Abstract
Background
Numerous trials have demonstrated the effectiveness of cardiac resynchronization therapy (CRT) as an adjunct to medical therapy for the relief of heart failure (HF) symptoms in patients with a wide QRS duration (QRSd). Current guidelines recommend CRT in patients with an EF <35%, medically refractory NYHA Class III–IV HF and QRSd ≥120 ms. Previous studies have demonstrated QRSd as a marker of electrical dyssynchrony fails to predict response to CRT. In addition, studies have demonstrated significant differences in QRSd post CRT between responders and non-responders. Moreover, smaller non-controlled studies demonstrated that HF patients with a narrow QRSd may benefit from CRT. A growing body of evidence suggests that echocardiographic criteria may be a better method to evaluate mechanical dyssynchrony (MD) which may predict those that will benefit from CRT, particularly those with a narrow QRSd. The Resynchronization Therapy In Narrow QRS (RethinQ) study will evaluate mechanical dyssynchrony using echocardiography (both M mode and TDI) as an eligibility requirement for CRT.
Methods
The RethinQ study is a prospective, multi-center, randomized, double blind controlled clinical study. The objective of the RethinQ study is to evaluate the effectiveness of CRT in patients with approved ICD indication, advanced HF (NYHA Classification III), narrow QRSd (<130 ms) and evidence of MD measured by echocardiography.
Conclusion
We hypothesize that patients with narrow QRS <130 ms, advanced HF, and MD as measured by echocardiography will benefit from CRT.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Young, J. B., Abraham, W. T., Smith, A. L., Leon, A. R., Lieberman, R., Wilkoff, B., et al. (2003). Combined cardiac resynchronization and implantable cardioversion defibrillation in advanced chronic heart failure: The MIRACLE ICD trial. JAMA, 289, 2685–2694.
Abraham, W. T., Fisher, W. G., Smith, A. L., Delurgio, D. B., Leon, A. R., Loh, E., et al. (2002). Cardiac resynchronization in chronic heart failure. New England Journal of Medicine, 346(24), 1845–1853.
Cazeau, S., Leclercq, C., Lavergne, T., Walker, S., Varma, C., Linde, C., et al. (2001). Effects of multisite biventricular pacing in patients with heart failure and intraventricular conduction delay. New England Journal of Medicine, 344(12), 873–880.
Higgins, S. L., Hummel, J. D., Niazi, I. K., Giudici, M. C., Worley, S. J., Saxon, L. A., et al. (2003). Cardiac resynchronization therapy for the treatment of heart failure in patients with intraventricular conduction delay and malignant ventricular tachyarrhythmias. Journal of the American College of Cardiology, 42, 1454–1459.
Leclercq, C., & Kass, D. A. (2002). Retiming the failing heart: Principles and current clinical status of cardiac resynchronization. Journal of the American College of Cardiology, 39, 194–201.
Shen, A. Y., Wang, X., Doris, J., & Moore, N. (2004). Proportion of patients in a congestive heart failure management program meeting criteria for cardiac resynchronization therapy. American Journal of Cardiology, 94, 673–676.
Gupta, S. N., Jose, V. J., & Chandy, S. T. (2003). Heart failure: What proportion of patients satisfy the electrocardiographic criteria for cardiac resynchronization therapy. Indian Heart Journal, 55(6), 619–623.
Ghio, S., Constantin, C., Klersy, C., Serio, A., Fontana, A., Campana, C., et al. (2004). Interventricular and intraventricular dyssynchrony are common in heart failure patients, regardless of QRS duration. European Heart Journal, 25, 571–578.
Achilli, A., Sassara, M., Ficili, S., Pontillo, D., Achilli, P., Alessi, C., et al. (2003). Long-term effectiveness of cardiac resynchronization therapy in patients with refractory heart failure and “narrow” QRS. Journal of the American College of Cardiology, 42, 2117–2124.
Yu, C. M., Chan, Y. S., Zhang, Q., Yip, G. W., Chan, C. K., Kum, L. C., et al. (2006) Benefits of cardiac resynchronization therapy for heart failure patients with narrow QRS complexes and coexisting systolic asynchrony by echocardiography. Journal of the American College of Cardiology, 48(11), 2251–2257.
Bleeker, G. B., Holman, E. R., Steendijk, P., Boersma, E., van der Wall, E. E., Schalij, M. J., et al. (2006). Cardiac resynchronization therapy in patients with a narrow QRS complex. Journal of the American College of Cardiology, 48(11), 2243–2250.
Yu, C. M., Yang, H., Lau, C. P., Wang, Q., Wang, S., Lam, L., et al. (2003). Regional left ventricle mechanical asynchrony in patients with heart disease and normal QRS duration: Implication for biventricular pacing. PACE, 26(Pt I), 562–570.
Turner, M. S., Bleasdale, R. A., Vinereanu, D., Mumford, C. E., Paul, V., Fraser, A. G., et al. (2004). Electrical and mechanical components of dyssynchrony in heart failure patients with normal QRS duration and left bundle-branch block. Circulation, 109, 2544–2549.
Bax, J. J., Marwick, T. H., Molhoek, S. G., Bleeker, G. B., van Erven, L., Boersma, E., et al. (2003). Left ventricular dyssynchrony predicts benefit of cardiac resynchronization therapy in patients with end-stage heart failure before pacemaker implantation. American Journal of Cardiology, 92, 1238–1240.
Kaplan, E. L., & Meier, P. (1958). Nonparametric estimation from incomplete observations. Journal of the American Statistical Association, 53, 457–481.
Turk, K., Edel, T., Pires, L., Ip, J., Val Mejias, J., Beau, S., et al. (2004). Cardiac resynchronization therapy in heart failure: Results from the RHYTHM ICD study. Journal of Cardiac Failure, 10(4), S78.
Reuter, S., Garrigue, S., Barold, S. S., Jais, P., Hocini, M., Haissaguerre, M., et al., (2002). Comparison of characteristics in responders versus nonresponders with biventricular pacing for drug-resistant congestive heart failure. American Journal of Cardiology, 89, 346–350.
Cain, P., Baglin, T., Case, C., Spicer, D., Short, L., & Marwick, T. H. (2001). Application of tissue Doppler to interpretation of dobutamine echocardiography and comparison of quantitative angiography. American Journal of Cardiology, 87, 525–531.
Yu, C. M., Chau, E., Sanderson, J. E., Fan, K., Tang, M. O., Fung, W. H., et al. (2002). Tissue Doppler echocardiographic evidence of reverse remodeling and improved synchronicity by simultaneously delay regional contraction after biventricular pacing therapy in heart failure. Circulation, 105, 438–445.
Ansalone, G., Giannantoni, P., Ricci, R., Trambaiolo, P., Laurenti, A., Fedele, F., et al. (2001). Doppler myocardial imaging in patients with heart failure receiving biventricular pacing treatment. American Heart Journal, 142, 881–896.
Sogaard, P., Egeblad, H., Kim, W. Y., Jensen, H. K., Pedersen, A. K., Kristensen, B. O., et al. (2002). Tissue Doppler imaging predicts improved systolic performance and reversed left ventricular remodeling during long-term resynchronization therapy. Journal of the American College of Cardiology, 40, 723–730.
Bax, J. J., Molhoek, S. G., van Erven, L., Voogd, P. J., Somer, S., Boersma, E., et al. (2003). Usefulness of myocardial tissue doppler echocardiography to evaluate left ventricular dyssynchrony before and after biventricular pacing in patients with idiopathic dilated cardiomyopathy. American Journal of Cardiology, 91, 94–97.
Marcus, G. M., Rose, E., Viloria, E. M., Schafer, J., De Marco, T., Saxon, L. A., et al. (2005). Septal to posterior wall motion delay fails to predict reverse remodeling or clinical improvement in patients undergoing cardiac resynchronization therapy. Journal of the American College of Cardiology, 46(12), 208–2214.
Gorcsan, J., 3rd, Kanzaki, H., Bazaz, R., Dohi, K., & Schwartzman, D. (2004). Usefulness of echocardiographic tissue synchronization imaging to predict acute response to cardiac resynchronization therapy. American Journal of Cardiology, 93(9), 1178–1181.
Author information
Authors and Affiliations
Corresponding author
Additional information
An erratum to this article can be found at http://dx.doi.org/10.1007/s10840-007-9192-z
Rights and permissions
About this article
Cite this article
Beshai, J.F., Grimm, R. The resynchronization therapy in narrow QRS study (RethinQ study): Methods and protocol design. J Interv Card Electrophysiol 19, 149–155 (2007). https://doi.org/10.1007/s10840-007-9156-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10840-007-9156-3