Impact of Multi-parametric Analyses on Normal Left Atrial Strain by Cardiovascular Magnetic Resonance Feature Tracking

Left-atrial (LA) strain is the result of complex hemodynamics, increasingly assessed by feature-tracking cardiovascular magnetic resonance (CMR). We investigate the value of multi-parametric regression (MPR) analyses and the influence of the heart rate on LA-strain. As LA-strain data remains limited, CMR-quantified sex- and age-dependent normal values were derived. After following a health assessment questionnaire, 183 healthy volunteers (11-70 years, 97 females, median 32.9±28.3 years) were recruited for LA-strain assessment. LA volumetric data, left ventricular strain, transmitral and pulmonary venous blood flow parameters were utilized to create clusters for MPR analyses for all subjects and heart rate-specific subgroups (range: 60–75 beats-per-minute, N=106). In comparison to the total cohort, subgroups showed no gender differences (p>0.05) for LA reservoir, conduit and booster strains (all: 47.3±12.7%; 29.0±15.5%; 17.6±5.4%) and strain rates (all: 2.1±1.0 s−1; -2.9 ± 1.5 s−1; -2.3 ± 1.0 s−1). MPR analyses identified parameter clusters with large effect size (|R²|≥0.26) for reservoir-, conduit- and booster strain and corresponding active and passive cardiac functional parameters. Increased correlations for the subgroup were found. In contrast to previous studies, heart rate selected subgroups showed no gender differences in LA-strain. MPR analyses improve characterization of LA-strain at selected heart rates.

Changes in left atrial function in patients undergoing cardioversion for atrial fibrillation: relevance of left atrial strain in heart failure

Background Left atrial (LA) reservoir strain provides prognostic information in patients with and without heart failure (HF), but might be altered by atrial fibrillation (AF). The aim of the current study was to investigate changes of LA deformation in patients undergoing cardioversion (CV) for first-time diagnosis of AF. Methods and results We performed 3D-echocardiography and strain analysis before CV (Baseline), after 25 ± 10 days (FU-1) and after 190 ± 20 days (FU-2). LA volumes, reservoir, conduit and active function were measured. In total, 51 patients were included of whom 35 were in SR at FU-1 (12 HF and preserved ejection fraction (HFpEF)), while 16 had ongoing recurrence of AF (9 HFpEF). LA maximum volume was unaffected by cardioversion (Baseline vs. FU-2: 41 ± 11 vs 40 ± 10 ml/m2; p = 0.85). Restored SR led to a significant increase in LA reservoir strain (Baseline vs FU-1: 12.9 ± 6.8 vs 24.6 ± 9.4, p < 0.0001), mediated by restored LA active strain (SR group Baseline vs. FU-1: 0 ± 0 vs. 12.3 ± 5.3%, p < 0.0001), while LA conduit strain remained unchanged (Baseline vs. FU-1: 12.9 ± 6.8 vs 13.1 ± 6.2, p = 0.78). Age-controlled LA active strain remained the only significant predictor of LA reservoir strain on multivariable analysis (β 1.2, CI 1.04–1.4, p < 0.0001). HFpEF patients exhibited a significant increase in LA active (8.2 ± 4.3 vs 12.2 ± 6.6%, p = 0.004) and reservoir strain (18.3 ± 5.7 vs. 22.8 ± 8.8, p = 0.04) between FU-1 and FU-2, associated with improved LV filling (r = 0.77, p = 0.005). Conclusion Reestablished SR improves LA reservoir strain by restoring LA active strain. Despite prolonged atrial stunning following CV, preserved SR might be of hemodynamic and prognostic benefit in HFpEF. Graphical abstract

Characteristics of left atrial strain in patients with atrial fibrillatio after cardioversion

The aim of the study – to evaluate the parameters of left atrial myocardial strain in patients with atrial fibrillation who underwent electrical and drug cardioversion.Materials and methods. The study included 118 patients of the University Clinical Hospital No 1 of the First Sechenov Moscow State Medical University. The analysis was carried out in three groups of patients: group 1 (n=54) – patients with atrial fibrillation who underwent electrical cardioversion; group 2 (n=31) – patients with atrial fibrillation who underwent drug cardioversion; group 3 (n=43) – patients without a history of atrial fibrillation. The clinical and anamnestic data of the medical history of each patient, as well as ultrasound indicators were evaluated: global strain of the left atrial, the values of negative peaks as a reflection of the left atrial systole and the values of positive peaks as a reflection of the filling of the left atrium, LASI – the left atrial stiffness index.Results. The analysis showed that left atrial strain in patients with atrial fibrillation were reduced in all analyzed parameters: negative strain peaks (-9.00 vs. -12.6 in the control group, p<0.001), positive strain peaks (12.6 vs. 14.6 in the control group, p<0.001), global left atrial strain (21.5 in the atrial fibrillation group vs. 27.3 in the control group, p<0.001). Left Atrial Stiffness Index (LASI) was significantly higher in patients with a stopped episode of atrial fibrillation (0.50 vs. 0.40, p=0.006).Conclusions. The indicators of left atrial strain were significantly reduced, and the left atrial stiffness index was significantly increased both in the group with electrical cardioversion and in the group with drug-induced cardioversion, compared with patients with similar cardiovascular pathologies, but without a history of atrial fibrillation episodes.

773 Correlation between high troponin levels and left atrial strain as biomarker of incremented atrial fibrillation rate in patients with acute myocardial infarction

Aims Heart rhythm disorders, both bradyarrhythmias and tachyarrhythmias, are the most frequently observed complication in the acute phase and after primary angioplasty in patients with acute myocardial infarction (AMI). New onset atrial fibrillation (Afib) represents the most frequent arrhythmia found between 6% and 21% in patients with AMI and its onset increases the thromboembolic and mortality risk of all causes of those patients. Troponin levels measured with modern assays represent today the most specific cardiac biomarker of myocardial injury and its measurement represents the cornerstone for the diagnosis of AMI in accordance with the ESC Guidelines 2018; however, also Afib itself causes an increase in troponin values (troponinopathy). Therefore, the single biohumoral value cannot assume prognostic value in helping the clinician to recognize patients with AMI who are more predisposed to encounter Afib. So, the object of our evaluation was to support the elevated troponin values with echocardiographic biomarkers, such as the evaluation of the left atrial strain (LAS), to perform a more accurate stratification of the arrhythmic risk in patients with AMI. Methods and results A prospective multiparametric study was carried out at our Interventional Cardiology Hub Center. 240 patients with ACS-STEMI diagnosed were recruited over one year from March 2020 to March 2021. Patients included were all ≥18 (55 ± 23 y), predominantly male (88% male, 12% female). Exclusion criteria were: permanent atrial fibrillation; valvular heart disease (moderate or severe heart valve stenosis or valve replacement); implantation of a pacemaker or defibrillator; (4) poor image quality. Emergency coronary angiography (CAG) was carried out to execute primary percutaneous intervention (primary PCI with DES) on the culprit vessel. All patients underwent echocardiography by GE Vivid 80 (GE Ultrasound, Horten, Norway) in order to evaluate changes in segmental kinetics, left ventricular ejection fraction (LVEF). The ratio of peak early filling velocity of mitral inflow to early diastolic annulus velocity (E′) of the medial annulus (E/E′) was calculated. Left atrial volumes (LAVi, ml/m2) and diameter were obtained through standard apical 4 and 2 chamber views with a frame-rate range of 40–71 frames/s; then, offline analysis of images was performed using EchoPAC version 201 (GE Vingmed Ultrasound) (VSSLV) software in order to calculate LAS for each one. Patients were subjected to serial sampling to evaluate temporally troponin values and the possible Afib appearance was recognized by telemetry monitoring. Statistical analysis was performed using SPSS version 20 (IBM, Armonk, New York), continuous variables were expressed as mean ± standard deviation (SD). Pearson’s correlation coefficient was used to assess the correlation between strain value, baseline characteristics and troponin levels. All statistical tests are two-sided, and a P-value &lt; 0.05 is considered statistically significant. Two groups were recognized: high troponin levels with pathological LAS and new Afib (N = 47); medium-high troponin levels with normal LAS and no Afib (N = 143). Respectively, LAS were 8.4 ± 4.0% vs. 16 ± 4.5%, P &lt; 0.001, LAVi 44 ± 5 ml/m2 vs. 30 ± 3.2, P = 0.001, and peak of troponin levels (3.45 ± 0.46 ng/ml vs. 2.34 ± 0.22 ng/ml, P = 0.002). Multivariate analysis identified that peak troponin levels alone wasn’t a prognostic index of increased arrhythmic burden, while the correlation between high peak levels and altered LAS were independent predictors of new AFib in AMI. Conclusions The evaluation of atrial dysfunction by new echo-derived parameters and its correlation with troponin values allows a more accurate stratification of arrhythmic risk in patients with ACS. The applicability of the obtained data would allow a more careful evaluation of the clinical trend and the prognostic outcome in the subcategory analysed. Therefore, the association between biohumoral and instrumental parameters could become new biomarkers capable of predicting an increase in thromboembolic risk in AMI patients. The creation of an app that takes into account the parameters listed could be a possible future support that can help the clinician calculate the increased risk rate of new Afib in patients with ACS.