References and Library

Table of Contents

Part 1: Webcasts and presentations

Part 2: Teaching course on CRT

Part 3: Clinical Cases

Part 4: References and Library

Part 5: Frequently Asked Questions

Part 6: Pathophysiology of electromechanical dyssynchrony

Part 7: Webinars

References from the presentation: imaging in CRT

1. Stephansen C, Sommer A, Kronborg MB, Jensen JM, Bouchelouche K, Nielsen JC. Electrically guided versus imaging-guided implant of the left ventricular lead in cardiac resynchronization therapy: a study protocol for a double-blinded randomized controlled clinical trial (ElectroCRT). Trials 2018;19:600.
2. Cikes M, Sanchez-Martinez S, Claggett B, et al. Machine learning-based phenogrouping in heart failure to identify responders to cardiac resynchronization therapy. Eur J Heart Fail 2018.
3. Gorcsan J, 3rd, Anderson CP, Tayal B, et al. Systolic Stretch Characterizes the Electromechanical Substrate Responsive to Cardiac Resynchronization Therapy. JACC Cardiovasc Imaging 2018.
4. Zweerink A, van Everdingen WM, Nijveldt R, et al. Strain imaging to predict response to cardiac resynchronization therapy: a systematic comparison of strain parameters using multiple imaging techniques. ESC Heart Fail 2018.
5. Marwick TH, Poole J. Cardiac Resynchronization Therapy in the Absence of LV Mechanical Dyssynchrony: Primum Non Nocere. J Am Coll Cardiol 2018;71:1334-6.
6. Tayal B, Gorcsan J, 3rd, Bax JJ, et al. Cardiac Resynchronization Therapy in Patients With Heart Failure and Narrow QRS Complexes. J Am Coll Cardiol 2018;71:1325-33.
7. De Pooter J, Kamoen V, El Haddad M, et al. Gender differences in electro-mechanical characteristics of left bundle branch block: Potential implications for selection and response of cardiac resynchronization therapy. Int J Cardiol 2018;257:84-91.
8. Gold MR, Yu Y, Wold N, Day JD. The role of interventricular conduction delay to predict clinical response with cardiac resynchronization therapy. Heart Rhythm 2017;14:1748-55.
9. Stankovic I, Belmans A, Prinz C, et al. The association of volumetric response and long-term survival after cardiac resynchronization therapy. Eur Heart J Cardiovasc Imaging 2017;18:1109-17.
10. Birnie D, Hudnall H, Lemke B, et al. Continuous optimization of cardiac resynchronization therapy reduces atrial fibrillation in heart failure patients: Results of the Adaptive Cardiac Resynchronization Therapy Trial. Heart Rhythm 2017;14:1820-5.
11. Mele D, Nardozza M, Malagu M, et al. Left Ventricular Lead Position Guided by Parametric Strain Echocardiography Improves Response to Cardiac Resynchronization Therapy. J Am Soc Echocardiogr 2017;30:1001-11.
12. van Everdingen WM, Walmsley J, Cramer MJ, et al. Echocardiographic Prediction of Cardiac Resynchronization Therapy Response Requires Analysis of Both Mechanical Dyssynchrony and Right Ventricular Function: A Combined Analysis of Patient Data and Computer Simulations. J Am Soc Echocardiogr 2017;30:1012-20 e2.
13. Donal E, Hernandez A, Hubert A, Galli E, Bernard A. Imaging in the field of cardiac resynchronization therapy: a real additive value? Acta Cardiol 2017;72:237-9.
14. Fournet M, Bernard A, Marechaux S, et al. Pilot study using 3D-longitudinal strain computation in a multi-parametric approach for best selecting responders to cardiac resynchronization therapy. Cardiovasc Ultrasound 2017;15:15.
15. Bernard A, Menet A, Marechaux S, et al. Predicting Clinical and Echocardiographic Response After Cardiac Resynchronization Therapy With a Score Combining Clinical, Electrocardiographic, and Echocardiographic Parameters. Am J Cardiol 2017;119:1797-802.
16. Donal E, Delgado V, Magne J, et al. Rational and design of EuroCRT: an international observational study on multi-modality imaging and cardiac resynchronization therapy. Eur Heart J Cardiovasc Imaging 2017;18:1120-7.
17. Menet A, Bernard A, Tribouilloy C, et al. Clinical significance of septal deformation patterns in heart failure patients receiving cardiac resynchronization therapy. Eur Heart J Cardiovasc Imaging 2017;18:1388-97.
18. Cvijic M, Zizek D, Antolic B, Zupan I. Time Course of Electrical Remodeling of Native Conduction After Cardiac Resynchronization Therapy and Its Impact on Clinical Outcome. J Card Fail 2017;23:257-61.
19. Gorcsan J, 3rd, Tayal B. Newer Echocardiographic Techniques in Cardiac Resynchronization Therapy. Heart Fail Clin 2017;13:53-62.
20. Cobb DB, Gold MR. The Role of Atrioventricular and Interventricular Optimization for Cardiac Resynchronization Therapy. Heart Fail Clin 2017;13:209-23.
21. Behar JM, Claridge S, Jackson T, et al. The role of multi modality imaging in selecting patients and guiding lead placement for the delivery of cardiac resynchronization therapy. Expert Rev Cardiovasc Ther 2017;15:93-107.
22. Marechaux S, Menet A, Guyomar Y, et al. Role of echocardiography before cardiac resynchronization therapy: new advances and current developments. Echocardiography 2016;33:1745-52.
23. Daubert C, Behar N, Martins RP, Mabo P, Leclercq C. Avoiding non-responders to cardiac resynchronization therapy: a practical guide. Eur Heart J 2017;38:1463-72.
24. Delgado-Montero A, Tayal B, Goda A, et al. Additive Prognostic Value of Echocardiographic Global Longitudinal and Global Circumferential Strain to Electrocardiographic Criteria in Patients With Heart Failure Undergoing Cardiac Resynchronization Therapy. Circ Cardiovasc Imaging 2016;9.
25. Gorcsan J, 3rd, Tayal B. Newer Echocardiographic Techniques in Cardiac Resynchronization Therapy. Card Electrophysiol Clin 2015;7:609-18.
26. Stankovic I, Prinz C, Ciarka A, et al. Relationship of visually assessed apical rocking and septal flash to response and long-term survival following cardiac resynchronization therapy (PREDICT-CRT). Eur Heart J Cardiovasc Imaging 2016;17:262-9.
27. Delgado V, Bax JJ. Cardiac Simulation to Personalize Cardiac Resynchronization Therapy. Circ Cardiovasc Imaging 2015;8:e003985.
28. Lumens J, Tayal B, Walmsley J, et al. Differentiating Electromechanical From Non-Electrical Substrates of Mechanical Discoordination to Identify Responders to Cardiac Resynchronization Therapy. Circ Cardiovasc Imaging 2015;8:e003744.
29. Risum N, Kisslo J, Wagner G. Cardiac resynchronization therapy: Identifying an activation delay by regional strain analysis. J Electrocardiol 2015;48:779-82.
30. Risum N, Tayal B, Hansen TF, et al. Identification of Typical Left Bundle Branch Block Contraction by Strain Echocardiography Is Additive to Electrocardiography in Prediction of Long-Term Outcome After Cardiac Resynchronization Therapy. J Am Coll Cardiol 2015;66:631-41.
31. Feneon D, Behaghel A, Bernard A, et al. Left atrial function, a new predictor of response to cardiac resynchronization therapy? Heart Rhythm 2015;12:1800-6.
32. Boe E, Smiseth OA, Storsten P, et al. Left ventricular end-systolic volume is a more sensitive marker of acute response to cardiac resynchronization therapy than contractility indices: insights from an experimental study. Europace 2018.
33. Galli E, Leclercq C, Fournet M, et al. Value of Myocardial Work Estimation in the Prediction of Response to Cardiac Resynchronization Therapy. J Am Soc Echocardiogr 2018;31:220-30.
34. Haugaa KH, Edvardsen T, Smiseth OA. Mechanical dyssynchrony-resurrected as a flashing and rocking parameter to predict prognosis after cardiac resynchronization therapy. Eur Heart J Cardiovasc Imaging 2017;18:1118-9.
35. Vecera J, Penicka M, Eriksen M, et al. Wasted septal work in left ventricular dyssynchrony: a novel principle to predict response to cardiac resynchronization therapy. Eur Heart J Cardiovasc Imaging 2016;17:624-32.
36. Donal E, Galli E, Cosyns B. Twenty years after starting cardiac resynchronization therapy, do we understand the electromechanical coupling? Eur Heart J Cardiovasc Imaging 2018.
37. Hasselberg NE, Haugaa KH, Bernard A, et al. Left ventricular markers of mortality and ventricular arrhythmias in heart failure patients with cardiac resynchronization therapy. Eur Heart J Cardiovasc Imaging 2016;17:343-50.

Key reference library

Pathophysiology of mechanical dyssynchrony

Left bundle branch block induces ventricular remodelling and functional septal hypoperfusion

Vernooy K , 2004, Eur Heart J

The authors studied wether isolated left bundle branch block (induced in eight dogs) causes left ventricular dilatation, hypertrophy, and septal perfusion defects. In conclusion, the asynchronous ventricular activation during LBBB leads to redistribution of circumferential shortening and myocardial blood flow and, in the long run, LV remodelling.

Apex-to-base dispersion in regional timing of left ventricular shortening and lengthening

Sengupta PP, Khandheria BK, Korinek J, Wang J, Jahangir A, Seward JB, Belohlavek M , 2006, J Am Coll Cardiol

With experimental methods and sonomicrometry, this study demonstrated that there is a physiological dyssynchrony between the apex and the base and according to fiber orientation.

Concordance between mechanical and electrical dyssynchrony in heart failure patients: a function of the underlying cardiomyopathy?

Tournoux F, Donal E, Leclercq C, De Place C, Crocq C, Solnon A, Cohen- Solal A, Mabo P, Daubert J-C. , 2007, Journal of Cardiovascular Electrophysiology

The authors concluded that the concordance between electrical dyssynchrony assessed by QRS duration and mechanical dyssynchrony assessed by myocardial strain is dependent upon the underlying cardiomyopathy, and that no concordance was found in ischaemic disease.

Mechano-energetics of the asynchronous and resynchronized heart

Prinzen FW, Vernooy K, Deboeck BWL, Delhaas T , 2010, Heart Fail Rev

This review explains how abnormal electrical activation of the ventricles creates major abnormalities in cardiac mechanics and how cardiac resynchronisation therapy improves mechano-energetics of the previously asynchronous heart in various ways.

Mechanisms of abnormal systolic motion of the interventricular septum during left bundle-branch block

Gjesdal O, Remme EW, Opdahl A, Skulstad H, Russell K, Kongsgaard E, Edvardsen T, Smiseth OA , 2011, Circ Cardiovasc Imaging

The authors studied the mechanism of the abnormal leftward motion of the interventricular septum during the pre-ejection phase to determine the part of active and passive motion.

Septal Deformation Patterns Delineate Mechanical Dyssynchrony and Regional Differences in Contractility: Analysis of Patient Data Using a Computer Model

Leenders GE, Lumens J, Cramer MJ, De Boeck BWL, Doevendans PA, Delhaas T, Prinzen FW , 2012, Circ Heart Fail

The authors investigated the effects of dyssynchronous activation and differences in septal and left ventricular free wall contractility on septal deformation pattern, with the use of the CircAdapt computer model of the human heart and circulation.

Ventricular resynchronization is the principle mechanism of benefit with cardiac resynchronization therapy

Gorcsan J, Yu CM, Sanderson JE, 2012, Heart Fail Rev

Review about dyssynchrony and resynchronisation as best measure of CRT response.

The role of echocardiography in quantification of left ventricular dyssynchrony: state of the art and future directions

Smiseth OA, Russell K, Skulstad H, 2012, Eur Heart J Cardiovasc Imaging

This review article discusses how echocardiography can be used to quantify myocardial dyssynchrony in CRT candidates. The article emphasises the importance of differenciating between electrical and non-electrical aetiologies of dyssynchrony. The authors propose to use time of active force generation to identify electrical dyssynchrony. They discuss a non-invasive method to measure segmental pressure-strain loops to quantify the impact of dyssynchrony on distribution of myocardial work.

Prediction of LV reverse remodeling / prediction of CRT-response

Echocardiographic modeling of cardiac dyssynchrony before and during multisite stimulation: a prospective study

Atrio-ventricular dyssynchrony

Cazeau S, Bordachar P, Jauvert G, Lazarus A, Alonso C, Vandrell MC, Mugica J, Ritter P , 2003, Pacing Clin Electrophysiol

This pilot study explored the value of an echocardiographic model to identify cardiac electromechanical dyssynchrony parameters in candidates for CRT, and their potential correction after implantation. It describes clearly the principle of atrio-ventricular asynchrony.

Cardiac resynchronization therapy tailored by echocardiographic evaluation of ventricular asynchrony

Intraventricular dyssynchrony : M mode

Pitzalis MV, Iacoviello M, Romito R, Massari F, Rizzon B, Luzzi G, Guida P, Andriani A, Mastropasqua F, Rizzon P , 2002, J Am Coll Cardiol

The septal-to-posterior wall motion delay (SPWMD), quantified by M-mode, was evaluated in 20 patients and appeared to be a strong predictor of reverse remodelling after CRT.

Usefulness of ventricular dyssynchrony measured using M-mode echocardiography to predict response to resynchronization therapy

Intraventricular dyssynchrony : M mode

Díaz-Infante E, Sitges M, Vidal B, Mont L, Delgado V, Marigliano A, Macias A, Tolosana JM, Tamborero D, Azqueta M, Roig E, Paré C, Brugada J , 2007, Am J Cardiol

This study demonstrated that SPWMD was not a good predictor of response to CRT. At six-month follow-up, baseline SPWMD was not associated with clinical response, New York Heart Association functional class, distance walked in six minutes, LV reverse remodelling, or neurohormonal activation. SPWMD >130 ms was also not a predictor.

Left ventricular dyssynchrony predicts response and prognosis after cardiac resynchronization therapy

Bax JJ, Bleeker GB, Marwick TH, Molhoek SG, Boersma E, Steendijk P, van der Wall EE, Schalij MJ , 2005, J Am Coll Cardiol

This study demonstrated that an optimal cutoff value of 65 ms for LV dyssynchrony yielded a sensitivity and specificity of 80% to predict clinical improvement and of 92% to predict LV reverse remodeling.

Tissue Doppler imaging is superior to strain rate imaging and postsystolic shortening on the prediction of reverse remodeling in both ischemic and nonischemic heart failure after cardiac resynchronization therapy

Tissue Doppler imaging

Yu CM1, Fung JW, Zhang Q, Chan CK, Chan YS, Lin H, Kum LC, Kong SL, Zhang Y, Sanderson JE., 2004, Circulation

This study compared the relative predictive values of tissue Doppler imaging and strain rate imaging parameters for LV reverse remodelling in patients who received CRT. SD of time to peak myordial contraction by TDI was the most powerful predictor of LV reverse remodelling and was consistently useful for ischaemic and nonischaemic heart failure.

Predictors of left ventricular reverse remodeling after cardiac resynchronization therapy for heart failure secondary to idiopathic dilated or ischemic cardiomyopathy

Tissue Doppler Imaging

Yu CM, Fung WH, Lin H, Zhang Q, Sanderson JE, Lau CP, 2003, Circulation

In 30 heart failure patients systolic dyssynchrony assessed as SD of time to peak strain by TDI (dyssynchrony index; ""Yu index)), was assessed before and three months after CRT implantation. Both baseline dyssynchrony index and improvement of dyssynchrony index were strong markers of reverse remodelling.

Results of the Predictors of Response to CRT (PROSPECT) trial

Tissue Doppler Imaging

Chung ES, Leon AR, Tavazzi L, Sun J-P, Nihoyannopoulos P, Merlino J, Abraham WT, Ghio S, Leclercq C, Bax JJ, Yu C-M, Gorcsan J, St John Sutton M, De Sutter J, Murillo J. , 2008, Circulation

Multi-centre study testing if echocardiographic measures of mechanical dyssynchrony could predict CRT response (clinical score and LV reverse remodelling). The study was negative, concluding that none of the 12 tested measures of mechanical dyssynchrony could be recommended to improve patient selection for CRT .

Echocardiography, dyssynchrony, and the response to cardiac resynchronization therapy

Tissue Doppler Imaging

Yu CM, Sanderson JE, Gorcsan J 3rd, 2010, Eur Heart J

This review article discusses how to better select patients for CRT to increase CRT response rate. The authors emphasise the importance of correction of mechanical dyssynchrony for CRT response and the article descirbes the various echocardiographic methodologies available to detect dyssynchrony.

Echocardiographic prediction of outcome after cardiac resynchronization therapy: conventional methods and recent developments

Tissue Doppler Imaging

Leenders GE, Cramer MJ, Bogaard MD, Meine M, Doevendans PA, De Boeck , 2010, Heart Fail Rev

After an introduction of the echo-physiological principles, this excellent review discusses the concepts and rationale of the available echocardiographic techniques in 2010. It introduces newer quantification methods and discussing some of the unsolved issues that need to be addressed.

Novel speckle- tracking radial strain from routine black-and-white echocardiographic images to quantify dyssynchrony and predict response to cardiac resynchronization therapy

Speckle tracking echocardiography

Suffoletto MS, Dohi K, Cannesson M, Saba S, Gorcsan J , 2006, Circulation

Suffolletto demonstrated that speckle tracking radial strain could quantify dyssynchrony. The time difference in peak septal wall–to–posterior wall strain ≥130 ms could predict CRT response by an immediate increase in stroke volume and a significant increase in ejection fraction at long term follow-up.

Combined Longitudinal and Radial Dyssynchrony Predicts Ventricular Response After Resynchronization Therapy

Speckle tracking echocardiography

Gorcsan J III, Tanabe M, Bleeker GB, Suffoletto MS, Thomas NC, Saba S, Tops LF, Schalij MJ, Bax JJ , 2007, J Am Coll Cardiol.

Combined patterns of longitudinal (Tissue Doppler imaging) and radial dyssynchrony (speckle tracking echocardiography) can be predictive of LV functional response after CRT.

Usefulness of echocardiographic dyssynchrony in patients with borderline QRS duration to assist with selection for cardiac resynchronization therapy

Speckle tracking echocardiography

Oyenuga O, Hara H, Tanaka H, Kim HN, Adelstein EC, Saba S, Gorcsan J 3rd, 2010, JACC Cariovasc Imaging

Radial dyssynchrony by speckle tracking strain was associated with EF and reverse remodeling response to CRT in patients with borderline QRS duration.

Simple regional strain pattern analysis to predict response to cardiac resynchronization therapy: rationale, initial results, and advantages

Speckle tracking echocardiography

Risum N1, Jons C, Olsen NT, Fritz-Hansen T, Bruun NE, Hojgaard MV, Valeur N, Kronborg MB, Kisslo J, Sogaard P, 2012, Am Heart J

The classical strain pattern in LBBB is often associated with an early contraction in one wall and prestretching of the opposing wall followed by late contraction. This study explored the ability of the classical strain pattern to predict CRT response (reduction of end-systolic volume ≥15% at six months) and compared this to time-to-peak measurements from velocity and deformation analysis. The study showed that the classical strain pattern was highly predictive of CRT response and was superior to time-to-peak mehtods.

Multicentre study using strain delay index for predicting response to cardiac resynchronization therapy (MUSIC study).

Speckle tracking echocardiography

Lim P, Donal E, Lafitte S, Derumeaux G, Habib G, Réant P, Thivolet S, Lellouche N, Grimm RA, Gueret P, 2011, Eur J Heart Fail

This study aimed to assess the accuracy of the strain delay index (SDI) in predicting responses to CRT in 235 heart failure patients. SDI was defined as the sum of difference between end-systolic and peak longitudinal strain across the 16 segments. SDI correlated with reverse remodelling (≥15% reduction in end-systolic volume at six months) in both wide and narrow QRS patients and ischaemic and non-ischaemic patients. The authors suggest that SDI may identify responders to CRT.

Myocardial contractile reserve during exercise predicts left ventricular reverse remodelling after cardiacresynchronization therapy

contractile reserve assessment

Lancellotti P, Senechal M, Moonen M, Donal E, Magne J, Nellessen E, Attena E, Cosyns B, Melon P,Piérard L, 2009, Eur J Echocardiogr

This study aimed to investigate the potential impact of myocardial contractile reserve on reverse remodeling as assessed as a reduction of ≥15% in end systolic volume at six months with CRT pacing. 51 heart failure patients underwent exercise Doppler echocardiography to assess global contractile reserve and local contractile reserve (assessed by speckle tracking) in the region of the LV lead. Contractile reserve was directely related to improvement of LVEF and reverse remodelling at six months. The authors concluded that myocardial global and regional reserve was highly predictive of reverse remodeling/ CRT response.

Assessment of apical rocking: a new, integrative approach for selection of candidates for cardiac resynchronization therapy

Mechanical abnormalities

Szulik M, Tillekaerts M, Vangeel V, Ganame J, Willems R, Lenarczyk R, Rademakers F, Kalarus Z, Kukulski T, Voigt JU., 2010, Eur J Echocardiogr

This study tested the predictive value of LV apical rocking for response to CRT. Apical rocking was quantified and visually assessed. They found that apical rocking to be a new method to assess dyssynchrony and that it predicted CRT response better than conventional methods.

Toward understanding response to cardiac resynchronization therapy: left ventricular dyssynchrony is only one of multiple mechanisms

Mechanical abnormalities

Parsai C, Bijnens B, Sutherland GR, Baltabaeva A, Claus P, Marciniak M, Paul V, Scheffer M, Donal E, Derumeaux G, Anderson L , 2008, Eur Heart J

Four different pathological mechanisms of dyssynchrony were identified in CRT patients, among which septal flash. Correction of these mechanisms was associated with CRT response and LV dyssynchrony is only one of these mechanisms.

Incremental value of inefficient deformation indices for predicting response to cardiac resynchronization therapy

Mechanical abnormalities

Chan Y-H, Wu L-S, Kuo C-T, Wang C-L, Yeh Y-H, Ho W-J, Hsu L-A , 2013, J Am Soc Echocardiogr

119 CRT candidates were analysed according to septal systolic rebound stretch, the strain delay index, the septal to lateral delay and the 12-segment standard deviation of time to peak strain. Combined systolic rebound stretch in the septal wall and favorable characteristics may help identify CRT responders.

Relationship between Two- Dimensional Speckle-Tracking Septal Strain and Response to Cardiac Resynchronization Therapy in Patients with Left Ventricular Dysfunction and Left Bundle Branch Block: A Prospective Pilot Study

Mechanical abnormalities

Maréchaux S, Guiot A, Castel AL, Guyomar Y, Semichon M, Delelis F, Heuls S, Ennezat PV, Graux P, Tribouilloy C , 2014, J Am Soc Echocardiogr

In this study, they identified three patterns of longitudinal septal deformation with speckle tracking echocardiography. Pattern 1 (double-peaked systolic shortening) and pattern 2 (early pre-ejection shortening peak followed by prominent systolic stretch) were highly predictive of CRT response.

Combined score using clinical, electrocardiographic, and echocardiographic parameters to predict left ventricular remodeling in patients having had cardiac resynchronization therapy six months earlier.

Mechanical abnormalities

Brunet-Bernard A, Maréchaux S, Fauchier L, Guiot A, Fournet M, Reynaud A, Schnell F, Leclercq C, Mabo P, Donal E., 2014, Am J Cardiol

This study found that using a combined score of clinical, echocardiographic and eletrocardiographic parameters before CRT implantation could predict LV reverse remodelling / response in heart failure patients.

Validation of an echocardiographic multiparametric strategy to increase responders patients after cardiac resynchronization: a multicentre study

Multiparametric approach

Lafitte S, Reant P, Zaroui A, Donal E, Mignot A, Bougted H, Belghiti H, Bordachar P, Deplagne A, Chabaneix J, Franceschi F, Deharo JC, Dos Santos P, Clementy J, Roudaut R, Leclercq C, Habib G, 2009, Eur Heart J

This multicentre study aimed to investigate to value of a multiparametric approach to predict CRT response (reduction in end-systolic volume ≥15% at six months). Echocardiography analysis focused on the following parameters: atrioventricular dyssynchrony, interventricular dyssynchrony, and intraventricular dyssynchrony that integrated radial (PSAX M-mode) and longitudinal [tissue Doppler imaging (TDI)] evaluations for spatial (wall to wall) and temporal (wall end-systole to mitral valve opening) dyssynchrony diagnosis. Using a multiparametric approach, increased the specificity and reduced the rate of false positive results compared to using single parameters of dyssynchrony. In conclusion a multiparametric echocardiographic strategy based on the association of conventional criteria was a better indicator of CRT response than the existing single parametric approaches.

Echocardiographic predictors of reverse remodeling after cardiac resynchronization therapy and subsequent events

Multiparametric approach

Park JH1, Negishi K, Grimm RA, Popovic Z, Stanton T, Wilkoff BL, Marwick TH., 2013, Circ Cardiovasc Imaging

This study sought to develop a multiparametric echocardiographic approach to predict CRT response. The single parameters included among others chamber dimensions and volumes as well as speckle tracking longitudinal strain. The combination of the single parameters into an echocardiographic score predicted both reverse remodeling at one year and death and heart failure events during a follow-up of 57±22 months.

Assessment of intraventricular mechanical dyssynchrony and prediction of response to cardiac resynchronization therapy: comparison between tissue Doppler imaging and real-time three-dimensional echocardiography

3D ECHO

Kleijn SA1, van Dijk J, de Cock CC, Allaart CP, van Rossum AC, Kamp O., 2009, J Am Soc Echocardiogr

A study comparing mechanical dyssynchrony assessed by tissue Doppler imaging and real time 3D echocardiography. There were found marked differences between the two techniques for finding mechanical dyssynchrony. The authors concluded that mechanical dyssynchrony by 3D echocardiography might be an appropriate alternative to TDI for prediction of CRT response.

Usefulness of left ventricular systolic dyssynchrony by real-time three-dimensional echocardiography to predict long-term response to cardiac resynchronization therapy

3D ECHO

Soliman OI1, Geleijnse ML, Theuns DA, van Dalen BM, Vletter WB, Jordaens LJ, Metawei AK, Al-Amin AM, ten Cate FJ., 2009, Am J Cardiol

3D echocardiographic dyssynchrony was assessed and was shown to predict CRT response (≥15% reduction in LV end-systolic volume by 3D-echocardiography).

Real-time three-dimensional echocardiography permits quantification of left ventricular mechanical dyssynchrony and predicts acute response to cardiac resynchronization therapy

3D ECHO

Marsan NA, Bleeker GB, Ypenburg C, Ghio S, van de Veire NR, Holman ER, van der Wall EE, Tavazzi L, Schalij MJ, Bax JJ, 2008, J Cardiovasc Electrophysiol

By real time 3D echocardigraphy, mechanical dyssynchrony was assessed as SD of time to reach the minimum systolic volume for 16 LV segments (referred to as systolic dyssynchrony index) in heart failure patients scheduled for CRT. Systolic dyssynchrony index was highly predictive of acute response to CRT (defined as a reduction of end systolic volume of ≥15% immediately after CRT) .

Comparison of three-dimensional echocardiographic software packages for assessment of left ventricular mechanical dyssynchrony and prediction of response to cardiac resynchronization therapy

3D ECHO

Aly MFA, Kleijn SA, de Boer K, Abd El-Hady YA, Sorour KA, Kandil HI, van Rossum AC, Kamp O , 2013, Eur Heart J Cardiovasc Imaging

3D echocardiographic dyssynchrony was assessed using the QLAB software and the TomTec software. They concluded that different 3DE software packages for the assessment of mechanical dyssynchrony should not be used interchangeably until better software standardisation is achieved.

A meta-analysis of left ventricular dyssynchrony assessment and prediction of response to cardiac resynchronization therapy by three-dimensional echocardiography

3D ECHO

Kleijn SA, Aly MF, Knol DL, Terwee CB, Jansma EP, Abd El-Hady YA, Kandil HI, Sorour KA, van Rossum AC, Kamp O, 2012, Eur Heart J Cardiovasc Imaging

In this meta-analysis, the total of 73 studies that evaluated the assessment of LV dyssynchrony by 3DE were eligible. The systolic dyssynchrony index (SDI) for 16 segments, being the predominant 3DE dyssynchrony parameter, was used for data pooling. Results demonstrated that LV dyssynchrony assessment by 3D echocardiography was feasible in 94% of studied subjects. Systolic dyssynhcrony index had good accuracy to predict treatment response. The study concludes that 3D echocardiography is a feasible and reliable tool for assessment of LV dyssynchrony and may have additional value to current selection criteria for accurate prediction of response to CRT.

Impact of clinical and echocardiographic response to cardiac resynchronization therapy on long-term survival

3D ECHO

Bertini M, Höke U, van Bommel RJ, Ng AC, Shanks M, Nucifora G, Auger D, Borleffs CJ, van Rijnsoever EP, van Erven L, Schalij MJ, Marsan NA, Bax JJ, Delgado V., 2013, Eur Heart J Cardiovasc Imaging

This meta-analysis aimed to evaluate the feasibility and reliability of LV dyssynchrony assessment by three-dimensional (3D) echocardiography, determine clinically useful reference values in healthy subjects and heart failure patients, and examine the accuracy of 3D echocardiography to predict response to CRT. It concludes that 3D echocardiography is a feasible and reliable tool for assessment of LV dyssynchrony and may have additional value to current selection criteria for accurate prediction of response to CRT.

Cardiac magnetic resonance-derived anatomy, scar, and dyssynchrony fused with fluoroscopy to guide LV lead placement in cardiac resynchronization therapy: a comparison with acute haemodynamic measures and echocardiographic reverse remodelling 

CMR

Shetty AK, Duckett SG, Ginks MR, Ma Y, Sohal M, Bostock J, Kapetanakis S, Singh JP, Rhode K, Wright M, O'Neill MD, Gill JS, Carr-White G, Razavi R, Rinaldi CA, 2013, Eur Heart J Cardiovasc Imaging

The aim of the study was to determine whether cardiac magnetic resonance (CMR)-guided CRT may improve the acute and the chronic response. CMR targets were defined as the latest three activated segments with <50% scar. Acute haemodynamic response was assessed with intraventricular wire and the chronic response as echocardiographic reverse remodeling at six months. The mean change in LVdP/dtmax was better for LV lead placement in CMR target than in "any segment" or guided by coronary sinus venography. Of the 60% of responders, 92% were CMR target paced, while only 50% of non-responders were paced in a CMR target segment. In conclusion, CMR guidance may represent a clinically useful tool for CRT.

Pre- and intra-procedural predictors of reverse remodeling after cardiac resynchronization therapy: an MRI study

CMR

Cochet H, Denis A, Ploux S, Lumens J, Amraoui S, Derval N, Sacher F, Reant P, Lafitte S, Jais P, Laurent F, Ritter P, Montaudon M, Bordachar P, 2013, J Cardiovasc Electrophysiol

This study aimed to identify pre- adn intraprocedural predictors of CRT response using cardiac magnetic resonance (CMR). In conclusion they found that intra-LV dyssynchrony (defined as the maximal delay between first peaks of radial wall motion over 20 segments) and scar extent (quantified by late gadolinium enhancement) were independent predictors of reverse remodeling after CRT. Scar at the pacing site was assosciated with less reverse remodelling.

Cardiac magnetic resonance assessment of dyssynchrony and myocardial scar predicts function class improvement following cardiac resynchronization therapy

CMR

Bilchick V, Wu KC, Helm RH, Weiss RG, Lima JA, Berger RD, Tomaselli GF, Bluemke DA, Halperin HR, Abraham T, Kass DA, Lardo AC, 2009, JACC Cardiovasc Imaging

Cardiac magnetic resonance (CMR)-myocardial tagging was used to assess circumferential mechanical dyssynchrony in heart failure patients. CMR-tagging predicted improvement of functional class after CRT.

Effect of total scar burden on contrast-enhanced magnetic resonance imaging on response to cardiac resynchronization therapy

CMR

Ypenburg C, Roes SD, Bleeker GB, Kaandorp TAM, de Roos A, Schalij MJ, van der Wall EE, Bax JJ, 2007, Am J Cardiol

34 patients with ischaemic cardiomyopathy underwent a contrast-enhanced magnetic resonance imaging to determine total scar burden using a 17-segment model with a five-point hyperenhancement scale. They showed a significant correlation between total scar burden at baseline and change in LV end-systolic volume after six months of CRT.

Echo-guided LV lead placement to improve outcome in CRT

Impact of left ventricular lead position in cardiac resynchronization therapy on left ventricular remodelling. A circumferential strain analysis based on 2D echocardiography

Becker M, Kramann R, Franke A, Breithardt OA, Heussen N, Knackstedt C, Stellbrink C, Schauerte P, Kelm M, Hoffmann R, 2007, Eur Heart J

Speckle tracking echocardiography was used to determine the optimal LV lead position as the site with latest peak negative systolic circumferential strain prior to CRT. Echoguided optimal LV lead position in CRT resulted in greater improvement in LV function and more LV reverse remodelling than non-optimal LV lead position.

Targeted left ventricular lead placement to guide cardiac resynchronization therapy: the TARGET study: a randomized, controlled trial (TARGET)

Khan FZ, Virdee MS, Palmer CR, Pugh PJ, O'Halloran D, Elsik M, Read PA, Begley D, Fynn SP, Dutka DP, 2012, J Am Coll Cardiol

This study tested the value of echoguided LV lead placement. The LV lead was placed at the latest site of peak contraction as assessed by two-dimensional radial strain speckle tracking technique. The use of speckle-tracking echocardiography to target LV lead placement improved rate of reverse remodelling/response and reduced the combinded endpoint of death and heart failure-hospitalisations.

Echocardiography-guided left ventricular lead placement for cardiac resynchronization therapy: results of the Speckle Tracking Assisted Resynchronization Therapy for Electrode Region trial (STARTER)

Saba S, Marek J, Schwartzman D, Jain S, Adelstein E, White P, Oyenuga OA, Onishi T, Soman P, Gorcsan J., 2013, Circ Heart Fail

Echoguided LV lead placement was performed by positioning the LV lead at the site of the latest time to peak radial strain on speckle-tracking echocardiography. This echoguided LV lead placement improved patient outcome free from heart failure-hospitalisation and death.

Prediction of ventricular arrhythmias in CRT patients

Antiarrhythmic effect of reverse  ventricular remodeling induced by cardiac resynchronization therapy: the InSyncICD (Implantable Cardioverter-Defibrillator) Italian Registry

Di Biase L, Gasparini M, Lunati M, Santini M, Landolina M, Boriani G, Curnis A, Bocchiardo M, Vincenti A, Denaro A, Valsecchi S, Natale A, Padeletti L; InSync/InSync ICD Italian Registry Investigators., 2008, J Am Coll Cardiol

Occurence of ventricular arrhythmias in CRT patients correlated inversely to degree of reverse remodelling as assessed by reduction in LV end-systolic volume.

Reverse remodeling and the risk of ventricular tachyarrhythmias in the MADIT-CRT

Barsheshet A, Wang PJ, Moss AJ, Solomon SD, Al-Ahmad A, McNitt S, Foster E, Huang DT, Klein HU, Zareba W, Eldar M, Goldenberg I., 2011, J Am Coll Cardiol

Reverse remodeling as defined by a reduction in LV end-systolic volume ≥25% at one year was assosciated with a reduction of life threatening ventricular arrhythmias (MADIT-CRT substudy).

Predictors of sustained ventricular arrhythmias in cardiac resynchronization therapy

Friedman DJ, Altman RK, Orencole M, Picard MH, Ruskin JN, Singh JP, Heist EK., 2012, Circ Arrhythm Electrophysiol

Baseline LV end-systolic diameter was a strong predictor of ventricular arrhythmias in CRT patients.

Use of myocardial scar characterization to predict ventricular arrhythmia in cardiac resynchronization therapy

Fernández-Armenta J, Berruezo A, Mont L, Sitges M, Andreu D, Silva E, Ortiz-Pérez JT, Tolosana JM, de Caralt TM, Perea RJ, Calvo N, Trucco E, Borràs R, Matas M, Brugada J, 2012, Europace

The presence, size and heterogeneity of myocardial scars assessed by CMR with late gadelinium enhancement, predicted appropriate ICD therapy in heart failure patients with CRT. 

Dyssynchrony and the risk of ventricular arrhythmias

Kutyifa V, Pouleur AC, Knappe D, Al-Ahmad A, Gibinski M, Wang PJ, McNitt S, Merkely B, Goldenberg I, Solomon SD, Moss AJ, Zareba W., 2012, JACC Cardiovasc Imaging

CRT induced improvement of LV dyssynchrony (assessed as SD of time to peak longitudinal strain from 12 apical LV segments by speckle-tracking technique) was assosciated with less ventricular arrhythmias in patients with LBBB and mild heart failure (MADIT-CRT substudy).

Mechanical Dyssynchrony after Cardiac Resynchronization Therapy for Severely Symptomatic Heart Failure Is Associated with Risk for Ventricular Arrhythmias

Haugaa KH, Marek JJ, Ahmed M, Ryo K, Adelstein EC, Schwartzman D, Saba S, Gorcsan J., 2014, J Am Soc Echocardiogr

Persistent or new mechanical dyssynchrony (assessed by speckle-tracking radial strain anteroseptal-to-posterior-wall delay) after CRT was assosciated with an increased rate of ventricular arrhythmias or death.

Effect of echocardiography-guided left ventricular lead placement for cardiac resynchronization therapy on mortality and risk of defibrillator therapy for ventricular arrhythmias in heart failure patients (from the Speckle Tracking Assisted Resynchronization Therapy for Electrode Region [STARTER] trial)

Adelstein E, Alam MB, Schwartzman D, Jain S, Marek J, Gorcsan J, Saba S., 2014, Am J Cardiol

Echo-guided LV lead placement by the use of speckle tracking radial strain, improved survival free from defibrillator therapy in CRT patients.

Prediction of heart failure events and mortality in CRT patients

Left ventricular resynchronization is mandatory for response to cardiac resynchronization therapy: analysis in patients with chocardiographic evidence of left ventricular dyssynchrony at baseline

Tissue Doppler imaging

Bleeker GB, Mollema SA, Holman ER, Van de Veire N, Ypenburg C, Boersma E, van der Wall EE, Schalij MJ, Bax JJ, 2007, Circulation

LV dyssynchrony was assessed by TDI as maximum delay in peak myocardial velocities between the LV segments before and six months after CRT implantation. Improvement of LV dyssynchrony after CRT was an acute phenomenon and predicted response to CRT at six-month follow-up in patients with echocardiographic evidence of LV dyssynchrony at baseline.

Predictors and treatment response with cardiac resynchronization therapy in patients with heart failure characterized by dyssynchrony: a pre-defined analysis from the CARE-HF trial

Interventricular mechanical delay

Richardson M, Freemantle N, Calvert MJ, Cleland JG, Tavazzi L; CARE-HF Study Steering Committee and Investigators, 2007, Eur Heart J

Mechanical dyssynchrony was assessed by echocardiography as interventricular mechanical delay (IVMD) in 813 heart failure patients enrolled in the CARE-HF study. Patients with echocardiographic evidence of more severe IVMD and low systolic blood pressure obtain greater benefit from CRT. 

Relationship of echocardiographic dyssynchrony to long-term survival after cardiac resynchronization therapy

Tissue Doppler imaging

Gorcsan J 3rd, Oyenuga O, Habib PJ, Tanaka H, Adelstein EC, Hara H, McNamara DM, Saba S., 2010, Circulation

229 consecutive class III to IV heart failure patients were studied. Dyssynchrony before CRT was defined as tissue Doppler velocity opposing-wall delay ≥65 milliseconds, 12-site SD (Yu Index) ≥32 milliseconds, speckle tracking radial strain anteroseptal-to-posterior wall delay ≥130 milliseconds, or pulsed Doppler interventricular mechanical delay ≥40 milliseconds. Abscence of echocardiographic dyssynchrony was associated with significantly less favourable outcome free from death, heart transplantation or LVAD implantation.

Mechanical dyssynchrony evaluated by tissue Doppler cross-correlation analysis is associated with long-term survival in patients after cardiac resynchronization therapy

Tissue Doppler imaging

Risum N, Williams ES, Khouri MG, Jackson KP, Olsen NT, Jons C, Storm KS, Velazquez EJ, Kisslo J, Bruun NE, Sogaard P, 2013, Eur Heart J

In this study pre-implant assessment of longitudinal mechanical dyssynchrony using cross-correlation analysis (XCA) was tested for association with long-term survival and compared with other tissue Doppler imaging (TDI)-derived indices. Mechanical dyssynchrony was assessed from TDI velocity curves using time-to-peak opposing wall delay (OWD) ≥80 ms, Yu index ≥32 ms, and the maximal activation delay (AD-max) >35 ms. AD-max was calculated by XCA of the TDI-derived myocardial acceleration curves. Mechanical dyssynchrony assessed by AD-max was a significantly stronger predictor of long-term survival than other TDI-derived indices.

Dyssynchrony by speckle-tracking echocardiography and response to cardiac resynchronization therapy: results of the Speckle Tracking and Resynchronization (STAR) study

Speckle tracking echocardiography

Tanaka H, Nesser HJ, Buck T, Oyenuga O, Jánosi RA, Winter S, Saba S, Gorcsan J 3rd, 2010, Eur Heart J

Baseline dyssynchrony was evaluated by four echocardiographic speckle tracking strain methods; radial, circumferential, transverse, and longitudinal (≥130 ms opposing wall delay for each). Dyssynchrony by speckle-tracking echocardiography using radial and transverse strains was associated with EF response and long-term outcome following CRT.

Relative merits of left ventricular dyssynchrony, left ventricular lead position, and myocardial scar to predict long-term survival of ischemic heart failure patients undergoing cardiac resynchronization therapy

Speckle-tracking echocardiography

Delgado V, van Bommel RJ, Bertini M, Borleffs CJ, Marsan NA, Arnold CT, Nucifora G, van de Veire NR, Ypenburg C, Boersma E, Holman ER, Schalij MJ, Bax JJ, 2011, Circulation

397 ischemic heart failure patients, two-dimensional speckle tracking imaging was performed to assess radial strain. LV radial dyssynchrony was defined as a time delay of peak radial strain of ≥130ms between anteroseptal and posterior segments and the latest activated segment was identified. Segments with radial strain ≤16.5% were considered to have extensive myocardial scars. Baseline LV radial dyssynchrony, discordant LV lead position, and myocardial scar in the region of the LV pacing lead were independent determinants of long-term prognosis in ischaemic heart failure patients treated with cardiac resynchronisation therapy. Larger baseline LV dyssynchrony predicted superior long-term survival, whereas discordant LV lead position (LV lead not placed at the latest activated segment) and myocardial scar predicted worse outcome.

Dyssynchrony, contractile function, and response to cardiac resynchronization therapy

Speckle-tracking echocardiography

Knappe D, Pouleur AC, Shah AM, Cheng S, Uno H, Hall WJ, Bourgoun M, Foster E, Zareba W, Goldenberg I, McNitt S, Pfeffer MA, Moss AJ, Solomon SD; Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy Investigators., 2011, Circ Heart Fail

Mild to moderate baseline mechanical dyssynchrony (assessed as SD of time to peak transverse strain of 12 LV segments by speckle tracking echocardiography) and greater baseline contractile function (global longitudinal strain) were assosciated with CRT benefit defined as freedom from death or heart failure events (MADIT-CRT substudy).

Cardiac-resynchronization therapy in heart failure with a narrow QRS complex (ECHO-CRT)

Tissue Doppler Imaging and Speckle-tracking echocardiography

Ruschitzka F, Abraham WT, Singh JP, Bax JJ, Borer JS, Brugada J, Dickstein K, Ford I, Gorcsan J 3rd, Gras D, Krum H, Sogaard P, Holzmeister J; EchoCRT Study Group, 2013, N Engl J Med

This multicentre, international randomised study, aimed to investigate the potentional usefulness of CRT in heart failure patients with narrow QRS < 130ms and showing echocardiographic mechanical dyssynchrony. Mechanical dyssynchrony was defined by TDI as an opposing wall delay of peak velocity of ≥ 80 ms or by speckle tracking as a delay in peak radial strain of ≥ 130ms between the anteroseptal to posterior segments. All patients received a CRT and were randomised to CRT turned on or off. The primary endpoint was a composite of all cause death and heart failure hospitalisations. The study was stopped early. Patients with CRT turned on had a significant higher incidence of the primary outcome than patients wiht CRT turned off. The study concluded that in patients with systolic heart failure and a QRS duration of less than 130 msec, CRT does not reduce the rate of death or hospitalisation for heart failure and may increase mortality.

Impact of scar burden by single-photon emission computed tomography myocardial perfusion imaging on patient outcomes following cardiac resynchronization therapy

Nuclear imaging

Adelstein EC, Tanaka H, Soman P, Miske G, Haberman SC, Saba SF, Gorcsan J 3rd, 2011, Eur Heart J

Myocardial scar burden was assessed by SPECT. Extensive scar burden in patients with ischaemic cardiomyopahty unfavourably affected clinical and LV functional outcomes after CRT, regardless of baseline dyssynchrony measures.

CRT induced changes in myocardial function

Improvement of left ventricular myocardial short-axis, but not long-axis function or torsion after cardiac resynchronisation therapy: an assessment by two-dimensional speckle tracking

Zhang Q, Fung JW, Yip GW, Chan JY, Lee AP, Lam YY, Wu LW, Wu EB, Yu CM, 2008, Heart

This study aimed to evaluate whether short-axis function plays a part in determining left ventricular (LV) geometric and functional improvement after CRT. In 39 CRT patients 2D speckle tracking echocardiography was performed at baseline and three months after CRT to assess mean systolic circumferential, radial and longitudinal strain and torsion. In conclusion, the improvement of LV short-axis function (circ and radial strain) but not long-axis function or torsion contributed to the improvement in LV global function and geometry.

Changes in global left ventricular function by multidirectional strain assessment in heart failure patients undergoing cardiac resynchronization therapy

Delgado V, Ypenburg C, Zhang Q, Mollema SA, Fung JW, Schalij MJ, Yu CM, Bax JJ, 2009, J Am Soc Echocardiogr

The aim of this study was to evaluate the acute and late effects of CRT on multidirectional LV strain assessed by two-dimensional speckle-tracking imaging. Responders (57%) and nonresponders (43%) showed similar baseline values for global circumferential (GCS), radial (GRS) and longitudinal (GLS) strain. At follow-up, significant improvement in multidirectional LV strain, combined with significant reverse LV remodelling and improvement in LVEF, was noted only in responders. In conslusion, speckle-tracking imaging and AFI enable the quantification of multidirectional LV mechanics. Improvement in LV strain in the three orthogonal directions after CRT were related to the extent of reverse LV remodelling after CRT.

Effect of cardiac resynchronization therapy on regional left ventricular function: a speckle tracking strain analysis

Serri K, Lafitte S, Réant P, Amyot R, Sauvé C, Bordachar P, Roudaut R, 2010, Eur J Echocardiogr

The study investigated the effects of biventricular pacing on regional myocardial contractility in 20 patients. During different pacing configurations, acute changes in longitudinal and transverse strains from the basal six LV segments were assessed by speckle tracking technique. In summery, in this acute echocardiographic study, biventricular pacing decreased lateral wall deformation while improving septal wall contraction, thus potentially improving LV contractile pattern.

Redistribution of left ventricular strain by cardiac resynchronization therapy in heart failure patients.

Klimusina J, De Boeck BW, Leenders GE, Faletra FF, Prinzen F, Averaimo M, Pasotti E, Klersy C, Moccetti T, Auricchio A, 2011, Eur J Heart Fail

By speckle tracking echocardiography, the LV segmental peak radial and longitudinal myocardial strain were assessed. There were pronounced heterogeneous segmental peak strains which could be reversed by CRT.

Impact of Cardiac Resynchronization Therapy on Left Ventricular Mechanics: Understanding the Response through a New Quantitative Approach Based on Longitudinal Strain Integrals

Bernard A, Donal E, Leclercq C, Schnell F, Fournet M, Reynaud A, Thebault C, Mabo P, Daubert JC, Hernandez A, 2015, J Am Soc Echocardiogr

This study demonstrated that longitudinal strain curve integrals had an incremental value in describing regional strain redistribution after CRT with respect to strain peaks alone.

Guidelines and consensus papers- Imaging in CRT patients

2013 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy: the Task Force on cardiac pacing and resynchronization therapy of the European Society of Cardiology (ESC). Developed in collaboration with the European Heart Rhythm Association (EHRA).

Brignole M, Auricchio A, Baron-Esquivias G, Bordachar P, Boriani G, Breithardt OA, Cleland J, Deharo JC, Delgado V, Elliott PM, Gorenek B, Israel CW, Leclercq C, Linde C, Mont L, Padeletti L, Sutton R, Vardas PE; ESC Committee for Practice Guidelines, Zamorano JL, Achenbach S, Baumgartner H, Bax JJ, Bueno H, Dean V, Deaton C, Erol C, Fagard R, Ferrari R, Hasdai D, Hoes AW, Kirchhof P, Knuuti J, Kolh P, Lancellotti P, Linhart A, Nihoyannopoulos P, Piepoli MF,Ponikowski P, Sirnes PA, Tamargo JL, Tendera M, Torbicki A, Wijns W, Windecker S; Document Reviewers, Kirchhof P, Blomstrom-Lundqvist C, Badano LP,Aliyev F, Bänsch D, Baumgartner H, Bsata W, Buser P, Charron P, Daubert JC, Dobreanu D, Faerestrand S, Hasdai D, Hoes AW, Le Heuzey JY, Mavrakis H,McDonagh T, Merino JL, Nawar MM, Nielsen JC, Pieske B, Poposka L, Ruschitzka F, Tendera M, Van Gelder IC, Wilson CM., 2013, Eur Heart J

The guidelines conclude: "Selection of heart failure patients for CRT based on LV mechanical dyssynchrony assessed by imaging techniques is uncertain and should therefore not be used as a selection criterion for CRT. However, data from several observational studies suggest that baseline LV mechanical dyssynchrony and acute resynchronisation effect after CRT are independent determinants of CRT response and long-term outcome."

2012 EHRA/HRS expert consensus statement on cardiac resynchronization therapy in heart failure: implant and follow-up recommendations and management

Daubert J-C, Saxon L, Adamson PB, Auricchio A, Berger RD, Beshai JF, Breithard O, Brignole M, Cleland J, Delurgio DB, Dickstein K, Exner DV, Gold M, Grimm RA, Hayes DL, Israel C, Leclercq C, Linde C, Lindenfeld J, Merkely B, Mont L, Murgatroyd F, Prinzen F, Saba SF, Shinbane JS, Singh J, Tang AS, Vardas PE, Wilkoff BL, Zamorano JL , 2012, Heart Rhythm

This expert consensus statement from the EHRA concluded: "Despite all these limitations and pitfalls, there is some evidence that a comprehensive assessment, in expert hands, which integrates several mechanical dyssynchrony parameters, myocardial viability, and sizes, can help at identifying patients with a higher likelihood to respond."

Echocardiography for cardiac resynchronization therapy: recommendations for performance and reporting--a report from the American Society of Echocardiography Dyssynchrony Writing Group endorsed by the Heart Rhythm Society

Gorcsan J 3rd, Abraham T, Agler DA, Bax JJ, Derumeaux G, Grimm RA, Martin R, Steinberg JS, Sutton MS, Yu CM; American Society of EchocardiographyDyssynchrony Writing Group., 2008, J Am Soc Echocardiogr

This consensus report evaluates the contemporary applications of echocardiography for CRT including relative strengths and technical limitations of several techniques and proposes guidelines regarding current and possible future clinical applications. This is a relatively old consensus document, published before the negative PROSPECT trial.

Current and evolving echocardiographic techniques for the quantitative evaluation of cardiac mechanics:ASE/EAE consensus statement on methodology and indications endorsed by the Japanese Society ofEchocardiography

Mor-Avi V, Lang RM, Badano LP, Belohlavek M, Cardim NM, Derumeaux G, Galderisi M, Marwick T, Nagueh SF, Sengupta PP, Sicari R, Smiseth OA, Smulevitz B, Takeuchi M, Thomas JD, Vannan M, Voigt JU, Zamorano JL, 2011, Eur J Echocardiogr

This consensus paper discusses the different echocardiographic techniques to assess mechanical dyssynchrony and their ability to predict CRT response. Cut-off values to predict response to CRT are reported. The paper concludes that there is no definite role for the echocardiographic measurement of mechanical dyssynchrony to indicate the need for CRT in heart failure patients.