Characterization of non-response to cardiac resynchronization therapy by post-procedural computed tomography

Area of Science:

• Cardiology
• Medical Imaging
• Biomedical Engineering

Background:

• Cardiac resynchronization therapy (CRT) is a treatment for heart failure, but some patients do not respond.
• Causes of CRT non-response include mechanical dyssynchrony, myocardial scar, and incorrect left ventricular (LV) lead placement.

Purpose of the Study:

• To evaluate the effectiveness of Late Iodine Enhancement Computed Tomography (LIE-CT) with image subtraction in identifying factors contributing to CRT non-response.

Main Methods:

• LIE-CT was performed on 29 patients 6 months after CRT implantation.
• Analysis included assessment of dyssynchrony, myocardial scar, coronary venous anatomy, and LV lead position relative to scar and mechanical contraction patterns.
• CRT response was defined as a >15% decrease in LV end-systolic volume.

Main Results:

• Non-responders showed significantly worse residual dyssynchrony metrics compared to responders.
• No significant difference in scar presence or extent was observed between groups.
• LV lead placement in non-responders was more frequently over akinetic/dyskinetic or fibrotic areas, and areas with thin myocardium (<6 mm).

Conclusions:

• LIE-CT with image subtraction provides a detailed characterization of patients post-CRT.
• This imaging technique can offer insights into managing patients who do not respond to CRT, particularly by identifying suboptimal LV lead positioning.