Geometrical and electrical predictors of cardiac resynchronization therapy response

Abstract

Several studies have demonstrated the beneficial effect of cardiac resynchronization therapy (CRT) in patients with drug-refractory heart failure. A variable proportion, up to 30%, of CRT patients do not benefit from treatment. The lack of response to CRT has a variety of potential causes. The implantation process is fundamental to the success of CRT, since little can subsequently be done to improve the CRT response. The authors reviewed all the geometrical and electrical parameters that could guide the CRT implant and predict its response.

Keywords::

• clinical outcome
• CRT
• heart failure
• pacing
• predictors of response

Financial & competing interests disclosure

R Fazio is an employee of Boston Scientific Italia. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Larger interlead distance on lateral fluoroscopy view is associated with more favorable immediate and mid-term response to cardiac resynchronization therapy (CRT).

• Among patients treated with CRT, those with significant QRS prolongation (>150 ms) appear to derive the most benefit, and those with left bundle brunch block pattern derive more benefit from CRT than patients with right bundle brunch block or those with non-specific intraventricular conduction disturbances.

• QRS shortening after CRT is associated with enhanced reverse ventricular remodeling following CRT.

• Left ventricle lead electrical delay and right ventricle to left ventricle electrical delay is useful during CRT device implantation, because it may help predict hemodynamic response and long-term clinical outcome.

• Larger registries and controlled clinical trials in well-defined patient groups and with well-defined outcome parameters are required to further elucidate the role of geometrical and electrical predictors to CRT response.