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Updated: Nov 14, 2025
Noninvasive Electrocardiography in the Perinatal Mouse
Published on: June 12, 2020
A frightening giant QRS complex in a 3-months-old infant
Anna Correra1, Assunta Merola2, Michela Palma2
1Adult Congenital Heart Disease Unit, Monaldi Hospital, Naples, Italy.
Insights
An infant experienced Flecainide toxicity due to accidental overdose. Prompt hydration and monitoring led to significant QRS complex normalization, resolving the critical condition.
Area of Science:
- Pediatrics
- Clinical Toxicology
- Cardiology
Background:
- Flecainide is a Class Ic antiarrhythmic drug.
- Accidental medication overdoses in infants can lead to severe toxicity.
- Cardiac conduction abnormalities are a hallmark of Flecainide toxicity.
Purpose of the Study:
- To report a case of Flecainide overdose in an infant.
- To describe the clinical presentation and electrocardiographic findings.
- To illustrate the management and outcome of Flecainide toxicity.
Main Methods:
- Case report of a 3-month-old infant with accidental Flecainide overdose.
- Clinical assessment including ECG and serum Flecainide level measurement.
- Management with continuous hydration and close monitoring.
Main Results:
- ECG revealed sinus rhythm with prolonged AV interval (200 ms) and wide QRS complexes (280 ms).
- Serum Flecainide level confirmed intoxication (1.2 μg/ml).
- Within 3 hours of hydration, QRS narrowed to 150 ms; near normalization within 24 hours.
Conclusions:
- Accidental Flecainide overdose in infants can cause significant cardiac conduction disturbances.
- Aggressive hydration and monitoring are effective in managing Flecainide toxicity.
- Early recognition and intervention are crucial for favorable outcomes in pediatric drug intoxication.
Abstract:
A 3-months-old infant was urgently admitted for drowsiness and lack of appetite started 24 h before. The ECG showed sinus rhythm with a prolonged AV interval (200 ms) and very large QRS complexes (280 ms) due to Flecainide overdosing following incorrectly administration for poor communication between parents resulted in both giving a dose to the infant. Flecainide serum level was 1.2μg/ml, confirming the diagnosis of an accidental drug intoxication. The patient started continue hydration with a close monitoring. Three hours later a significant narrowing of the QRS complex (150 ms) was observed, then over the following 24 h, the QRS almost completely normalized.
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