Abstract 16911: Myocardial Work: A Novel Measure of Myocardial Performance Differentiates Cardiac Amyloidosis From Hypertensive Hypertrophic Disease
Background: Myocardial strain imaging using speckle tracking echocardiography can be utilized to measure myocardial contractility. Since myocardial contractility varies with afterload, we hypothesized that myocardial work [strain x systolic blood pressure] (Mwk) would be useful to evaluate contractility within the context of the loading conditions. We evaluated Mwk to distinguish hypertensive left ventricular hypertrophy (HLVH) from cardiac amyloidosis (CA), both of which have similar 2-dimensional imaging with concentric LV-mass increase but known to have discrepancy in contractile function.
Methods: Twenty patients with biopsy proven CA was compared to age (65±10 years) and gender (13 male/7 female) matched groups of HLVH and control. CA and HLVH groups were matched for LV wall thickness (15±4 mm). Systolic longitudinal myocardial strains (LStr) were measured using Syngo velocity vector imaging (Siemens Medical Solutions USA Inc., Malvern, PA). Blood Pressure (BP) was recorded immediately before examination. Work was calculated by systolic BP multiplied by LStr. Strain was evaluated in each of six LV segments at the apical 4-chamber view according to AHA/ASE guidelines. Global strain and Mwk were derived as an average of all the segments.
Results: Compared to controls, the HLVH group had reduced global LStr (p=0.02), but had no difference in global Mwk (p=0.22). In contrast, the CA group had significant reduction in both global LStr (p<0.001) and global Mwk (p<0.001). Discrimination between CA and HLVH using ROC analysis was better with global Mwk (AUC 0.90) compared to global LStr (AUC 0.84). The same relationships were also found in regional analysis of the six LV segments.
Conclusions: Mwk was significantly different between CA and HLVH group. Although the HLVH group showed abnormal strain compared to the normal controls, this was likely attributable to afterload differences, because overall Mwk was not noted to be different between these groups.
- © 2013 by American Heart Association, Inc.