Up to 30% of selected heart failure patients do not benefit clinically from cardiac resynchronization therapy (CRT). Left ventricular (LV) wall thickness (WT) analyzed using computed tomography (CT) has rarely been evaluated in response to CRT and mitral regurgitation (MR) improvement.

We examined the association of LVWT and the ability for reverse LV remodeling and MR improvement after CRT.

Fifty-four patients scheduled for CRT underwent pre-procedural CT. Reduced LVWT was defined as WT<6mm and quantified as a percentage of total LV area. End points were 6-month clinical and echocardiographic response to CRT (NYHA class, LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV) and LV end-systolic volume (LVEDV)), MR improvement and 2-year major adverse cardiac events (MACE).

Patients were divided in 3 groups according to the percentage of LVWT<6mm area: ≤20%; 20–50% and ≥50%. At 6 months, 75%, 71% and 42% of the patients experienced NYHA improvement in the ≤20%, 20–50% and ≥50% group respectively. Additionally, ≤20% group presented higher LVEF, LVEDV and LVESV positive response rate (86%, 59% and 83% respectively). Both 20–50% and ≥50% groups exhibited a lower LVEF, LVEDV and LVESV positive response rate (52% and 42%; 47% and 45%; 53% and 45%, respectively). Additionally, ≥25% of LVWT<6mm inclusive of at least 1 papillary muscle insertion was the only predictor of lack of MR improvement. Lastly, ≥50% group experienced significantly lower 2-years MACE survival free probability.

WT evaluated using CT could help to stratify the response to CRT and predict MR improvement and outcomes.