Rotational mechanics of the left ventricle in AL amyloidosis

Aims: The aim of this study was to investigate whether alterations in left ventricular (LV) twisting and untwisting motion could be induced by cardiac involvement in patients with immunoglobulin light-chain (AL) systemic amyloidosis. Methods and results: Forty-five patients with AL amyloidosis and 26 control subjects were evaluated. After standard echocardiographic measurement and two-dimensional (2D) speckle tracking echocardiography, LV rotation at both basal and apical planes, twisting, twisting rate, and longitudinal strain were measured. Tissue Doppler imaging (TDI) derived early diastolic peak velocity at septal mitral annulus (E') was also evaluated. Twenty-six of 45 patients with systemic amyloidosis were classified as having cardiac amyloidosis (CA) if the mean value of the LV wall thickness was ≥ 12 mm or not (NCA) if this value was not reached. In NCA patients, both LV twist and untwisting rate were increased while they were decreased in CA patients making them similar to the control group. Longitudinal strain was reduced only in CA patients. Impaired relaxation as indicated by E' values was progressively reduced in the course of the disease. Conclusions: Both twisting and untwisting motions are increased in patients with AL systemic amyloidosis with no evidence of cardiac involvement while they are reduced in patients with evident amyloidosis cardiac involvement. This finding suggests that impaired LV relaxation induces a compensatory mechanism in the early phase of the disease, which fails in more advanced stage when both twisting and untwisting rates are reduced. The increase in LV rotational mechanics could be a marker of subclinical cardiac involvement.