The occurrence of atrial fibrillation (AF) in a patient with ventricular pre-excitation is a serious event, with a risk of sudden death due to an increased ventricular response and degeneration into ventricular fibrillation (VF).

Electrocardiographic Criteria

  • Absence of P waves
  • Irregularly irregular rhythm
  • QRS complexes of varying duration and morphology, > 120 ms in duration, due to transmission of the atrial impulse to the ventricular tissue through two pathways: the AV node and the accessory pathway
  • Rapid ventricular response, with rates usually > 200 bpm
  • The baseline ECG in sinus rhythm may show a short PR interval and a delta wave, supporting the diagnosis of ventricular pre-excitation

ECG in Pre-excited Atrial Fibrillation

Electrocardiogram with pre-excited atrial fibrillation

Pre-excited atrial fibrillation. Irregular rhythm with wide QRS complexes of varying morphology.

Electrocardiogram with ventricular pre-excitation

Ventricular pre-excitation. Previous tracing from the same case showing ventricular pre-excitation.

References

  1. Scheffer MK, De Marchi MFN, de Alencar Neto JN, Felicioni SP. Eletrocardiograma de A a Z. São Paulo: Manole, 2024.
  2. Brugada J, Katritsis DG, Arbelo E, Arribas F, et al. 2019 ESC Guidelines for themanagement of patients with supraventricular tachycardia. Eur Heart J. 2020;41(5):655–720.