EP Rounds

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27-03-2020

Raja Selvaraj, JIPMER

Case 1 - Accessory pathway ablation

  • 47 year old male
  • Recurrent palpitations with documented SVT
  • Two failed previous ablations

Marks et al. JCE 2020. DOI: 10.1111/jce.14434

Sinus rhythm - Map catheter in anterior CS os

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Fractionated signal

  • Fractionated A from previous ablation
  • AP potential
  • His signal

Tachycardia induction with burst atrial pacing

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Findings

  • Decremental conduction from A to signal
  • Tachycardia induction associated with block to signal
  • During tachycardia, signal seen after V

Mapping

  • Earliest A during tachycardia - high, posterior CS os
  • AP potential more anterior and inferior
  • Where to ablate ?

Learning points

  • Diagnostic catheter used for mapping
  • Ablation at AP potential better than earliest A
  • Difficult PSAP - consider epicardial AP, map within CS

Case 2 - Parahisian pacing

  • 21 year old female
  • Narrow QRS tachycardia
  • Terminated with adenosine

Kara et al. JCE 2020. DOI: 10.1111/jce.14334

Parahisian pacing - What is the interpretation ?

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What is the interpretation ?

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Recap

  • Transition from RV to RV+HB capture resulted in VA block
  • Long-short HH cycle - HA block anticipated
  • HA block = VA block. Indicates nodal conduction

Learning points

  • Parahisian - complex to interpret, but provides wealth of information
  • VA block associated with short HH cycle suggests nodal conduction

Case 3 - Narrow QRS tachycardia

  • 76 year old woman
  • No structural heart disease
  • Narrow QRS tachycardia

Wakamatsu et al. JCE 2019. DOI: 10.1111/jce.14131

ECG - What is the differential diagnosis ?

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ECG

  • Regular narrow QRS tachycardia
  • 150 bpm
  • V > A
  • Possible 4:3 VA
  • P waves inverted in inferior leads

Narrow QRS tachycardia with V > A

  • Ventricular tachycardia
  • AVNRT
  • Junctional tachycardia
    • Automatic
    • Intra-His reentry
  • Concealed nodoventricular AP with orthodromic AVRT

EP study

  • CL / AH / HV - 634 / 90 / 46 ms
  • RV pacing - earliest activation at prox CS, VAWB 480 ms
  • RV extras - central, decremental
  • Atrial extras - Two AH jumps - 320 ms and 290 ms
  • Tachycardia induced by atrial burst pacing

Intracardiac - Tachycardia

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  • Normal HV, not VT
  • No split His - Not intra His reentry
  • Change in A activation due to fusion with sinus

SVT with V > A, central A activation.

What now ?

  • 1:1 conduction needed for pacing maneuvers
  • Isoprenaline resulted in 1:1 VA

Ventricular extra during tachycardia

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Ventricular overdrive pacing

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RV Pacing at 430 ms, 420 ms and during sinus

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Recap

  • His refractory PVC advances next His and advances subsequent A
  • RVOP - VVA response (pseudo VAV), PPI-TCL 60 ms
  • VA time longer than TCL
  • Manifest fusion during entrainment from RV
  • Diagnosis ?

Interpretation

  • PPI-TCL and fusion consistent with ORT
  • ORT with VA block - infranodal AP
  • Fusion during entrainment - nodoventricular AP, not nodofascicular
  • Very long VA time - bystander slow pathway

Schematic

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Management

  • No discrete potential identified to ablate AP
  • Anatomical slow pathway ablation done
  • No further tachycardia

Learning points

  • DD for NQRST with V > A
  • Getting 1:1 VA with isoprenaline is critical
  • Proper measurement with PVCs / RVOP is important
  • Slow pathway ablation for NV AP - because of insertion into SP