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

• Published in: Journal of cardiovascular magnetic resonance Vol. 18; no. 1; p. 1
• Main Authors: Taylor, Robin J, Umar, Fraz, Lin, Erica L S, Ahmed, Amar, Moody, William E, Mazur, Wojciech, Stegemann, Berthold, Townend, Jonathan N, Steeds, Richard P, Leyva, Francisco
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 05.01.2016; BioMed Central
• Subjects: Aged; Biomechanical Phenomena; Cardiac output; Cardiomyopathies - complications; Cardiomyopathies - diagnosis; Cardiomyopathies - pathology; Cardiomyopathies - physiopathology; Cardiomyopathy; Contrast Media; Development and progression; Diastole; England; Female; Fibrosis; Gadolinium DTPA; Heart diseases; Heart Failure - etiology; Heart Failure - pathology; Heart Failure - physiopathology; Heart ventricle, Left; Heart Ventricles - pathology; Heart Ventricles - physiopathology; Humans; Magnetic Resonance Imaging, Cine; Male; Medical examination; Middle Aged; Myocardium - pathology; Observations; Predictive Value of Tests; Stress, Mechanical; Systole; Torsion, Mechanical; Ventricular Function, Left
• ISSN: 1097-6647; 1532-429X
• DOI: 10.1186/s12968-015-0221-2

Left 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. Patients 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. Despite 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). MWF 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.