Atypical bypass tracts: can they be recognized during sinus rhythm?

Europace. 2019 Feb 1;21(2):208-218. doi: 10.1093/europace/euy079.

Abstract

Atypical bypass tracts or variants of ventricular pre-excitation are rare anatomic structures often with rate-dependent slowing in conduction, called decremental conduction. During sinus rhythm, electrocardiographic recognition of those structures may be difficult because unlike in the Wolff-Parkinson-White syndrome where usually overt ventricular pre-excitation is present, the electrocardiogram (ECG) often shows a subtle pre-excitation pattern because of less contribution to ventricular activation over the slow and decrementally conducting bypass. Following the structure described by Ivan Mahaim and Benatt corresponding to a fasciculoventricular pathway, several other new variants of ventricular pre-excitation were reported. In this review, we aim to discuss the electrocardiographic pattern of the different subtypes of variants of ventricular pre-excitation, including the atriofascicular pathway, long and short decrementally conducting atrioventricular pathways, fasciculoventricular pathway, the atrio-Hisian bypass tract, and nodoventricular and nodofascicular fibres. Emphasis will be on the ECG findings during sinus rhythm.

Publication types

  • Review

MeSH terms

  • Accessory Atrioventricular Bundle*
  • Action Potentials
  • Adenosine / administration & dosage
  • Animals
  • Electrocardiography*
  • Heart Conduction System / physiopathology*
  • Heart Rate*
  • Humans
  • Pre-Excitation Syndromes / diagnosis*
  • Pre-Excitation Syndromes / physiopathology
  • Pre-Excitation, Mahaim-Type / diagnosis*
  • Pre-Excitation, Mahaim-Type / physiopathology
  • Predictive Value of Tests

Substances

  • Adenosine