Influence of Ventricular Wringing on the Preservation of Left Ventricular Ejection Fraction in Cardiac Amyloidosis

Abstract

The purpose of this work was to determine the influence of myocardial wringing on ventricular function in patients with cardiac amyloidosis (CA). Fifteen healthy volunteers (group 1) and 34 patients with CA (17 with left ventricular ejection fractions [LVEFs]≥53% [group 2] and 17 with LVEFs<53% [group 3]) were evaluated using two-dimensional speckle-tracking echocardiography. A control group of mass-matched patients (n=20) with left ventricular (LV) hypertrophy and LVEFs≥53% was also included. Longitudinal strain (LS), circumferential strain, and LV twist and torsion were calculated. Deformation index (DefI), a new parameter of wringing, calculated as twist/LS, that takes into account actions that occur simultaneously during LV systole (i.e., longitudinal shortening and twist), was evaluated. Torsional and wringing parameters were calculated according to LVEF. Lower global values of LS and circumferential strain were observed among patients with CA (LS: group 1, -20.6±2.5%; group 2, -11.6±4.1%; group 3, -9.0±3.1%; circumferential strain: group 1, -22.7±4.9%; group 2, -14.4±8.0%; group 3, -13.6±3.8%; P<.001 for both). Torsion did not vary between group 2 and group 1 (2.5±1.1°/cm vs 2.7±0.8°/cm, P= NS). In contrast, DefI was greater in group 2 than in group 1 (-1.8±0.8°/% vs -1.0±0.3°/%, P<.01). Torsion and DefI were lower in group 3 (1.2±0.7°/cm and -1.1±0.6°/%, respectively, P<.001 for both) than in group 2. DefI was similar in patients with LV hypertrophy (-1.7±0.6°/%, P= NS) and group2. In patients with CA, preservation of LVEF depends on greater ventricular wringing. DefI, a parameter that integrates the twist and the simultaneous longitudinal shortening of the left ventricle, is a more accurate indicator of the efficacy of this mechanism.