Left ventricular regional remodeling and lead position during cardiac resynchronization therapy

Area of Science:

• Cardiology
• Medical Imaging
• Cardiac Electrophysiology

Background:

• Cardiac resynchronization therapy (CRT) is known to induce left ventricular (LV) remodeling.
• The precise position of the LV lead (LV-LP) significantly influences CRT response and subsequent remodeling patterns.

Purpose of the Study:

• To quantitatively assess segmental LV remodeling in areas concordant, adjacent, and remote to the LV-LP.
• To utilize dynamic cardiac computed tomography (CT) for detailed analysis of LV remodeling post-CRT.

Main Methods:

• Analysis of 107 patients from the "Empiric Versus Imaging-Guided Left Ventricular Lead Placement in Cardiac Resynchronization Therapy" trial.
• Dynamic cardiac CT scans at baseline and 6-month follow-up to measure systolic wall thickening (WT) and LV-LP.
• Segmentation of the LV into 16 segments to evaluate remodeling relative to LV-LP.

Main Results:

• Systolic WT increased by 20% in segments remote to LV-LP (P < .001) but decreased by 19% in concordant segments (P < .001).
• Segments adjacent to LV-LP showed no significant change in WT (-0.1%, P = .97).
• Nonresponders with nonischemic cardiomyopathy exhibited reduced WT in concordant/adjacent segments and no WT increase in remote segments.

Conclusions:

• CRT-induced systolic WT changes are location-dependent: remote segments thicken, concordant segments thin, and adjacent segments remain stable.
• Nonresponders with nonischemic cardiomyopathy show detrimental segmental function changes, warranting further investigation for optimal management.