Int J Arrhythm.  2023 Jun;24(2):8. 10.1186/s42444-023-00091-5.

Accessory pathways in monozygotic twins with different clinical phenotypes: a case report

  • 1Pôle d’activité medico‑chirurgical cardio‑vasculaire, Nouvel Hôpital Civil, CHU de Strasbourg, 1, place de l’Hôpital, F‑67091 STRASBOURG cedex, France
  • 2INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine, FMTS, Strasbourg, France


The atrioventricular reentrant tachycardia (AVRT) is the most common tachycardia associated with accessory pathways (APs). Although sporadic Wolff-Parkinson-White (WPW) syndrome has been well-described, AP occurrence in identical twins with WPW syndrome remains rarely reported.
Case presentation
We report a case of 14-year-old monozygotic twin brothers referred for an electrophysiology (EP) study. Twin A presented with recurrent symptomatic narrow complex tachycardia after exercise, noted for 3 years. His 12-lead surface electrocardiogram (ECG) did not show ventricular pre-excitation. However, an orthodromic AVRT utilizing a concealed right posteroseptal AP was found and successfully ablated. AVRT did not recur 12 months after the procedure. Twin B was asymptomatic. During his medical examination for firefighter volunteerism, his 12-lead ECG showed a spontaneous ventricular pre-excitation. EP study revealed a short anterograde right midseptal AP, which was then successfully eliminated by catheter ablation. His 12-lead ECG showed no ventricular pre-excitation recurrence 12 months after the procedure.
These identical twin brothers had a right-side AP in almost the same place but showed completely different phenotypes. This case clearly illustrates the difficulty in understanding genetic contribution in the origin of atrioventricular APs. Environmental exposure could play a role in their clinical presentations and AP electrophysiological properties


Wolff-Parkinson-White syndrome; Accessory pathways; Atrioventricular reentrant tachycardia; Identical twins; Electrophysiology study; Catheter ablation
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