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Wide complex bigeminy: unusual presentation of an atriofascicular fiber
1Department of Pediatrics, Duke University Medical Center, Durham, North Carolina 27710.
Insights
Ventricular bigeminy in children is usually benign. However, this case highlights an atriofascicular fiber causing wide complex bigeminy, emphasizing its inclusion in differential diagnoses.
Area of Science:
- Pediatric Cardiology
- Electrophysiology
- Cardiac Arrhythmias
Background:
- Ventricular bigeminy in children is typically considered benign when no underlying heart disease is present.
- Wide complex arrhythmias necessitate careful evaluation to rule out serious pathology.
Observation:
- A pediatric patient presented with electrocardiographic findings of wide complex bigeminy and wide complex tachycardia.
- The presentation mimicked left bundle branch block morphology.
Findings:
- Electrophysiologic study revealed an atriofascicular fiber as the cause of the wide complex extrasystoles.
- Reentry within the atriofascicular fiber or its atrial insertion was identified as the mechanism.
- Retrograde conduction through the fiber was confirmed under specific testing conditions.
Implications:
- This case expands the differential diagnosis for wide complex bigeminy in children.
- Atriofascicular fibers should be considered in pediatric patients with wide complex arrhythmias, even without apparent structural heart disease.
Abstract:
Ventricular bigeminy in children is regarded as a benign arrhythmia in the absence of coexisting heart disease. We present the case of a patient with an atriofascicular fiber that electrocardiographically presented as wide complex bigeminy and wide complex tachycardia. At electrophysiologic study, the mechanism for the wide complex extrasystoles was reentry within the atriofascicular fiber or at its atrial insertion. Retrograde conduction within the fiber was also demonstrated under the influence of verapamil and ventricular extrastimulus testing. We conclude that conduction through an atriofascicular fiber should be included in the differential diagnosis of wide complex bigeminy having left bundle branch block morphology.