Cardiac Resynchronization Therapy:

Should Non-LBBB or Patients With

Atrial Fibrillation Receive CRT?

Michael R Gold, MD, PhD

Medical University of South Carolina

Charleston, SC

Disclosures: Consultant, Speaker Fees and Clinical Trials –

Boston Scientific, Medtronic, St Jude

Cardiac Resynchronization Therapy: Weight of Evidence

9,000 patients evaluated in randomized controlled trials of heart failure

Consistent improvement in quality of life, functional status, and exercise capacity

Strong evidence of changes in LV structure – ↓ LV volumes and dimensions

– LVEF

– ↓ Mitral regurgitation

Reduction in HF and all-cause morbidity and mortality

Pivotal RCTs of CRT

• NYHA II-IV

• LVEF < 35%

• QRS > 120-130 msec

• NRS (except RAFT)

• No study was restricted to LBBB or

even stratified randomization by BBB

or QRS duration

Subgroups Discouraged or

Prohibited from CRT by Updated

Guidelines

1. Non-LBBB

2. QRS < 150 msec

3. AF

RBBB in CRT Trials

Advanced HF

– MIRACLE

– CONTAK CD

– COMPANION

– CARE HF

Mild HF

– REVERSE

– MADIT-CRT

– RAFT

(28)

(33)

(162)

(35)

(82)

(228)

(161)

RBBB is not LBBB

Byrne MJ, Helm RH, et al. J Am Coll Cardiol 2007; 50: 1484-90.

Fantoni C, Kawabata M, Massaro R et al. J Cardiovasc Electrophysiol. 2005 Feb;16(2):112-9

Electrical Activation in RBBB and LBBB

Egoavil CA, Ho RT, Greenspon AJ, Pavri BB. Heart Rhythm. 2005 Jun;2(6):611-5.

COMPANION

Bristow, N Engl J Med. 2004;350:2140-50.

Heart Failure (HF) Event or Death by QRS Pattern in MADIT-

CRT Patients

LBBB Non-LBBB

RAFT

Tang. N Engl J Med. 2010 363:2385-2395.

12

REVERSE: Clinical Composite Subgroup Analysis

0.01 0.1 1 10

All Patients

Ischemic

Non-ischemic

CRT-P

CRT-D

NYHA Class I

NYHA Class II

Male

Female

0.26

0.90

0.46

0.52

Interaction

P-value

0.01 0.1 1 10

LBBB

RBBB

IVCD

Non-white

White

> 65 yrs

< 65 yrs0.75

0.60

0.01

Odds Ratio with 95% CI Odds Ratio with 95% CI

CRT ON

Better

CRT OFF

Better

CRT ON

Better

CRT OFF

Better

What is the QRS Morphology Hiding?

Can we identify patients or pacing sites with late mechanical or

electrical LV activation?

Hara H, et al. Eur Heart Journal. 2012.

Must be More Than Just RBBB

Hara H, et al. Eur Heart Journal. 2012.

Physiologic Guided Lead Positioning:

QLV Interval Measurement

Q-LV Interval to Predict Acute Response

R = 0.74

-5

0

5

10

15

20

25

30

35

40

0 50 100 150 200

Q-LV (ms)

%L

V+

dP

/dT

max

R

NR

Results: CRT Response By QLV Quartiles

Impact of QRS Duration

Cleland et al

Eur Heart J

2013

LVESV Response by Subgroup

Univariate Logistic Regression Results

RAFT: Primary Outcome

Mean F.U. :

25.2 + 18 months

673 pts 162 Permanent AF

114 pts

AF-abl

48 pts

Drugs + VRR

BVP % at 2 months

> 85% 85%

1. AVJ ablation and reverse remodelling

J Am Coll Cardiol 2006; 48 (4): 734-743

1) Significant EF increase both in SR and AF-abl No change for AF drugs

3) Similar LVESV reductions in SR and AF-abl

2) Functional capacity score increase both in SR and AF-abl

Meta Analysis of AVJ ablation for CRT.

1812 pts

Inadequate % BIV pacing

AF pts

AF pts

50% mortality if BIV pacing< 92%

25% pts BIV < 92%

Summary

CRT response rates are best in the presence

of sinus rhythm, LBBB and QRS > 150 msec

However, RCT included or studied other

groups of patients who show benefit, albeit

more variable

Late electrical mechanical activation helps

identify subjects with non-LBBB who respond

AV node ablation improves CRT response in

AFib