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

Propafenone- vs. amiodarone-associated adverse cardiac outcomes in patients with atrial fibrillation and heart failure

AIMS

Clinical trials have shown an increased risk of death in patients with recent myocardial infarction who received antiarrhythmic drugs such as flecainide, encainide or moricizine, especially in the presence of associated structural heart disease such as cardiac dysfunction. This study aimed to evaluate the safety outcomes of propafenone use in atrial fibrillation patients with heart failure when compared to those of amiodarone use.

METHODS

This population-based cohort study used the National Health Insurance Research Database in Taiwan. Eligible patients were those who had atrial fibrillation or atrial flutter diagnosis, had heart failure diagnosis, and first received propafenone or amiodarone between 2002 and 2018. The primary endpoints were death due to arrhythmia and the composite proarrhythmic outcome, which consisted of sudden cardiac arrest, arrhythmic death, ventricular arrhythmia and implantation of defibrillator.

RESULTS

After propensity score matching, the study cohort consisted of 7235 propafenone and 14 470 amiodarone users. Compared to amiodarone, propafenone was associated with significantly lower risk of the composite proarrhythmic outcome (adjusted hazard ratio: 0.52; 95% confidence interval: 0.42-0.64; P < .001). Propafenone users also had lower risk of death owing to arrhythmia compared to amiodarone users (adjusted hazard ratio: 0.22; 95% confidence interval: 0.08-0.65; P = .006). Subgroup analysis and sensitivity analysis showed similar trends, favouring propafenone.

CONCLUSION

Propafenone was not significantly associated with increased risk of proarrhythmia and mortality when compared to amiodarone in atrial fibrillation patients with heart failure in contemporary real-world settings. Prospective studies are needed to determine whether propafenone should definitely be avoided in these patients.

Late gadolinium enhancement in mid infero-septal area after left bundle branch area pacing in the setting of bifascicular block and syncope: a case report

Background

Conduction system pacing, which includes His bundle pacing and left bundle branch area pacing (LBBAP), is becoming increasingly common in clinical practice. His bundle pacing, introduced over two decades ago, continues to see growing use, while LBBAP is gaining traction due to its broader target area and shorter procedure times. However, complications such as septal perforation and lead-related issues may still arise. This case report explores the evaluation and management of recurrent syncope in the context of bifascicular block (BFB), highlighting the importance of thorough assessment, continuous ECG monitoring, and the potential need for permanent pacemaker implantation.

Case summary

A 60-year-old woman with a history of myocardial infarction, Type II diabetes, and dyslipidaemia presented with recurrent syncope and BFB, for which a LBBAP device was implanted in August 2023. In February 2024, she was admitted again due to recurrent syncope and frequent premature ventricular contractions. Cardiac magnetic resonance imaging revealed two localized myocardial scars: one at the basal anterior wall from the 2018 ischaemic event and another in the mid infero-septal wall at the site of the LBBAP lead. During her hospital stay, she experienced multiple episodes of near fainting due to orthostatic hypotension, indicative of underlying autonomic neuropathy.

Discussion

This narrative explores the evolving landscape of cardiac pacing techniques, with a focus on LBBAP, highlighting its advantages over traditional methods while also acknowledging potential complications. Additionally, it emphasizes the importance of a comprehensive workup for syncope and the need for tailored interventions that extend beyond pacemaker implantation.

Evolution in electrophysiology 100 years after Einthoven: translational and computational innovations in rhythm control of atrial fibrillation

In 1924, the Dutch physiologist Willem Einthoven received the Nobel Prize in Physiology or Medicine for his discovery of the mechanism of the electrocardiogram (ECG). Anno 2024, the ECG is commonly used as a diagnostic tool in cardiology. In the paper 'Le Télécardiogramme', Einthoven described the first recording of the now most common cardiac arrhythmia: atrial fibrillation (AF). The treatment of AF includes rhythm control, aiming to alleviate symptoms and improve quality of life. Recent studies found that early rhythm control might additionally improve clinical outcomes. However, current therapeutic options have suboptimal efficacy and safety, highlighting a need for better rhythm-control strategies. In this review, we address the challenges related to antiarrhythmic drugs (AADs) and catheter ablation for rhythm control of AF, including significant recurrence rates and adverse side effects such as pro-arrhythmia. Furthermore, we discuss potential solutions to these challenges including novel tools, such as atrial-specific AADs and digital-twin-guided AF ablation. In particular, digital twins are a promising method to integrate a wide range of clinical data to address the heterogeneity in AF mechanisms. This may enable a more mechanism-based tailored approach that may overcome the limitations of previous precision medicine approaches based on individual biomarkers. However, several translational challenges need to be addressed before digital twins can be routinely applied in clinical practice, which we discuss at the end of this narrative review. Ultimately, the significant advances in the detection, understanding, and treatment of AF since its first ECG documentation are expected to help reduce the burden of this troublesome condition.

Mechanisms of Chemical Atrial Defibrillation by Flecainide and Ibutilide

BACKGROUND

Effective and safe pharmacological approaches for atrial defibrillation offer several potential advantages over techniques like ablation. Pharmacological therapy is noninvasive, involving no risk associated with the procedure or resulting complications. Moreover, acute drug intervention with existing drugs is likely to be low cost and broadly accessible, thereby addressing a central tenet of health equity.

OBJECTIVES

This study aims to investigate ibutilide-mediated action potential prolongation to promote use-dependent effects of flecainide on Na+ channels by reducing the diastolic interval and, consequently, drug unbinding to reduce action potential excitability in atrial tissue and terminate re-entrant arrhythmia.

METHODS

The authors utilize a modeling and simulation approach to predict the specific combinations of sodium- and potassium-channel blocking drugs to chemically terminate atrial re-entry.

RESULTS

Computational modeling and simulation show that acute application of flecainide and ibutilide is a promising example of drug repurposing that may constitute a promising combination for chemical atrial defibrillation.

CONCLUSIONS

We predict the drug concentrations that promote efficacy of flecainide and ibutilide used in combination for atrial chemical defibrillation. We also predict the potential safety pharmacology impact of this drug combination on ventricular electrophysiology.

Flecainide toxicity with pill-in-pocket approach from accidental overdose: a case report

Background

The Pill-in-the-Pocket (PiP) approach may be used in highly selected patients to achieve acute pharmacological cardioversion into sinus rhythm. Flecainide toxicity is rarely reported, especially with patients who take flecainide as PiP, and only limited evidence exists in its management. We present a case of accidental flecainide overdose for a patient who is on PiP and the acute management strategy.

Case summary

A 78-year-old female with persistent atrial fibrillation (AF), previously underwent pulmonary vein isolation and maintained on verapamil 240 mg twice daily, presented to the electrophysiology clinic following a recent hospital admission for recurrent AF. Due to infrequent recurrent episodes of symptomatic AF, the patient preferred to avoid both repeat ablation and additional daily medications. After an initial trial on telemetric monitoring, a PiP approach with flecainide 300 mg was adopted. Unfortunately, palpitations and dyspnoea in the context of chronic obstructive pulmonary disease exacerbation led the patient to self-medicate with multiple doses of albuterol and flecainide. Twelve-lead electrocardiogram showed slow AF with a wide QRS complex. The patient received 1 g of calcium gluconate with a 180 mEq bolus of sodium bicarbonate 8.4% and was started on continuous sodium bicarbonate infusion at 150 mL/h. Over a 12 h period, the QRS complex narrowed down, and the rhythm returned to normal sinus rhythm with a QRS interval of 136 ms.

Discussion

The PiP strategy with flecainide is safe and effective. Reinforcement of medication dosing and frequency with patient read back is key to avoid accidental toxicity, which could be life-threatening. Treatment with sodium bicarbonate is quick and highly effective.

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.