Methods
We enrolled patients affected by CHF who were referred to the Heart Failure Outpatients Clinic of the Cardiology Unit of the Polyclinic University Hospital Riuniti of Foggia, Italy, between October 2020 and January 2023. All the patients were enrolled in the Daunia registry, which was approved by the Institutional Ethics Committee of the Polyclinic University Hospital of Foggia, Italy (Protocol Code 68/CE/20, approved on 26 May 2020), and all provided written informed consent to participate.
The following inclusion criteria were considered: history of heart failure of any origin with recommended medical therapy at the time of the enrolment and in clinically stable condition for at least 30 days (e.g. no significant changes in hemodynamic status or medical therapy). Patients diagnosed with atrial fibrillation were enrolled if a regular ventricular paced rhythm was present, whereas they were excluded if an irregular rhythm was observed.
At the time of enrolment, each participant underwent a medical evaluation, including an electrocardiogram (ECG) and two-dimensional echocardiography.
Medical examination and electrocardiogram. Each participant’s full medical history was collected. A physical examination and a 12-lead ECG were performed. Any evidence of ischemic cardiomyopathy, arterial hypertension, atrial fibrillation, diabetes mellitus, and/or dyslipidaemia was documented together with any history of chronic kidney disease and dialysis. New York Heart Association (NYHA) classes, anthropometric data, systolic and diastolic arterial pressures, and heart rhythms were also recorded. If available, the most recent routine blood chemistries were also documented. In particular, by serum creatinine, the glomerular filtration rate was calculated using the abbreviated CKD-EPI formula (GFR-EPI, ml/min/1.73 m2) [8].
Echocardiographic evaluation. Two-dimensional echocardiographic imaging and Doppler acquisition were performed using an EPIQ CVx system (Philips, Amsterdam, the Netherlands) with an S5-1 transducer. At the baseline, five cycles of ECG-guided standard parasternal long- and short-axis, apical two-, three-, and four-chamber, and subcostal views were acquired. The LV end-diastolic diameter (LVEDD) and interventricular septum and LV posterior wall thicknesses were measured; the LV mass indexed for body surface area was calculated based on current recommendations [9]. Additionally, to analyse the tricuspid annular plane systolic excursion, an RV-focused four-chamber view was obtained. The LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), and LV ejection fraction (LVEF) were calculated using Simpson’s rule. The LA volume was also calculated using Simpson’s rule and indexed for body surface area (LAVI). Using colour Doppler, mitral (MR) and tricuspid (TR) regurgitation were evaluated semi-quantitatively and assigned arbitrary units ranging from 0 to 4. The maximum trans-tricuspid valve pressure gradient was assessed using continuous-wave Doppler. Pulmonary systolic arterial pressure (PASP) was estimated based on the vena cava diameter. Peaks of early wave velocity at the mitral valve (E) were measured using pulsed Doppler. Furthermore, the early diastolic velocity peaks (e’) at the level of the septal (e’s) and lateral (e’l) mitral annulus were measured using pulsed and tissue Doppler imaging (TDI) [9]. Then the means of e’s and e’l (e’m) as well as the ratios between E and e’s (Ee’s) and E and e’m (Ee’m) were calculated.
The AutoStrain application of the Philips EPIQ CVx ultrasound systems was used for the ‘off-cart’ analysis of strain from stored examinations. Values for LV global longitudinal strain (LV-GLS) were obtained from the analysis of two-, three-, and four-chamber views. The software automatically generated curves representing longitudinal strain; LV-GLS was calculated by averaging values obtained in all the segments. In this study, reduced systolic strain is indicated by values that are less negative than those determined at the baseline. The global longitudinal strain of the right ventricle (RVGLS) and that of the free wall (RVfwLS) were also calculated automatically from the values obtained in an RV-focused four-chamber view. In this study, reduced ventricular systolic strain is indicated by values that are less negative than those determined at the baseline.
By the standard four-chamber view, the AutoStrain application of the Philips EPIQ CVx ultrasound systems was also used for the ‘off-cart’ analysis of LA strain from stored examinations. As shown in Figure 1, the LA strain of reservoir (LAr), including those ofconduit (LAcd) and contraction (LAct), were calculated (D.D., E.T.). Finally, the ratios between LAr and E/e’s (LAr/Ees) and LAr and E/e’l (LAR/Eel) and that between LAr and E/e’m (LAr/Eem) were evaluated [7].