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Unique Features

Implantable Cardiac Devices

Ensure CRT Suite

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Clinical Need

Clinical Need

Studies have shown that up to one-third of patients do not experience all of the benefits of cardiac resynchronization therapy (CRT).1-6

Multiple conditions can hamper CRT response:

  • Suboptimal AV/VV timings -- occurs in 45% of CRT non-responders7
  • Atrial fibrillation (AF) -- the single, largest cause of CRT non-response8
  • Threshold elevation -- may lead to loss of CRT and requires in-office follow-up visits to manage LV capture concerns9

Percentage of Patients with Adequate CRT Response1-6

Adequate CRT Response

Detail - Adequate CRT Response

Potential Factors Contributing to Suboptimal CRT Response7

Suboptimal CRT Response

Detail - Suboptimal CRT Response

Important Safety Information

For CRT-D devices, certain programming and device operations may not provide cardiac resynchronization. Changes in a patient's disease and/or medications may alter the efficacy of a device's programmed parameters.



Abraham WT, Fisher WG, Smith AL, et al. Cardiac resynchronization in chronic heart failure. NEJM. 2002;346(24):1845-1853.


Abraham WT, Young JB, León AR, et al. Effects of cardiac resynchronization on disease progression in patients with left ventricular systolic dysfunction, an indication for an implantable cardioverter-defibrillator, and mildly symptomatic chronic heart failure. Circulation. 2004;110(18):2864-2868.


Abraham WT, Leon AR, Hannon C, et al. Results of the InSync III Marquis clinical trial. Heart Rhythm. 2005;2(5): S65.


Abraham WT, Gras D, Yu CM, et al. Results from the FREEDOM Trial - assess the safety and efficacy of frequent optimization of cardiac resynchronization therapy. Presented at the Heart Rhythm Society annual scientific session, Denver, CO, May 2010.


Young JB, Abraham WT, Smith AL, et al. Combined cardiac resynchronization and implantable cardioversion defibrillation in advanced chronic heart failure; the MIRACLE ICD Trial. JAMA. 2003;289(20):2685-2694.


Chung ES, Leon AR, Tavazzi L, et al. Results of the Predictors of Response to CRT (PROSPECT) Trial. Circulation. 2008;117(20):2608-2616.


Mullens W, Grimm RA, Verga T, et al. Insights from a cardiac resynchronization optimization clinic as part of a heart failure disease management program. JACC. 2009; 53(9):765-773.


Knight BP, Desai A, Coman J, et al. Long-term retention of cardiac resynchronization therapy. J Am Coll Cardiol. July 7, 2004;44(1):72-77.


Crossley GH, Mead H, Kleckner K, et al. Automated left ventricular capture management. Pacing Clin Electrophysiol. October 2007; 30(10):1190-1200.

How It Works


AF and CRT

Capture Management