Left ventricular geometric remodeling in relation to non-ischemic scar pattern on cardiac magnetic resonance imaging

Abstract

Left ventricular (LV) remodeling and myocardial fibrosis have been linked to adverse heart failure outcomes. Mid wall late gadolinium enhancement (MW-LGE) on cardiac magnetic resonance (CMR) imaging is well-associated with non-ischemic cardiomyopathy (NICM), but prevalence in ischemic cardiomyopathy (ICM) and association with remodeling are unknown. The population comprised patients with systolic dysfunction [LV ejection fraction (LVEF ≤ 40 %)]. CMR was used to identify MW-LGE, conventionally defined as fibrosis of the mid-myocardial or epicardial aspect of the LV septum. 285 patients were studied. MW-LGE was present in 12 %, and was tenfold more common with NICM (32 %) versus ICM (3 %, p < 0.001). However, owing to higher prevalence of ICM, 15 % of patients with MW-LGE had ICM. LV wall stress was higher (p = 0.02) among patients with, versus those without, MW-LGE despite similar systolic blood pressure (p = 0.24). In multivariate analysis, MW-LGE was associated with CMR-quantified LV end-diastolic volume (p = 0.03) independent of LVEF and mass. Incorporation of clinical and imaging variables demonstrated MW-LGE to be associated with higher LV end-diastolic volume (OR 1.13, CI 1.004-1.27 per 10 ml/m(2), p = 0.04) after controlling for presence of NICM (OR 16.0, CI 5.8-44.1, p < 0.001). While more common in NICM, MW-LGE can occur in ICM and is a marker of LV chamber dilation irrespective of cardiomyopathic etiology.

Figure 1. Typical Examples of Mid-Wall Fibrosis

Representative examples of MW-LGE (red arrows) among patients with angiography-evidenced NICM (1A) and ICM (1B). Note presence MW-LGE with concomitant inferior wall myocardial infarction (blue arrow) in the context of ICM (1B).

Figure 2. Mid-Wall Fibrosis Prevalence in Relation to LV Remodeling

Prevalence of MW-LGE in relation to population-based tertiles of LV end-diastolic volume (2A) and wall stress (2B). As shown, MW-LGE prevalence increased stepwise in relation to both LV remodeling parameters (both p<0.05), although magnitude of difference between highest and lowest tertiles were greater for LV volume than for the aggregate parameter of LV wall stress.

Figure 3. Mid-Wall Fibrosis Size in Relation to LV Remodeling

LV end-diastolic volume (mean ± SD) among patients without MW-LGE (black bar), as well as MW-LGE-affected patients (grey bars) stratified into two groups based on fibrosis size (right = top, left = bottom 50%). Note that both groups of MW-LGE-affected patients had larger LV chamber volumes than did those without MW-LGE, with non-significant differences between MW-LGE-affected patients stratified by fibrosis size.