Aim: To determine the feasibility and potential benefit of a full cardiac magnetic resonance (CMR) work-up for assessing the location of scarred myocardium and the region of latest contraction (LCR) in patients with ischaemic cardiomyopathy (ICM) undergoing cardiac resynchronisation therapy (CRT).
Methods: In 30 patients, scar identification and contraction timing analysis was retrospectively performed on CMR images. Fluoroscopic left ventricular (LV) lead positions were scored with respect to scar location, and when placed outside scar, with respect to the LCR. The association between the lead position with respect to scar, the LCR and echocardiographic LV end-systolic volume (LVESV) reduction was subsequently evaluated.
Results: The CMR work-up was feasible in all but one patient, in whom image quality was poor. Scar and contraction timing data were succesfully displayed on 36-segment cardiac bullseye plots. Patients with leads placed outside scar had larger LVESV reduction (-21 ± 21%, n = 19) compared to patients with leads within scar (1 ± 25%, n = 11), yet total scar burden was higher in the latter group. There was a trend towards larger LVESV reduction in patients with leads in the scar-free LCR, compared to leads situated in scar-free segments but not in the LCR (-34 ± 14% vs -15 ± 21%, p = 0.06).
Conclusions: The degree of reverse remodelling was larger in patients with leads situated in a scar-free LCR. In patients with leads situated within scar there was a neutral effect on reverse remodelling, which can be caused both by higher scar burden or lead position. These findings demonstrate the feasibility of a CMR work-up and potential benefit in ICM patients undergoing CRT.
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