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Phantom bypass tract

-from pathway to runway-

Patient presentation

  • 20 year old male

  • Aviation medical assessment
    -12 lead ECG showing pre-excitation (not currently available)

  • Asymptomatic 

  • EP study to assess the pathway
    -important to risk straitify the pathway for risk of SCD
    -1.4% of WPW patients will have SCD
    -EP assessment required to assess antegrade conduction >/=250ms

Baseline ECG/EGM

  • Normal AH and HV (70 and 40)

  • No evidence of pre-excitation 

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Retrograde incremental pacing

  • VA dissociation
     

  • No evidence of retrograde pathway conduction

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Antegrade pacing

  • Dual AV node physiology

  • AV wenckebach 360ms

  • AH jump 340ms

  • AVN ERP 260ms
    --(80ms tachycardia window)
     

  • No evidence of antegrade pathway conduction

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4mcg Isuprel infusion

Retrograde incremental pacing

  • Eccentric VA conduction (CS 1,2)

  • FIxed VA interval (non decremental)

  • Retrograde pathway ERP 350ms

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Retrograde paced extras

  • Eccentric VA conduction on the extra (CS 1,2)

  • retrograde pathway ERP 270ms

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Antegrade incremental pacing from CSd

  • Brief few beats seen with slight pre-excitation (HV 20ms) 

  • Antegrade accessory pathway 390ms

  • Delta wave on time with CS 3,4

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Atrial burst pacing

  • Repeatable atypical eccentric single echoes only

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Ablation considerations

  • Symptomatic

  • Prognostic AP

  • Risk assessment 
    -transeptal
    -proximity to AVN

  • Need for occupation / dream job

Australian ablation recommendations

Class I

  • Symptomatic AVRT or

  • Pre-excited AF
     

Class IIa

  • Asymptomatic antegrade AP conduction </= 250ms or

  • Asymptomatic with pre-excitation which precludes specific employment

References

•Aleong, R.G., Singh, S.M., Levinson, J.R & Milan, D.J. (2009). Catecholamine challenge unmasking high-risk features in the Wolff-Parkinson-White syndrome. Europace

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•Steinberg, C., Philippin, F., O’Hara, G. & Champagne, J. (2020). Orthodromic atrioventricular reentrant tachycardia using a concealed isoproterenol-sensitive accessory pathway.

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