| Wolff-Parkinson-White Syndrome (WPW) belongs to the so-called syndromes of pre-excitement. In these syndromes the electric stimulus of ventricular depolarization is transmitted from the atrium through an accessory pathway that bypasses the AV node.
As a result of these anomalies a characteristic electrocardiogram of the syndrome is produced:
- The PR interval is less than 0.12mm due to the rapidity of conduction through the accessory pathway that avoids the AV node.
- The QRS complex is wider because of the fusion of beats conducted by the accessory pathway, that depolarizes part of the ventricle and does it fibre to fibre, with the remainder of the ventricle depolarized on the other hand by the impulse transmitted through the AV node, as would occur in normal circumstances.
- In the first part of the QRS complex a so-called delta wave is observed, which is recorded by the part of myocardium depolarized by the accessory pathway, and which occurs more slowly since it is produced between the muscular fibers and not through the system of excito-conduction.
Autor:
Juan Ignacio
Pérez Calvo
Servicio de Medicina Interna
Hospital Clínico Universitario
Zaragoza
Translation: Kelly
Watt
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