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Surface ECG Recognition /

Localization of Idiopathic Ventricular

Arrhythmias

Sanjay Dixit, M.D.

Professor, University of Pennsylvania School of Medicine

Director, Cardiac Electrophysiology, Philadelphia V.A.M.C.

45144

23885

808761

1199

233

1216

0

200

400

600

800

1000

1200

1400

ICM ARVC/D LVCM Idio RV Idio LV ILVT Pap VF trig Other

UPENN PVC / VT Ablations 1999-2018

(N = 4729)

40%

Outflow Tract and Basal Interventricular Septal Region:

Common sites of origin for idiopathic VAs

MV TV

PV

AV

- Heart model figure courtesy Samuel Asirvatham, MD

Anteroseptal Sup. RVOT

Aortic Cusp Region

Aorto-Mitral Continuity

Superior Basal Epicardium

Superior & lateral MA

Infero-basal septum

Infero-basal Crux

Outflow Tract Tachycardias: Typical ECG ManifestationsI

II

III

aVR

V6

aVL

aVF

V5

V4

V3

V2

V1

I

II

III

aVR

V6

aVL

aVF

V5

V4

V3

V2

V1

I

II

III

aVR

V6

aVL

aVF

V5

V4

V3

V2

V1

- Inferiorly

directed axis

- Left or Right

Bundle branch

Block pattern

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Influence of Cardiac Orientation on Unique ECG

Manifestations of Outflow Tract Tachycardias:

Morphology in lead V1 & Precordial Transition

RVOT

AV

MV

RC LC

NC

MV

AV

PV

aVR

RVFW

aVF

V1

V6

II

I

III

aVL

RV Septal RCC LV Septal LCC AMC

Position of ECG Leads V1 & V2:

Localization of Outflow Tract Tachycardia

- Anter, Dixit et al, Heart Rhythm 2012;9:697

Change in position:

Leads V1 and V2

Anterior RVOT Left-Right Cusp

Influence of Cardiac Orientation on Unique ECG

Manifestations of Outflow Tract Tachycardias:

Morphology in limb lead I

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Free Wall

Septum

3 2 13 2 1

PV

aVF

V2

V3

V4

V5

V6

II

I

III

aVR

aVL

V1

aVF

V2

V3

V4

V5

V6

II

I

III

aVR

aVL

V1

Free WallSeptum

12

3

12

3

Superior RVOT

- Dixit S et al, J Cardiovasc Electrophysiol. 2003;13(1):1-7

Position of ECG Lead I:

Localization of Outflow Tract Tachycardia

- Anter, Dixit et al, Heart Rhythm 2012;9:697

RVOT

Right Coronary Cusp

I

II

III

aVR

V6

aVL

aVF

V5

V4

V3

V2

V1

Left Coronary Cusp

I

II

III

aVR

V6

aVL

aVF

V5

V4

V3

V2

V1

21 3

Aortic Cusp Region The V2 Transition Ratio: A New ECG Criterion for

Distinguishing LV From RV Outflow Tachycardia Origin

I

II

III

R

L

F

I

II

III

R

L

F

V1

V2

V3

V4

V5

V6

V1

V2

V3

V4

V5

V6

Patient 1 Patient 2

Betensky … Gerstenfeld. JACC 2011;57:2255-62

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RVOT (n=18) LVOT (n=18)

TRANSITION RATIO =

(R/R+S)VT

(R/R+S)SR

0.29 1.16RS

RS

V1

V2

V3

V4

V5

V6

V1

V2

V3

V4

V5

V6

Results – V2 Transition Ratio

0.6

RCC

NCC

The V2 Transition Ratio: A New ECG Criterion for

Distinguishing LV From RV Outflow Tachycardia Origin

I

II

III

R

L

F

I

II

III

R

L

F

V1

V2

V3

V4

V5

V6

V1

V2

V3

V4

V5

V6

RVOT LVOT

Betensky … Gerstenfeld. JACC 2011;57:2255-62

Patient 1 Patient 2

Summary – ECG Criteria OT PVCs

LBB/inferior, precordial xition = V4 RVOT

LBB/inferior, precordial xition ≤ V2 Ao cusp

LBB/inferior, precordial xition = V3 V2 ratio

LBB/inferior, precordial xition ≥V5 *Consider ARVC

*Hoffmayer et al. JACC 2011;58:831-838.

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Activation in RVOTLBI PVCs with transition ≥ V4 Mapping in the Right CuspLBI PVC Pace MapDistance between earliest RVOT & Cusp location: 1cm

LV Summit: Anatomic Correlates

GCVAIV

LCC

NCCRCC

RVO

T

LVOT

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LV Summit VT: ECG Manifestations

I

II

III

aVR

V1

aVL

aVF

V6

I

II

III

aVR

V1

aVL

aVF

V6

I

II

III

aVR

V1

aVL

aVF

V6

LV Summit VT: ECG Manifestations

I

II

III

aVR

V1

aVL

aVF

V6

I

II

III

aVR

V1

aVL

aVF

V6

PERCUTANEOUS EPICARDIAL ABLATION OF VENTRICULAR ARRHYTHMIAS

ARISING FROM THE LEFT VENTRICULAR SUMMIT: OUTCOMES AND ECG

PREDICTORS OF SUCCESS

ECG Features associated

with successful epicardial

ablation of LV summit

VT:

1. Q wave ratio in leads

aVL/aVR >1.85.

2. R/S wave ratio in lead V1

>2.

3. Lack of initial “q” wave

in lead V1.

- Santangeli, Dixit et al, Circulation A&E, 2015;8:337

Localizing idiopathic ventricular arrhythmias

originating from the inferior basal septal region

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ECG features of VAs originating from the basal infero-septal LV

- Jackson L, Dixit S et al. J Am Coll Cardiol 2019;5:833-42

ECG features to differentiate VAs originating from

infero-basal LV endocardium Vs infero-basal crux region

- Jackson L, Dixit S et al. J Am Coll Cardiol 2019;5:833-42

ECG features of VAs originating from the slow pathway region

- Briceno D, Dixit S et al. Heart Rhythm Journal 2019;16:1421

MV TV

PV

AV

Inferior lead discordance in idiopathic ventricular arrhythmias

- Enriquez A et al. JCE 2017;28:1179-1186

SPR Region Mod. Band AL Pap Muscle

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ECG localization of VAs arising from the outflow

tract region and inferior basal septum: Summary

• Although these arrhythmias originate from narrow zones, they manifest distinct ECG morphologies.

• Careful analysis of 12 lead ECG can help in successful localization of the site of origin of these arrhythmias.

• To facilitate accurate ECG localization attention should be paid to lead placement, precordial transition patterns, patient’s body habitus and age.

Other Challenges to ECG

Localization of Outflow Tract

Tachycardias MV

TV

AV

AV

MVTV

PVA. B.

Influence of Age on Cardiac Orientation in

the Thoracic Cavity

- Maeda S, Lin D et al.

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- Timmermans, et al., Circulation 2003

RVOT VT Originating Above Pulmonic Valve

- Bala et al, Heart Rhythm 2010;7:312

VT Above The Right / Left Coronary Cusp Margin

VPD/VT from GCV/AIV – Accessible Area

I

IIIII

aVRaVL

aV

FV1

V6

QS in lead

1

Rs in V1

Santangeli, Marchlinski et al. Card EP Clinic. 2015 In Press

CS

Os

LCC

RCCNCC

AIV

NCC

RCC

LCC AIV

CS

Os

The Inaccessible AreaAblation from Adjacent Structures

LCC, LV Endo, RVOT

LCC

LV Endo

RVOT

W.A. McAlpine Collection-UCLA Cardiac Arrhythmia Center (with

permission)

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Ablation from LCC or Adjacent Endocardium of VT

Source Near the AIV (Earliest site/best PM) -16pts

Clue for Successful ablation – Anatomical Proximity

ECG clue - Q wave ratio aVL/aVR - <1.45

SuccessfulUnsuccessful

Anatomic Distance <13.5mm

Abularach et al Heart Rhythm. 2012;9:865-873

9pts7pts

Other clues:

• <5 ms difference in activation

• Output better

PM match

Ablation from Adjacent SitesClue for Successful ablation – Better PM Match with

High Output Pacing (Index of Anatomical Proximity)

Santangeli and Marchlinski. Heart Rhythm 2015. In Press

>20 mA ≤20 mA

AIV

LCC LV endo

RVOT

Targeting the inaccessible area of LV summit from

antero-septal RVOT

- Frankel et al, Circulation A&E, 2014;7:984

RAO LAO

- Frankel et al, Circulation A&E, 2014;7:984

Targeting the inaccessible area of LV summit from

antero-septal RVOT

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Septal - ParahisianAMCSup MASup Lat MALat MA

1 2 4 53

M V

AV

3

1

2 4

5

Inferior

Superior

Lateral Septal

200 msec

I

II

III

aVR

V6

aVL

aVF

V5

V4

V3

V2

V1

I

II

III

aVR

V6

aVL

aVF

V5

V4

V3

V2

V1

PA View

- Heart Rhythm, 2005

Is the outflow tract region arrhythmogenic by design?

• Developmentally the outflow tract (OFT) is derived from the second heart fieldwhich is molecularly and phenotypically different from the first heart field that gives rise to the left ventricle.

• The prenatal OFT remains undifferentiated and slowly conducting until it is incorporated into the RVOT; it is devoid of Tbx5 (which is required for expression of Cx40) and has no Cx43 expression.

• Remnants of the embryonic OFT phenotype and expression profile in the adult RVOT may determine its electrophysiologic characteristics and vulnerability to arrhythmias.

• There is heterogeneity over the apex to base axis of the heart and fate based mapping studies in the chicken heart show that cells located initially in the AV canal and OFT will become part of the base of ventricles.

Proximity of Outflow Tract Structures

RVOT & Cusps

LCC

RVOT

LCC

RVOT

Cusps & GCV

LCC

GCV

LCC

GCV

Basal LV & GCV

GCV

Basal

LV

GCV

Basal

LV

Epicardial ablation of LV Summit VT:

PENN experience

• Over 10 year period, 86 patients

with LV summit VT ablated.

• In the majority (n=63; 73%) the VT

was successfully ablated from

adjacent structures.

• In remaining 23 patients, epicardial

ablation was attempted in 14 and

was successful in only 5.

• Presence of ≥2 of the previous ECG

criteria predicted epicardial success

with 100% sensitivity and 72%

specificity.

- Santangeli, Dixit et al, Circulation A&E, 2015;8:337

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Outflow Tract Tachycardia: Unique

Features

• Mechanism: Triggered rhythm (DAD mediated)

• Focal site of origin

• Absence of structural heart disease

• Morphology of clinical arrhythmia can be mimicked by pace-mapping

• Pace mapping can be used to develop ECG criteria for localizing site(s) of origin of clinical tachycardias

• Electro-anatomic mapping facilitates accurate catheter localization and pace mapping

V A

I

II

III

aVR

V6

aVL

aVF

V5

V4

V3

V2

V1

CSPi

CSD

A B

LV

RVA

VT Originating From The Epicardium

Clinical PVC: LBBB, Inferior Axis, Small R wave in lead V1

QRS

Duration

(msec)

PDR in

Lead II

PDR in

Lead V3

PDR 0.55

in Lead II

or V3

R / S < 1

in

Lead V2

QS

morphology

in Lead I

EPI VT 19751 0.530.17* 0.510.126/7 (88%)* 6/7 (88%)* 7/7 (100%)*

ENDO VT 17421 0.460.09 0.370.08 0 0 0

* p < 0.05

ECG Characteristics of Epicardial

versus

Endocardial VT

- Bala, Dixit, et al. HRS 2006

Differentiating Epicardial from Endocardial location in the Anterior LV required

≥ 2 of the 3 pre-specified criteria

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E.C.G. Criteria for Distinguishing Epicardial from Endocardial VT

originating in the Superior / Basal Left Ventricle

• ECG recordings of epicardial VT in 7 pts (all right bundle branch block morphology) were compared to VT originating from corresponding endocardial sites in 6 pts

• ECGs were specifically analyzed for:

➢ 1) Peak deflection ratio (PDR): Ratio of time to 1st peak / nadir and QRS duration (QRSd) in leads II and V3

➢ 2) Lead V2: Ratio of R and S wave amplitude

➢ 3) Lead I: QRS morphology

- Bala, Dixit, et al. HRS 2006

Epicardial Sites

Endocardial Sites

Coronary SinusAIV

LCC

NCCRCC

R

V

O

T

LVOT

1st RF Lesion……………………………E.C.G. Criteria for Distinguishing Epicardial from Endocardial VT

originating in the Superior / Basal Left Ventricle

• ECG recordings of epicardial VT in 7 pts (all right bundle branch block morphology) were compared to VT originating from corresponding endocardial sites in 6 pts

• ECGs were specifically analyzed for:

➢ 1) Peak deflection ratio (PDR): Ratio of time to 1st peak / nadir and QRS duration (QRSd) in leads II and V3

➢ 2) Lead V2: Ratio of R and S wave amplitude

➢ 3) Lead I: QRS morphology

- Bala, Dixit, et al. HRS 2006

Epicardial Sites

Endocardial Sites

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1 2 3

T

V

PV

RV

1

2

33

2

1

Anterior

Posterior

S

e

p

t

u

m

Fre

e W

all

Typical Site(s) of Origin For RVOT Tachycardia

Site 1

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

Site 2

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

Site 3

I

II

III

aVRaVL

aVF

V1

V2

V3

V4

V5

V6

Site 1

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

aVR

Site 3

I

II

III

aVL

aVF

V1

V2

V3

V4

V5

V6

100 msec

1 mV

Localizing Basal LV VT

M VAV

Sup Septum

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

I

AMC

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

Superior MA

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

Sup-Lateral MA

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

Parahisian

107

59

121

232217

56

366

0

50

100

150

200

250

300

350

400

VT CAD VT

RVCM*

VT

LVCM

RVOT

VT

LVOT

VT

Idio LV

VT

Other

VT

UPENN VT Ablations 1999- 2008(1158 VT ablation procedures ) Distribution of Idiopathic VT:

PENN Experience

1999 – 2003

(N = 431)

2004 – 2008

(N = 705)

P Value

RVOT 103 (24%) 115 (16%) P < 0.01

LVOT 24 (6%) 95 (14%) P < 0.001

LV & RVOT 4 (1%) 10 (1%) P = NS

Fascicular VT 18 (4%) 30 (4%) P = NS

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- Circulation 2006;113:1169 - Circulation 2006;113:1169

RVOT

Cusps

Basal

LV

VT PM

- Betensky, Gerstenfeld, et al, JACC 2011;57:2255

RVOT LVOT

Distinguishing RVOT from LVOT

Tachycardia: Lead V2 Transition Ratio