EP Rounds

27-03-2020

Raja Selvaraj, JIPMER

Case 1 - Accessory pathway ablation

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

Sinus rhythm - Map catheter in anterior CS os

Fractionated signal

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

Tachycardia induction with burst atrial pacing

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

Parahisian pacing - What is the interpretation ?

What is the interpretation ?

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

ECG - What is the differential diagnosis ?

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

• 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

Ventricular overdrive pacing

RV Pacing at 430 ms, 420 ms and during sinus

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

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