when used in combination. Ibutilide prolonged atrial and ventricular effective refractory period by 15% and 8%, respectively, at a cycle length of 500 ms (P<0.05 for both). Flecainide increased the effective refractory period in atria by 27% (P<0.01) but by only 2% in the ventricles. The combination of the 2 drugs lengthened the effective refractory period by 42% in atria (P<0.01) but by only 7% (P<0.05) in the ventricles. In left ventricular wedges, ibutilide prolonged QT and Tpeak-Tend intervals by 25 and 55%, respectively (P<0.05 for both; cycle length, 2000 ms). The addition of flecainide (1.5 µmol/L) partially reversed these effects (P<0.05 for both parameters versus ibutilide alone). Torsades de Pointes score was relatively high with ibutilide alone and low with the drug combination.

CONCLUSIONS

In our experimental model, a combination of flecainide and ibutilide significantly improves cardioversion and prevents the recurrence of AF compared with monotherapies with little to no risk for the development of long-QT-mediated ventricular proarrhythmia.

Rationale and Design of a Randomized Controlled Clinical Trial on the Safety and Efficacy of Flecainide versus Amiodarone in the Cardioversion of Atrial Fibrillation at the Emergency Department in Patients with Coronary Artery Disease (FLECA-ED)

Pharmacologic cardioversion is a well-established alternative to electric cardioversion for hemodynamically stable patients, as it skips the risks associated with anesthesia. A recent network meta-analysis identifies the most effective antiarrhythmics for pharmacologic cardioversion with flecainide exhibiting a more efficacious and safer profile towards faster cardioversion. Moreover, the meta-analysis of class Ic antiarrhythmics revealed an absence of adverse events when used for pharmacologic cardioversion of AF in the ED, including patients with structural heart disease. The primary goals of this clinical trial are to prove the superiority of flecainide over amiodarone in the successful cardioversion of paroxysmal atrial fibrillation in the Emergency Department and to prove that the safety of flecainide is non-inferior to amiodarone in patients with coronary artery disease without residual ischemia, and an ejection fraction over 35%. The secondary goals of this study are to prove the superiority of flecainide over amiodarone in the reduction in hospitalizations from the Emergency Department due to atrial fibrillation in the time taken to achieve cardioversion, and in the reduction in the need to conduct electrical cardioversion.