Left ventricular speckle-tracking-derived mechanical dispersion in patients with transthyretin amyloidosis and their first-degree relatives

Abstract Background Mechanical dispersion has shown to predict ventricular (LV) arrhythmias and sudden cardiac death in populations with established cardiac diseases, such as cardiomyopathies and heart failure. Transthyretin amyloid (ATTR) cardiomyopathy arises from deposition of misfolded, insoluble transthyretin (TTR) in extracellular matrix. The disease impacts profoundly cardiac tissue architecture and its mechanical properties. Purpose The aim of this prospective study was assessment of LV speckle-tracking-derived mechanical dispersion in patients with ATTR cardiomyopathy and their first-degree relatives. Methods We present data based on evaluation of 85 patients, including 34 (group 1) index patients with ATTR and 51 (group 2) first-degree relatives who were studied between June 2020 and January 2023. Study protocol included clinical data, free light chain blood immunoglobulins and urine immunofixation, transthoracic echocardiography (TTE) with global longitudinal strain (GLS) analysis, hybrid technique single-photon emission computed tomography and computed tomography (SPECT/CT) with [99mTc] Tc 3,3-disphono-1,2-propanodicarboxylic acid (DPD), genetic testing by an amplicon-based next-generation TTR sequencing approach, and in selected cases cardiac or soft tissue biopsy. Mechanical dispersion was calculated manually from GLS measurements and defined as the standard deviation (SD) of contraction duration from R on the electrocardiogram (ECG) to peak negative longitudinal strain of all LV segments. Results In group 1 patients were older (66.6±11 vs. 50.7±14) and presented with higher New York Heart Association (NYHA) class (2.4± 1 vs. 1.1± 0.6) (p