Flecainide-Induced Left Bundle Branch Block.
Swetha R Nuthulaganti1, Yixin Zhang1, Temitope Akinjogbin2
1Internal Medicine, University of Florida College of Medicine - Jacksonville, Jacksonville, USA.
Cureus
|May 27, 2022
Summary
Flecainide, a common antiarrhythmic drug, can paradoxically induce new left bundle branch block (LBBB) in patients. This case highlights the importance of monitoring for adverse cardiac events during flecainide therapy.
Area of Science:
- Cardiology
- Electrophysiology
- Pharmacology
Background:
- Flecainide is a first-line Class IC antiarrhythmic medication for patients without structural heart disease.
- It functions by inhibiting the inward sodium current via voltage-gated calcium channel blockade in cardiac membranes.
- This drug is known to slow conduction, particularly in cases of left bundle branch block.
Observation:
- A case study is presented involving a patient who developed a new left bundle branch block (LBBB).
- This adverse cardiac event occurred following the administration of flecainide.
- The development of LBBB was unmonitored, posing potential risks.
Findings:
- Flecainide use was directly associated with the onset of a new left bundle branch block (LBBB).
- This finding contrasts with the drug's known effect of slowing conduction in pre-existing LBBB.
- Unmonitored toxicity of flecainide can lead to serious complications like ventricular dyssynchrony or fatal arrhythmias.
Implications:
- This case underscores the potential for flecainide to induce new conduction abnormalities, including LBBB.
- Careful patient monitoring is crucial during flecainide treatment to detect and manage adverse effects.
- Clinicians should be aware of this paradoxical effect to ensure patient safety and optimize antiarrhythmic therapy.
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