Two-dimensional Strain Echocardiography Differentiates Cardiac Amyloidosis from Hypertrophic Cardiomyopathy with Preserved Ejection Fraction

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Abstract

Background: Ejection fraction is a poor parameter to assess left ventricular function in ventricular hypertrophy. It is highly important to analyze aspects of ventricular mechanics that could differentiate cardiac amyloidosis from hypertrophic cardiomyopathy.

Objective: The aim of this study was to compare longitudinal strain and other ventricular mechanical parameters between patients with hypertrophic cardiomyopathy and cardiac amyloidosis, both with preserved ejection fraction.

Methods: A comparative, prospective study was conducted in 15 patients with cardiac amyloidosis [Group (G) 1] and 15 patients with hypertrophic cardiomyopathy (G2), both presenting preserved ejection fraction (>50%). Patients were analyzed with speckle tracking echocardiography and strain and left ventricular (LV) rotational parameters. Longitudinal strain was obtained from apical 4-, 3- and 2-chamber planes. Circumferential strain and ventricular rotation were obtained from LV transverse planes. Twist:
algebraic sum of apical and basal rotation (°), torsion [twist/LV base-apex distance (º/cm)] and the new parameters: deformation product (global longitudinal strain × apical circumferential strain); deformation index: [twist/ longitudinal strain (º/%)] and ejection fraction/global longitudinal strain ratio were calculated.

Results: Patients with cardiac amyloidosis presented significantly lower ejection fraction (58.08%±6.16 vs. 67.15%±8.09; p=0.012) and global longitudinal strain values (–12.61%±4.32 vs. –17.15%±3.95; p=0.008) at the expense of basal segments. No significant differences were found for twist, torsion, and circumferential and radial strain. The product between longitudinal strain and apical
circumferential strain decreased, while the ejection fraction/global longitudinal strain ratio was significantly increased in patients with cardiac amyloidosis.

Conclusions: The product of longitudinal strain × apical circumferential strain and the ejection fraction/global longitudinal strain ratio are useful parameters that allow differentiating cardiac amyloidosis from hypertrophic cardiomyopathy patients.