SHM Converge Scientific Abstract ePoster Gallery-When the Rhythm Goes Wide: Acute Flecainide Toxicity

Pdf Summary

This case report describes acute flecainide toxicity in an 80-year-old woman with atrial fibrillation and heart failure with preserved ejection fraction. She had been taking high-dose flecainide (150 mg twice daily) for several years after pulmonary vein isolation. During hospitalization for a lower extremity ulcer, she developed bacteremia and acute kidney injury. Her initial ECG showed a wide-complex tachycardia with marked QRS prolongation (210 ms) and prolonged QTc (526 ms), raising concern for flecainide toxicity, especially given the acute renal dysfunction.<br /><br />Flecainide is a Class Ic antiarrhythmic that is partly renally excreted and is not dialyzable, making toxicity more likely in patients with impaired kidney function. In this patient, flecainide was stopped and high-dose metoprolol was used for rate control. Her QRS duration normalized overnight, and she remained in sinus rhythm. Because of her renal disease, she was transitioned to amiodarone for ongoing rhythm control. She was discharged with flecainide discontinued, metoprolol increased, and anticoagulation continued.<br /><br />The report highlights that severe flecainide toxicity can present with wide QRS complexes, bundle branch block patterns, prolonged QTc, and hemodynamic risk, particularly when QRS exceeds 200 ms. It also emphasizes the importance of recognizing drug toxicity early in the emergency and inpatient settings, especially when renal function worsens. The authors note that while flecainide remains an effective option for atrial fibrillation in patients without structural heart disease, clinicians must monitor carefully for adverse effects and adjust therapy during acute illness or renal impairment.

Asset Subtitle

Kengo Z. Soghoyan

Meta Tag

Author List Anthony Voelkel, Ashwani K. Bedi, John R. Majewski, Kengo Z. Soghoyan, Robert D. Ficalora, Shaleen Ayers

Category Clinical Vignettes

Concept Flecainide

Concept Flecainide Toxicity

Concept Wide-Complex Tachycardia

Concept Renal Dysfunction

Concept Left Bundle Branch Block

Distinguished Non-Finalist

Presenter Organization Indiana University

Presenting Author Kengo Z. Soghoyan

Track Adult

Keywords

flecainide toxicity

atrial fibrillation

acute kidney injury

wide-complex tachycardia

QRS prolongation

QTc prolongation

renal dysfunction

Class Ic antiarrhythmic

amiodarone

heart failure with preserved ejection fraction

Flecainide

Flecainide Toxicity

Wide-Complex Tachycardia

Renal Dysfunction

Left Bundle Branch Block