Fasciculoventricular Pathways

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Contents 1 Characteristics 2 Criteria 3 Differentiation of WPW-AS from FV pathways using V1 4 References

Characteristics

• Rarest form of preexcitation and does not give rise to reciprocating tachycardias
• EKG may mimic a manifest WPW with an anteroseptal pathway
• Fasciculoventricular Pathways have no VA conduction and permit only antegrade conduction like other Mahaim Tachycardias
• Patients with Fasciculoventricular Pathways can have coexisting SVTs

Criteria

1. Preexcitation exists with normal PR and AH intervals
2. Short and fixed HV interval
3. Atrial pacing produces AH prolongation due to AV nodal delay and does not affect the degree of preexcitation
4. His bundle stimulation produces preexcited QRS with short HV interval

Differentiation of WPW-AS from FV pathways using V1

1. PR interval > 110ms
2. Width of R wave less than 35ms
3. Amplitude of S wave less than 20mm
4. Flat or Negative Delta wave
5. Notching of the descending limb of the S wave

References

1. Oh, Et al., Electrocardiographic Characteristics of Fasciculoventricular Pathways. Pace 2005; 28:25-28