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What is the best way to optimise cardiac resynchronisation therapy response?

At present, up to 30-40% of patients do not show improvement in left ventricular (LV) performance or clinical symptoms after cardiac resynchronization therapy (CRT). This suboptimal response may be secondary to several factors, such as lack of baseline LV mechanical dyssynchrony, presence of substantial scar, non-optimal LV lead position, atrio-ventricular (AV) dyssynchrony or persistence of LV dyssynchrony after CRT.


Thus, there is a need in clinical practice to extend the benefit of CRT to a larger proportion of patients. But, what is the best way to optimize CRT response? This has been debated in an interesting symposium held at 2013 ESC Congress.

The main conclusions and messages of the Symposium are:

  1. treat with CRT only suitable patients that have both electrical and mechanical LV dyssynchrony (echocardiography may be useful for this);
  2. avoid putting the LV lead in areas that are site of scars (cardiac MRI may be useful for this);
  3. target LV lead to the site of longest delay in mechanical contraction and always avoid the apical region (echocardiography may be useful for this);
  4. optimize AV and ventriculo-ventricular (VV) intervals to improve LV filling and reduce LV dyssynchrony (echocardiography and device-based algorithms may be useful for this).

However, Derek Exner from Calgary, Canada outlined that current evidence does not support AV and VV interval optimization routinely in all patients receiving CRT. Only clinical non-responders to the usual modality of CRT pacing (consisting in simultaneous biventricular pacing with a fixed 100-120 ms interval) really need to undergo an optimization procedure.

This is in agreement with the 2013 Guidelines on cardiac pacing and CRT.


ESC Congress 2013
Session Title: What is the best way to optimise cardiac resynchronisation therapy response?

The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.