Value of the ECG Value of the ECG before and after before and after

cardiac cardiac resynchronization resynchronization

therapy therapy Sergio L. Pinski

Cleveland Clinic FloridaWeston, FL USA

Value of QRS in CRTValue of QRS in CRT

Before implant– Patient selection– Stimulation site selection ?

After implant– Confirm biventricular capture– Predict response – Optimize programming

Mechanisms of CRTMechanisms of CRT

Reduction in mechanical dyssynchrony of the LV

Reverse remodeling of the LV Optimization of left heart AV interval Reduction of mitral regurgitation Improvement in LV diastolic function

Identifying Responders 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

Sipahi et al. Arch Intern Med 2011; 171:1454

Impact of QRS Duration on Clinical Event Reduction With Cardiac Resynchronization Therapy: Meta-analysis of Randomized Controlled Trials

Random-effects meta-analyses of the weighted mean difference in baseline QRS duration between responders and

non-responders to CRT, usingremodeling definition of response

Bryant et al. J Electrocardiol 2013

Dupont et al. JACC 2012; 60:592

QRS duration and morphology in consecutive pts undergoing CRT at Cleveland Clinic Ohio

Significance of QRS morphology in determining the prevalence of mechanical dyssynchrony in heartfailure 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 (cardiac resynchronization therapy with defibrillator [CRT-D] versus implantable cardioverter

defibrillator [ICD] only) in patients with left bundle-branch block (LBBB), non-...

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

Relative risk of primary end point (heart failure event or death) by treatment (CRT-D versus ICD only) according to selected clinical characteristics in patients with or without LBBB

Zareba et al. Circulation 2011;123:1061

QRS Axis and the Benefit of CRT in Patients with Mildly Symptomatic Heart Failure in

MADIT‐CRT

Brenyo et al. J Cardiovasc Electrophysiol 2012

Figure 2

Sipahi et al. Amer Heart J 2012; 163:260 I:10.1016/j.ahj.2011.11.014 )

Bundle-Branch Block Morphology as a Predictor of Outcome After CRTD in 15,000 Medicare Patients

Bilchick et al. Circulation 2010;122:2022

Gold standard for LBBBGold standard for LBBB

No pathology correlate

Endocardial catheter mapping

Echo doppler studies showing delay in contraction of LV free wall vs. septum

Conventional definition of Conventional definition of LBBBLBBB1. QRS duration ≥ 120 ms in adults

2. Broad notched or slurred R wave in leads I, aVL, V5, and V6 and an occasional RS pattern in V5 and V6 attributed to displaced transition of QRS complex.

3. Absent q waves in leads I, V5, and V6, but in aVL, a narrow q wave may be present in the absence of myocardial pathology.

4. R peak time greater than 60 ms in leads V5 and V6 but normal in leads V1, V2, and V3, when small initial r waves can be discerned in the above leads.

5. ST and T waves usually opposite in direction to QRS.

6. Positive T wave in leads with upright QRS may be normal (positive concordance).

7. Depressed ST segment and/or negative T wave in leads with negative QRS (negative concordance) are abnormal

8. The appearance of LBBB may change the mean QRS axis in the frontal plane to the right, to the left, or to a superior, in some cases in a rate-dependent manner

Auricchio et al. Circulation 2004;109:1133

Timing of electrical activation (depolarization) wavefronts in normal conduction (A) and LBBB (B), shown in sagittal view.

Strauss D G et al. Circ Arrhythm Electrophysiol 2008;1:327-336

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

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

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

“True” LBBBnegative terminal deflection in V1 (QS or rS)> 140 ms in men, >130 ms in womenMid QRS notching

Combined effects of conduction defects and hypertrophy on QRS duration.

Strauss DG. J Electrocardiol 2012;45:635

New “gold standard” for New “gold standard” for the definition of LBBBthe 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

QRS morphology with QRS morphology with biventricular stimulationbiventricular stimulation

Location of RV electrode Location of wire in coronary wire Presence of fusion with intrinsic

conduction V-V timing (simultaneous versus

sequential). Latency, exit block with epicardial

pacing from coronary vein

Barold & Herweg. Cardiol J 2011; 18: 476

9-17-2001

9-19-2001

Barold & Herweg. Cardiol J 2011; 18: 476

LV

LVRVOT

RVOT

LV

Apex

LV

Mid Septum

ECG Diagnosis of Biventricular Pacing in Patients with Nonapical Right

Ventricular Leads

Jastrzebski et al. PACE 2012; 35:1199

LVLV

Apex Apex

LV

Apex

RVOT

Barold & Herweg. Cardiol J 2011; 18: 610

Latency with LV pacing

Barold & Herweg. Cardiol J 2011; 18: 610

Latency and slow conduction with LV pacing

Barold & Herweg. Cardiol J 2011; 18: 610

Programming V-V timing to circumvent LV latency

Herweg & Barold. PACE 2012;35:249

Lecoq et al. EHJ 2005;26:1094

Baseline and paced QRS duration in responders and nonresponders

The QRS Narrowing Index Predicts Reverse LV Remodelling Following CRT

Rickard et al. PACE 2011;34:604

QRS prolongation induced by CRT correlates with deterioration in LV

function

Rickard et al. Heart Rhythm 2012;9:1674

Jastrzebskiet al. Europace 2013; 15:258

Sweeney et al. Circulation. 121:626, 2010.

Analysis of Ventricular Activation Using Surface ECG to Predict LV Reverse Volumetric Remodeling During Cardiac Resynchronization Therapy.

Strauss et al. Circ Arrhythm Electrophysiol 2008;1:327

Sweeney et al. Circulation. 121:626, 2010.

Analysis of Ventricular Activation Using Surface ECG to Predict LV Reverse Volumetric Remodeling During Cardiac Resynchronization Therapy.

Predictors for Restoration of Normal LV Function in Response to CRT Measured at Time of Implant

Serdoz et al. Am J Cardiol 2011;108:75

Vaillant at al. JACC 2013

Resolution of Left Bundle Branch Block?Induced Cardiomyopathy by Cardiac Resynchronization Therapy

Optimization of the Interventricular Delay in CRT Using the QRS Width

Tamborero et al. Am J Cardiol 2009; 2009;104:1407