1 QRS: Wider is Better Variability in Electrical Activation - - PDF document

1 When to Consider LV lead Placement in the Non-LBBB IVCD Patient ?

Jag Singh MD DPhil FHRS

Associate Chief, Cardiology Division Professor of Medicine, Harvard Medical School Massachusetts General Hospital, Boston Deputy Editor, Journal Am Coll Cardiol: Clinical EP

Disclosures: Consultant: Biotronik, Boston Scientific, Impulse Dynamics, Liva Nova, Medtronic, Respicardia Inc, St. Jude Medical, theHeart.org, Research Grants: St. Jude Medical, Boston Scientific

Overview

CRT in the non-LBBB patient

• What is the real issue here?
• Is the concern secondary to

» patient substrate? » the LV lead strategy in this patient cohort?

• Is there a role for an individualized LV lead

implantation approach?

Levels of Electrical Dyssynchrony

• RV

lead

• LV lead

Singh JP and Gras D. Eur. Heart Journal 2012

• CRT Provides the Electrical Fix:
• Pacing wave-fronts from the RV and

LV lead

• Adjusting the A-V and V-V timings
• Inter-atrial

dyssynchrony Atrio-ventricular dyssynchrony Inter-ventricular dyssynchrony Intra-ventricular dyssynchrony Intramural dyssynchrony Truong QA, Hoffman U and Singh JP; Critical Pathways in Cardiology 2008

Conventional LV Placement Approach

Anatomical

• Suggested optimal

locations

• Postero-lateral wall
• Lateral wall
• Suggested mechanics
• Resets the electrical

activation sequence

• Reverses free wall

dyssynchrony

• The problem
• Inter and Intra-individual

variability

Singh JP et al JACC 2005

• 29

Auricchio et al. Am J Cardiol 1999 Butter C et al. Circulation 2001

2

Variability in Electrical Activation Sequence

Endocardial Maps

Piechl et al, PACE 2004:1105-12; Fantoni et al, JACC 2007,

• Considerable variability in electrical activation sequence
• Argues against the one-size fit all ‘anatomical lead positioning’

strategy

• May partially explain the variability in CRT response

LBBB RBBB RBBB + LAHB

QRS: Wider is Better

Across all patients

• Mechanistic point of view:
• Greater dyssynchrony
• Forgiving response to LV lead position
• The ESC guidelines had already endorsed 150 ms in 2010
• Influenced HFSA guideline committee’s approach in 2011

Sipahi I et al, Archives of Internal Medicine, 2011;171:1454-62

QRS Morphology

Determinants of CRT response

• LBBB improved across the board
• Non-LBBB variability in response
• Variability in activation sequence
• Conventional implant approach may not work
• Does that make it a sub-optimal population ?

Sipahi I et al. Am Heart Journal 2012;163: 260-267 Overall population

Segmental LV Lead Location (Apical vs. Non- Apical)

Longitudinal Axis

• Apical lead locations (via the coronary venous tree) are associated with

worse outcome

• Irrespective of QRS morphology and electrical activation sequence

Singh JP / Klein H et al, Circulation 2011 (MADIT-CRT Study)

3

LV Pacing Location & Response:

Thinking Beyond Anatomical Targeting Response To LV pacing

Depolarization wavefront RV-LV fusion Orientation

• f electrode

Myofibrillar pattern

Lead Location

Substrate Scar Surrounding Tissue Health Electro-mech. coupling Proximity to Purkinje

CRT an Electrical Fix

Targeting Electrical Delay, Clinical Outcome & Reverse Remodeling

• Ant
• Lat
• Post-Lat
• Activation Map
• Voltage Map

Ryu, P / Singh JP et al; JCE 2010

• 30

Gold MR, Green U, Singh JP et al.; European Heart Journal 2011 Singh JP et al. Mela T; Heart Rhythm , 2006;3:1285-92

Quadripolar lead:

Electrical Distancing within the Apical segment

• Quadripolar lead in the Apical region
• Variable electrical delay among electrodes
• Increased sensed electrical delay in the apical position=better outcome
• Needs to be tested prospectively

Distal 1

32.2 ms

M2

27.6 ms

M3

32.6 ms

Proximal 4

46.5 ms

Kandala, J / Singh JP et al J Cardiovasc Electrophysiology 2012

Electrical Targeting in non-LBBB

Clinical & Echocardiographic outcome

• Intra-procedural

LVLED in non-LBBB a determinant of

• utcome
• Graded remodeling

response

• Prospectively being

evaluated in the ENHANCE-CRT study

RBBB (18) IVCD (32) LBBB (71)

Kandala J / Singh JP et al. European Heart Journal 2013

4

Non-LBBB and CRT Response

• Underlying substrate different
• Different myopathic process
• Mechanical dyssynchrony

» Varied regions of dyssynchrony » Limited

• Co-existent co-morbidities

» CAD » COPD, etc.

• Temporal relationship of conductive disease to

cardiomyopathy?

Targeting Mechanical Dyssynchrony

STARTER Trial

Saba S / Gorcsan J et al Circulation HF 2013

Recognizing RV-LV interactions

It’s not all about the LV lead…..

A B1 C2 C1 B2

Singh JP et al, JICE, 2006 :17, 51-58 Kumar P / Singh JP et al. JICE 2012

Limited understanding RV lead position can impact acute hemodynamic response Individual variability for same LV lead position: clinically meaningful ? Septal CRT Study: No difference at the population level

LeClercq C et al. Europace 2015

Can Alternative approaches help?

• Shoulder Access to LV via Transseptal route
• Animal Study
• Complete CRT Implant via Shoulder approach with

LV lead implantation individualized to area of most delayed electrical activation

• Exner D, Auricchio A and Singh JP. Heart Rhythm 2012
• Singh JP and Gras D; EHJ 2011
• Endocardial approach

provides the needed individualization

• Best site is variable

5

ALSYNC: LV Endocardial approach

Potential for individualized approach in the non-LBBB patient

Morgan JM et al. European Heart Journal 2016 , 37: 2118-27

• Synchronized
• Targeted LV pacing
• Phased Array Ultrasound Transmitter

is Implanted in Intercostal Space

• Receiver Electrode (RE) is Implanted in

LV endocardium

• Converts ultrasound energy to

electrical pulse.

WISE Technology

(Investigational, ? individualized approach)

• SELECT LV Study*

–

Prospective, non randomized study with LV pacing pellet

–

35 patients who failed conventional CRT

–

Early data looks good

• SOLVE-CRT underway

* Reddy V et al. HRS 2015, * Singh JP, JACC: CEP August 2015

Take Home Points

• Levels of Electro-mechanical Dyssynchrony
• Anatomical targeting not specific enough

» Considerable inter-individual variability

• Selecting the non-LBBB patient

» Avoid the pure RBBB » Wider is better

• Individualizing the approach in non-LBBB

» Targeting electrical & mechanical delay » Ongoing trials (ENHANCE-CRT)

• Recognizing RV-LV lead interaction
• Future strategies may further individualization

» Endocardial approach

Thank You