773 Correlation between high troponin levels and left atrial strain as biomarker of incremented atrial fibrillation rate in patients with acute myocardial infarction
Authors: De Luca Emilia , Madeo Andrea , Pasquale Giovanni San , Ponturo Gianluca , Rosselli Francescantonio , De Bonis Silvana , Bisignani Giovanni 
Published: December 2021

Abstract

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.