Vanita Arora Associate Director & Head

Cardiac Electrophysiology lab & Arrhythmia Services Max Healthcare Superspeciality Services

New Delhi

ECG Assessment Alone Can Decide

CRT Candidature ?

Value of QRS in CRT

Before implant

– Patient selection

– Stimulation site selection ?

After implant

– Confirm biventricular capture

– Predict response

– Optimize programming

Identifying Responders In most studies, 20-30% of patients are non responders

Poor patient selection: there is not enough ventricular dyssynchrony – A wide QRS (ie > 120 ms) is necessary but not

sufficient to predict a positive response

– Nonviable myocardium

Failure to resynchronize – Electrode in non optimal position

– Inadequate A-V (o V-V) delay.

– Arrhythmias (rapid AF, frequent ventricular ectopy)

Relation between intrinsic QRS with and improvement with stimulation

Kass DA, et al. Circulation 1999;99:1567

Forest plot of parallel-arm randomized clinical trials

comparing outcomes by strata of baseline QRS duration

Bryant et al. J Electrocardiol 2013

Class I Indication by ACC/AHA 2008 Guidelines for CRT

Class III or Ambulatory Class IV HF on

optimal Medical therapy

QRS width120msec

LVEF <35%

Sinus Rhythm

• Associated AF- Class IIA • LV dysfunction (LVEF <35%) but NYHA class I or II and calling

for brady pacing independently, CRT could be considered - Class IIB

•QRS duration of > 120 ms

•Dominant S wave in V1

•Broad monophasic R wave in lateral leads (I, aVL, V5-V6)

•Absence of Q waves in lateral leads (I, V5-V6; small Q waves are still allowed

in aVL)

•Prolonged R wave peak time > 60ms in left precordial leads (V5-6)

Associated Features

•Appropriate discordance: the ST segments and T waves always go in the

opposite direction to the main vector of the QRS complex

•Poor R wave progression in the chest leads

•Left axis deviation

Conventional definition of LBBB

QRS Morphology in the Lateral Leads

The R wave in the lateral leads may be either:

•‘M’-shaped

•Notched

•Monophasic

•RS complex

QRS Morphology in V1

The QRS complex in V1 may be either:

•rS complex (small R wave, deep S wave)

•QS complex (deep Q/S wave with no preceding R wave)

Typical appearance of LBBB in V1 with rS complex

(tiny R wave, deep S wave) and appropriate discordance (ST elevation and upright T wave)

RBBB

•Broad QRS > 120 ms

•RSR’ pattern in V1-3 (‘M-shaped’ QRS complex)

•Wide, slurred S wave in the lateral leads (I, aVL, V5-6)

IVCD

RBBB - an rSR' complex in right-sided lead V1 - and wide terminal S

waves in left-sided leads I and V6

LBBB - upright, monophasic QRS in left-sided leads I and V6 - and a

predominantly negative QRS in right-sided lead V1

•The ECG appearance of IVCD is difficult to characterize

•This is because IVCD is often the end result of a number

of different pathophysiologic processes - rather than reflecting a discrete

defect in the conduction system (as usually occurs with RBBB or LBBB)

• Examples of conditions that may lead to IVCD include

myocardial infarction; cardiomyopathy with ventricular fibrosis;

chamber enlargement; and/or any combination of these

(with or without a component of bundle branch block)

•Thus, many patients with IVCD have at least some type of underlying

heart disease

Significance of QRS morphology in determining the

prevalence of mechanical dyssynchrony in heart

failure patients eligible for CRT

Haghjoo M et al. Europace 2008;10:566-571

Cumulative probability of heart failure (HF) event or death according to

treatment

CRT-D versus ICD only in patients with LBBB, non-LBBB…..

Zareba W et al. Circulation 2011;123:1061-1072

Bundle-Branch Block Morphology as a Predictor of Outcome

After CRTD in 15,000 Medicare Patients

Bilchick et al. Circulation 2010;122:2022

Strauss et al. Am J Cardiol 2011;107:927

Strauss et al. Am J Cardiol 2011;107:927

New “gold standard” for the definition of LBBB

High probability of improvement with CRT

2004

QRS 100 ms

Aug 5, 2012

QRS 121 ms

Sep 28, 2012

QRS 150 ms

Oct 9, 2012

QRS 172 ms

Oct 16, 2012

BiV

QRS 114 ms

Mascioli et al. PACE 2012; 35:927

ECG Criteria of True Left Bundle Branch Block: A Simple

Sign to Predict a Better Clinical Response to CRT

Patients with longer LV activation have better

outcome with CRT

Eitel et al. Europace 2012; 14:358

Jastrzebskiet al. Europace 2013; 15:258

Magnitude of benefit from CRT

Indications for CRT in patients in normal sinus rhythm

European Heart Journal

2013; 34: 2281–2329

Europace

2013; 15: 1070-1118

Highest

(responders)

Lowest

(non-responders)

Wider QRS, LBBB, females,

non-ischemic cardiomyopathy

Males, ischemic cardiomyopathy

Narrower QRS, non-LBBB

Cardiac Resynchronization Therapy in Patients With Systolic Heart Failure

CRT is indicated for patients who have left ventricular ejection fraction (LVEF) less than or equal to 35%, sinus rhythm, LBBB with a QRS duration greater than or equal to 150 ms, and NYHA class II, III, or ambulatory IV symptoms on GDMT. (Level of Evidence: A for NYHA class III/IV; Level of Evidence: B for NYHA class II).1 CRT can be useful for patients who have LVEF less than or equal to 35%, sinus rhythm, LBBB with a QRS duration 120 to 149 ms, and NYHA class II, III, or ambulatory IV symptoms on GDMT.2 CRT can be useful for patients who have LVEF less than or equal to 35%, sinus rhythm, a non-LBBB pattern with a QRS duration greater than or equal to 150 ms, and NYHA class III/ambulatory class IV symptoms on GDMT.2

I IIa IIb III

I I I IIa IIa IIa IIb IIb IIb III III III I I I IIa IIa IIa IIb IIb IIb III III III I I I IIa IIa IIa IIb IIb IIb III III III IIa IIa IIa IIb IIb IIb III III III

I I I IIa IIa IIa IIb IIb IIb III III III I I I IIa IIa IIa IIb IIb IIb III III III I I I IIa IIa IIa IIb IIb IIb III III III IIa IIa IIa IIb IIb IIb III III III

I I I IIa IIa IIa IIb IIb IIb III III III I I I IIa IIa IIa IIb IIb IIb III III III I I I IIa IIa IIa IIb IIb IIb III III III IIa IIa IIa IIb IIb IIb III III III

Recs

Modified

2012

1. Modified recommendation (specifying CRT in patients with LBBB of 150 ms; expanded to include those with NYHA class II symptoms).

2. New Recommendation

Recommendations Class Level

1) Patients with HF, wide QRS and reduced LVEF:

1a) should be considered in chronic HF patients, intrinsic QRS ≥120 ms and LVEF ≤35% who remain in NYHA functional class III and ambulatory IV despite adequate medical treatment (*), provided that a biventricular pacing as close to 100% as possible can be achieved.

IIa B

1b) AV junction ablation should be added in case of incomplete biventricular pacing. IIa B

2) Patients with uncontrolled heart rate who are candidates for AV junction ablation. CRT should be considered in patients with reduced LVEF who are candidates for AV junction ablation for rate control.

IIa B

Indication for CRT in patients with permanent AF

European Heart Journal

2013; 34: 2281–2329

Europace

2013; 15: 1070-1118

Recommendations Class Level

1) Upgrade from conventional PM or ICD is indicated in HF patients with LVEF <35% and high percentage of ventricular pacing who remain in NYHA class III and ambulatory IV despite adequate medical treatment.

I B

2) “De novo” implantation should be considered in HF patients, reduced EF and expected high percentage of ventricular pacing in order to decrease the risk of worsening HF.

IIa B

Upgraded or de novo CRT in patients with conventional pacemaker indications and HF

European Heart Journal

2013; 34: 2281–2329

Europace

2013; 15: 1070-1118

Clinical perspectives

• A strategy of initially conventional antibrady pacing with late upgrade in case of

worsening symptoms seems reasonable

• In the decision process physicians should take into account the excess

complication rate related to the more complex biventricular system, the shorter

longevity of CRT devices and the excess of costs.

• A 90 year old female presented with episodes of syncope from past 8 months

• She underwent Double Valve replacement (Aortic and Mitral) 1year ago for her severe aortic and mitral valve stenotic lesions

• Her 2DEcho showed LVEF 60% before the surgery • Postoperatively she had two episodes of acute left ventricular

failure requiring hospitalization • Her 2D Echo showed deterioration of LVEF to 30% and further

down to 20%.

Case Study

• She had recurrent episodes of pre-syncope and 2 episodes of syncope but no intervention was done for her, thinking she was too old for any further proceedure

• She also complained of easy fatiguability, weakness, lethargy, inability to do her day-to-day chores and breathlessness

• When she presented in Emergency with yet another episode of syncope, she was pale, fragile and stressed

57 yr old male Smoker Diabetic Admitted to emergency with chest discomfort, perspiration, difficulty in breathing from last 10-12 hours ECG – Ac. AWMI 2D Echo – EF 30% Family took another 2 hours to decide for CAG +/- PTCA LAD 100% occlusion was opened with placement of stent