Identical twins with differing forms of ventricular pre-excitation
British Heart Journal
|February 1, 1978
Summary
Identical twins with identical ECGs showed different heart conditions. One twin had dangerous arrhythmias due to multiple pathways, while the other remained asymptomatic, highlighting varied clinical presentations of cardiac electrophysiology.
Area of Science:
- Cardiology
- Electrophysiology
- Genetics
Background:
- Identical twins can exhibit different clinical manifestations of genetic predispositions.
- Short PR interval and normal QRS complex on ECG can indicate underlying cardiac conduction abnormalities.
Purpose of the Study:
- To investigate the electrophysiological differences in identical twins with identical surface electrocardiograms.
- To characterize the presence and impact of atrioventricular nodal bypass tracts and accessory pathways.
Main Methods:
- Intracardiac electrophysiological studies were performed on both twins.
- Surface electrocardiograms were analyzed.
- Pharmacological intervention (amiodarone) was administered to one twin.
Main Results:
- One twin presented with symptomatic supraventricular and ventricular tachyarrhythmias, demonstrating both Lown-Ganong-Levine and Wolff-Parkinson-White syndromes.
- Electrophysiology confirmed an atrioventricular nodal bypass tract and an accessory atrioventricular pathway in the symptomatic twin.
- Amiodarone treatment resolved symptoms and altered electrophysiological findings in the symptomatic twin.
- The asymptomatic twin had an atrioventricular nodal bypass tract but no accessory pathways, and no inducible tachycardia.
Conclusions:
- Identical genetic makeup does not guarantee identical cardiac electrophysiological phenotypes or clinical outcomes.
- The presence of both atrioventricular nodal bypass tracts and accessory pathways can lead to severe, life-threatening arrhythmias.
- Pharmacological management can effectively control arrhythmias and modify electrophysiological characteristics in certain cardiac conduction disorders.
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