Mechanical effects of left ventricular midwall fibrosis in non-ischemic cardiomyopathy

Abstract

BackgroundLeft ventricular (LV) mid-wall fibrosis (MWF), which occurs in about a quarter of patients with non-ischemic cardiomyopathy (NICM), is associated with high risk of pump failure. The mid LV wall is the site of circumferential myocardial fibers. We sought to determine the effect of MWF on LV myocardial mechanics.MethodsPatients with NICM (n = 116; age: 62.8 ± 13.2 years; 67 % male) underwent late gadolinium enhancement cardiovascular magnetic resonance (CMR) and were categorized according to the presence (+) or absence (−) of MWF. Feature tracking (FT) CMR was used to assess myocardial deformation.ResultsDespite a similar LVEF (24.3 vs 27.5 %, p = 0.20), patients with MWF (32 [24 %]) had lower global circumferential strain (Ɛcc: −6.6 % vs −9.4 %, P = 0.004), but similar longitudinal (Ɛll: −7.6 % vs. −9.4 %, p = 0.053) and radial (Ɛrr: 14.6 % vs. 17.8 % p = 0.18) strain. Compared with − MWF, + MWF was associated with reduced LV systolic, circumferential strain rate (−0.38 ± 0.1 vs −0.56 ± 0.3 s−1, p = 0.005) and peak LV twist (4.65 vs. 6.31°, p = 0.004), as well as rigid LV body rotation (64 % vs 28 %, P <0.001). In addition, +MWF was associated with reduced LV diastolic strain rates (DSRcc: 0.34 vs. 0.46 s−1; DSRll: 0.38 vs. 0.50s−1; DSRrr: −0.55 vs. −0.75 s−1; all p <0.05).ConclusionsMWF is associated with reduced LV global circumferential strain, strain rate and torsion. In addition, MWF is associated with rigid LV body rotation and reduced diastolic strain rates. These systolic and diastolic disturbances may be related to the increased risk of pump failure observed in patients with NICM and MWF.

Three-Dimensional Left Ventricular Torsion in Patients With Dilated Cardiomyopathy ― A Marker of Disease Severity ―

“…21 Recent studies have reported that LV twist in patients with systolic heart failure (overall mean LV EF 31%) is reduced within a range of 4.1-6.1 degrees compared with healthy persons. 29- 33 The present result, 4.3±2.0 degrees of LV twist, is consistent with those reports, irrespective of the imaging method.…”

“…In the progression of DCM, mid-myocardial replacement fibrosis disturbs circumferential deformation and twist motion, which results in a "stiffer" LV and leads to deleterious systolic and diastolic ventricular function. 33 This corroborates our finding that LV torsion is more appropriate than longitudinal strain for determining a reduced FC (Figure 3). Furthermore, we demonstrated that LV torsion was strongly associated with the amount of diastolic dysfunction (r=−0.67) in DCM patients.…”

Loss of base‐to‐apex circumferential strain gradient: A specific pattern of Fabry cardiomyopathy?

“…The importance of early diagnosis of Fabry disease and its cardiac manifestations is now well established. Enzyme replacement therapy is more efficient when started early, before the development of irreversible cardiac sequelae, such as fibrosis . Two‐dimensional strain may help provide early detection of Fabry disease among patients with apparent HCM.…”

“…Enzyme replacement therapy is more efficient when started early, before the development of irreversible cardiac sequelae, such as fibrosis. [24][25][26] Two-dimensional strain may help provide early detection of Fabry disease among patients with apparent HCM. Furthermore, in patients with known mutations but without LVH, 2D strain screening may allow the identification of preclinical myocardial damage, leading to an earlier institution of enzyme replacement therapy.…”

Dark blood late enhancement imaging

“…Alternatively, LGE with blood suppression may be achieve my combining either a T2 preparation [9, 11, 13] with IR or by combining a magnetization transfer (MT) preparation with IR [12, 15]. In these schemes, the myocardial signal is reduced relative to the blood signal thereby reducing the inversion times to null the myocardium.…”