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Triple threat

-rhythm shifts & diagnostic rifts-

Patient presentation

  • 21 year old male

  • recurrent palpitations

  • documented tachycardia on ECG
    -broad complex, regular tachycardia

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Differential diagnosis

  • SVT with aberrancy

  • Ventricular tachycardia

  • Antidromic AVRT

Baseline ECG/EGM

  • AH: 82

  • HV: -12

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Retrograde incremental pacing

  • Midline, decremental retrograde atrial activation (earliest CS 9,10)

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  • Change in atrial activation pattern at faster rates - eccentric (CS 1,2)

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Atrial incremental pacing

  • Increase in pre-excitation with faster rates

  • Atrial latency noted

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Antegrade paced extras

  • Increase in pre-excitation

  • Atrial latency on extra

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Tachycardia 1 Induction

  • Ventricular paced extras

  • Some variation in 1st few atrial beats prior to tachycardia settling
    TCL 300, VA 94
    Eccentric VA conduction (CS 5,6 earliest)

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Tachycardia 1: HSVPB

  • No change in A-A interval

  • Nothing ruled out

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Tachycardia 1: Ventrainment - 330ms

  • Terminated arrhythmia - unable to observe post entrainment response

  • <1 beat to entain the atrium when venticle is fully captured.

  • Change in atrial activation pattern with entrainment (bystander pathway - pattern 3)

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Tachycardia 1: V entrainment 2nd attempt- 270ms

  • VAHV response

  • PPI-TCL = 410-296 = 114 (borderline numbers- but not septal pathway)
    Stim A - VA = 94 (borderline numbers- but not septal pathway)

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Tachycardia 1 Diagnosis

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Tachycardia 2: induction

  • Induced with atrial sensed doubles on Isuprel
    TCL 280 VA 80
    Eccentric VA conduction (CS 1,2)

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Tachycardia 2: V entrainment 270ms

  • change in atrial activation pattern during entrainment
    -likely bystander

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Tachycardia 2: HSVPB

  • change in atrial activation pattern with atrial advancement 
    -tachycardia 1 bypass tract acting as bystander for tachycardia 2

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Tachycardia 2: ablation

  • Mapped to postero-lateral LA

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  • Change in atrial activation pattern during ablation to atrial pattern 3
    (tachycardia 2 terminate)

Tachycardia 2: post ablation

  • loss of pre-excitation

  • no inducible tachycardia 1 or 2

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Tachycardia 3: ablation

  • CS 9,10 activation pattern earliest
    (acted as bystander to previous tachycardia with entrainment on 1st beat - consistent with pathway)

  • Mapped to antero-septal RA - ablated with cryo

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Tachycardia 3: post ablation

  • VA conduction midline & decremental 
    VA wenckebach 600ms

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  • No pre-excitations

  • AV nodal wenckebach 280ms

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  • Atrial sensed extras
    -    echoes (mechanisms unclear)
    -no inducible tachycardia (very easily inducible (each tachycardia) prior to ablaion)

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Post op ECG

  • ST / T wave changes on ECG

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T wave memory

  • T wave abnormalities occur in patients with WPW due to abnormal ventricular activation and therefore repolarisation to the additional bypass tract(s).

  • After ablation of a bypass tract, the abnormal T wave may remain (memory), but tends to improve/disappear within weeks to months.

  • Persistent T wave changes are often mistaken as myocardial ischemia.

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References

  • Helguera, M. E. et al., (1994). Memory T waves after radiofrequency catheter ablation of accessory atrioventricular connections in wolff-parkinson-white syndrome. Journal of Electrocardiology, 27(3), 243-249

  • Kanjwal, K. et al., (2021). What Is the Response Seen During Para-Hisian Pacing? Journal of innovations in cardiac rhythm management, 12(9), 4677-4680.

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