AFib, Flutter, AVNRT

Includes some mapping tips and some info about the arrythmias

Slow pathway area

Triangle of kock

• usually between cs and tricupsid leaflet

AH Jump

Confirms dual nodal physiology (30 % ppl have it)

• Further testing determines if its AVNRT or AVRT

AH > 50 ms

What signals are you looking for AVNRT?

Junctionals

• A and Vs happening at same time → overlapping

Mechanism for AVRNT

Premature beat occurs → fast pathway is in RP but slow pathway with fast RP → signal travels down slow pathway and hits fast pathway at the end of its RP → causes reentrant loop

What are the 2 things necessary for a reentrant circuit?

Premature beat

Two pathways with different conduction speed and different RP

• Slow conduction has faster RP

• Fast conduction has slower RP

What type of signals are you looking for for the slow pathway?

Crunchy W signals

• Signals are crunchy and low amplitude because of the slow conduction in the slow pathway

What are you using as a reference pt for AVNRT?

BS

• System can’t discern A between V since they’re overlapped

• An A for every V

SVTs can start with CS ref but then switch to BS for AVNRT

What are you using as a reference pt for flutter?

CS

• Can see more of what is happening in the A (more As than V)

• Big A small V (far field V)

What are you looking out for during AVNRT ablation?

Fast junctionals (burning his) → heart block

• You want slow junctionals (400-600 ms)

PR elongation → heart is struggling to transmit signals from the A to the V (burn AV node)

See an A but no corresponding V (heart block = bad)

Catheter moves (don’t want to hurt his)

Electrogram of Flutter

Sawtooth

Concentric → probably right sided (CS9-10 down to CS1-2)

Multiple As for every V

I, II, avF need to be opposite in sign to V1 = right sided

• Make sure to look at same point on electrogram not the wave

Entrainment

Pace at a slightly faster speed than tach CL → measure from post pacing spike to next natural A signal in same pacing channel → ±30 ms of tach CL = pacing site in the circuit

LAT Histogram Flutter

Full cycle length should fill the histogram

• Ensure plenty of pts are taken

What anatomy is gathered for flutter?

RA, IVC, SVC, TVA, His

• Can mark annulus points when V signal is larger than A

Bi directional block Endpoint

Pace CS and measure signal on mapping cath that is lateral (near IVC)

• This interval should be longer than what it was at the beginning

• Also do this process from lateral to medial (MAP cath to cs cath)

Bipolar and Unipolar Map for AFIB

Bipolar: [0.1, 0.4]

Unipolar: [0, 1.08]

CL Range

For mapping in sinus can use 600-1000 (or whatever patient sinus CL is) for auto mapping

For flutter can use a range that is 0-5 ms from the patient’s flutter CL

Success criteria for AFIB

Exit block

• Pace in the PVs to ensure signal is not propagating into the A on cs electrogram

New voltage map

• PVs should should show as red

AFib map reference

In sinus:

• CS

AFIB: Can’t discern signals

• BS (more stable QRS)

Anatomy gathered in AFIB cases

LA, LAA, ESO, TS, PVs

WOI for arrythmias (to start)

Flutter: ½ the CL on each side

Everything else: to start

• CS ref: [-250,-50]

• BS ref: [15,200]

AFIB ECG/EGM

Squiggly chaos

Irregular intervals between the QRS

Coumadin Ridge

Between LAA and LUPV

Corina

Space between two veins