Methods
Study population
We prospectively collected 25 consecutive patients who hospitalized for multiple myeloma and diagnosed with AL-CA between April 2018 and January 2021 in the First Affiliated Hospital of Soochow University. The diagnosis of AL-CA was established on the basis of a characteristic echocardiogram for amyloid and a histological proof of presence of systemic amyloid, in the absence of any other plausible causes of LV hypertrophy10. 3 patients with AF and one with poor imaging were excluded. As a result, 21 patients with AL-CA were enrolled in our study. HHD group consisted with 56 randomly selected patients with hypertensive heart disease matched with age, gender and left ventricular mass index (LVMI). The diagnosis of hypertensive heart disease was based on echocardiographic demonstration of a hypertrophic LV and a history of systemic hypertension in the absence of other cardiac or systemic disease16. Additionally, 25 age- and gender- matched subjects with normal electrocardiography served as a control group.
Echocardiography
The two-dimensional echocardiographic imaging of all patients was performed by GE Vivid E95 equipment (Norway) 3.5 MHz transducer (M5S). Patients were placed in the lateral decubitus position. Electrocardiogram and echocardiography were recorded simultaneously. Measurements were performed according to the guidelines of the American Society of Echocardiography 17. Left ventricular end-systolic diameter and left atrial anteroposterior dimension were measured at end-systole, and left ventricular end-diastolic diameter was measured at end-diastole on parasternal views. End-diastolic septal thickness and posterior wall thickness were assessed on both parasternal views and short axis views. Left ventricular ejection fraction (LVEF) and left atrial ejection fraction were obtained by the biplane Simpson’s method on apical 4-chamber and 2-chamber views. Pulse-wave doppler (PW) was used to measure the peak early diastolic flow velocity (E peak), peak late diastolic flow velocity (A peak) and E/A ratio of mitral valve. PW was also used to measure the e’ of septal and lateral wall and E/e’ in tissue doppler imaging (TDI) mode. Tricuspid regurgitation velocity (TR velocity) was measured by continuous doppler (CW) under the guidance of color doppler on apical 4-chamber views.
LA longitudinal strain analysis
Analysis of two-dimensional speckle tracking echocardiograms was performed using Echo PAC workstation (GE, USA). The images of apical 4-chamber and 2-chamber, which could clearly show the left atrium, were used to analyze left atrial strain by Q-Analysis method. Region of interest (ROI) should include all left atrial myocardium but without pericardium, so the ROI width is usually ≤3mm. Once the region of ROI was established, the analyzer modified the region to ensure the quality of speckle tracking (See Figure1). SD-TPS was used to measure the degree of LA dispersion. It was calculated as the SD of time to peak and expressed as a percentage of the R-R interval18.