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Flecainide Toxicity in a Patient with a Functioning Pacemaker
Sneha Chebrolu1, Jonathan Mayl2, Prashant Bhave2
1Department of Internal Medicine, Wake Forest Baptist Health, Winston-Salem, NC, USA.
The Journal of Innovations in Cardiac Rhythm Management
|July 16, 2024
Summary
Flecainide toxicity, identified by wide QRS complexes, can occur in patients with pacemakers. Adjusting the pacemaker mode (DDD to VVI) resolved tachycardia and improved ECGs in a case study.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Flecainide is a Class Ic anti-arrhythmic drug with use-dependent properties, meaning its efficacy increases at higher heart rates.
- Flecainide toxicity is characterized by wide QRS complexes on an electrocardiogram (ECG).
- Patients with structural heart disease and acute kidney injury are at increased risk for flecainide toxicity.
Observation:
- A 75-year-old patient with a pacemaker presented with suspected flecainide toxicity.
- The initial ECG revealed tachycardia with wide QRS complexes.
- The patient's pacemaker, in DDD mode, exhibited rapid ventricular pacing and failed to mode switch.
Findings:
- Modification of the pacemaker to VVI mode led to the resolution of tachycardia.
- The patient's QRS complexes improved after the pacing mode adjustment.
- This case highlights the use-dependent nature of flecainide.
Implications:
- Pacemaker mode manipulation can be a valuable tool in managing flecainide toxicity.
- Understanding flecainide's use dependence is crucial for patient management.
- This case underscores the importance of considering pacemaker settings in patients with anti-arrhythmic drug toxicity.
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