Study population and protocol
We enrolled 166 patients of DCMP or ICMP who were come to our center for
diagnostic evaluation between January 2021 and May 2023. Patients were
selected based on inclusion criteria with signs and symptoms of heart
failure, accompanied by echocardiographic evidence of LV dilatation
associated with reduced left ventricular systolic function (LVEF
≤ 40%). The study’s primary aim was to compare echocardiographic and
biochemical parameters of heart failure by evaluating serum biomarker-
NT pro-BNP, echocardiographic parameter of LVEF, GLS, E/e’ with LAAWV.
We enrolled patients based on the inclusion criteria of (1) Patients
aged >18 years, (2) New York Heart Association functional
class II to III with left ventricular ejection fraction ≤40%.
154 patients had echocardiographic images of sufficient quality for
further two-dimensional myocardial deformation analysis and LAAW
velocity. We could not measure TTE-LAWV in 6 patients, because of
obesity, chronic obstructive pulmonary disease, or emaciation, and
another 6 patients didn’t meet the criteria for obesity with a BMI of
<30, and these patients were excluded from the study. These
patients comprise the cohort of the present echocardiographic sub-study.
Study Patients with- (1) Primary valvular heart disease, (2) Acute
myocarditis (onset in the previous three months), (3) Acute myocardial
infarction as suspected by clinical presentation or diagnostic tests,
(4) Obese patient with BMI >30, (5) Patients with other
co-morbidities that may limit life expectancy to less than one year,
were excluded from the study.
Study patients underwent a clinical evaluation and routine laboratory
tests, including complete blood count, creatinine, and B-type
natriuretic peptide (BNP). All the patients underwent transthoracic
echocardiography and were treated according to the guideline and
provided informed consent.
We performed the echocardiographic evaluation using GE Vivid E9
ultrasound machines equipped with a 2.5-MHz probe. All images were
digitally stored and later analyzed offline. We measured the LV
end-systolic and end-diastolic volumes and calculated the LV ejection
fraction (LVEF) using the Simpson biplane method. Mitral E and A peak
velocities were measured to determine the ratio of early-diastolic LV
inflow velocity to atrial-systolic velocity (E/A). Furthermore, we
obtained the average tissue Doppler-derived early diastolic mitral
annular velocity (e’) from measurements taken at both the septal and
lateral sides of the mitral annulus. We calculated the average ratio of
early-diastolic LV inflow velocity to early-diastolic mitral annular
velocity (E/e’).
Using two-dimensional speckle tracking echocardiography, myocardial
deformation analysis (LV GLS) was performed in this study.
Echocardiographic images were acquired at a frame rate of 50-70 frames
per second (with individual adjustments made for optimal analysis). A
digital loop was acquired from three apical views, including four-,
two-, and three-chamber views. For LV GLS analysis, after manually
selecting the cardiac cycle, the LV endocardial border was manually
traced at the end-systolic frame. The GLS was calculated by averaging
the mean values of all valid segments obtained from the speckle tracking
analysis.
LAAWV was assessed using transthoracic tissue Doppler echocardiography
(TDE). To obtain the LAAWV, we first identified the triangle-shaped left
atrial appendage (LAA) on the left side of the aortic root in the
parasternal short-axis view. Then, a sample volume was placed very close
to the tip of the LAA, and the LAAWV was measured using pulsed
transthoracic TDE. LAWV, specifically defined as LAA peak wall velocity,
was measured using Doppler tissue imaging (DTI) with the sample volume
of pulsed-wave Doppler positioned on the LAA tip, as previously
reported. LAAWV was calculated by averaging the maximum negative peak
wave velocity within each RR interval over 10 cardiac cycles, excluding
the signals from the mitral ring motion. To ensure accuracy, the Doppler
beam angle was corrected by observing the direction of the
longitudinally contracting LAA. Additionally, the left atrial (LA)
dimension was conventionally measured using M-mode transthoracic
echocardiography.