Preservation of Circumferential and Radial Left Ventricular Function as a Mitigating Mechanism for Impaired Longitudinal Strain in Early Cardiac Amyloidosis. 

 -  2023 
<br/><br/>Available online from MWHC library: 1995 - present 
<br/><br/> BACKGROUND: In patients with cardiac amyloidosis (CA), left ventricular ejection fraction (LVEF) is frequently preserved, despite commonly reduced global longitudinal strain (GLS). We hypothesized that non-longitudinal contraction may initially serve as a mitigating mechanism to maintain cardiac output, and studied the relationship between global circumferential (GCS) and radial (GRS) strain with LVEF and extracellular volume (ECV), a marker of amyloid burden.  CONCLUSIONS: Among CA patients with preserved LVEF, preserved GCS and GRS despite near-universally impaired GLS may be explained by an initial predominantly subendocardial involvement, where mostly longitudinal fibers are located. If confirmed in future studies, these findings may facilitate identification of patients with early stages of CA, when treatments may be most effective. Copyright © 2023. Published by Elsevier Inc.  METHODS: CA patients who underwent cardiac magnetic resonance (CMR) (n=140, 70.7+/-11.5 years, 66% male) or echocardiography (n=67, 71+/-13 years, 66% male), and normal controls (CMR: n=20; echocardiography: n=45) were retrospectively identified. GCS, GLS, and GRS were quantified using feature-tracking CMR or speckle-tracking echocardiography, and compared between CA patients with preserved and reduced LVEF (CAHFpEF, CAHFrEF) and controls. The prevalence of impaired strain (magnitudes <2.5th percentiles of the controls) was compared between CAHFpEF and CAHFrEF, and between ECV quartiles.  RESULTS: While echocardiography-derived GLS was impaired in both CAHFpEF (-13.4+/-3.1%, p<0.003) and CAHFrEF (-9.1+/-3.2%, p<0.003), compared to controls (-20.8+/-2.4%), GCS was more impaired in CAHFrEF compared to both controls (-15.6+/-5.0% vs -32.3+/-3.3%, p<0.003) and CAHFpEF (-30.4+/-5.7%, p<0.003), and did not differ between CAHFpEF and controls (p=0.24). The prevalence of abnormal CMR-derived GCS (p<0.0001) and GRS (p<0.0001) but not GLS (p=0.054) varied significantly across ECV quartiles. 
<br/><br/><br/>English 
<br/><br/><label>ISSN: </label>0894-7317 
<br/><br/><label>Standard No.: </label>10.1016/j.echo.2023.08.005 [doi] S0894-7317(23)00418-2 [pii] 
<br/><br/><label>Subjects--Topical Terms: </label><br/>IN PROCESS -- NOT YET INDEXED
<br/><br/><label>Subjects--Geographic Terms: </label><br/>MedStar Health Research Institute
<br/><br/><label>Index Terms--Function: </label><br/>Journal Article