Marco Solari

Novel echocardiographic techniques for the evaluation of athletes’ heart: A focus on speckle-tracking echocardiography

Background The development and rapid dissemination of two-dimensional echocardiography led to important further advances in our understanding of athletes’ heart that has been the subject of several echocardiographic studies involving many thousands of athletes. The description of ventricular chamber enlargement, myocardial hypertrophy and atrial dilatation has led to a more comprehensive understanding of cardiac adaptation to exercise conditioning. Most recently, advanced echocardiographic techniques have begun to clarify significant functional adaptations of the myocardium that accompany previously reported morphological features of athletes’ heart. In particular, speckle-tracking echocardiography (STE) has recently provided further insights into the characterisation of myocardial properties. Discussion STE is a relatively new, largely angle-independent, non-invasive imaging technique that allows for an objective and quantitative evaluation of global and regional myocardial function. STE has enhanced our understanding of athletes’ heart through a comprehensive characterisation of biventricular and biatrial function, providing novel insights into the investigation of physiological adaptation of the heart to exercise conditioning. These peculiarities can provide further useful data to distinguish between athletes’ heart and cardiomyopathies. Furthermore, STE represents a promising tool to address new concerns on right ventricular function and to increase understanding of the complexity of the non-systemic circulation, especially in the athletic population. Conclusion This review article analyses new data on cardiac function in athletes by novel echocardiographic techniques with a particular attention to the application of STE to characterise biventricular and biatrial function in athletes.

Echocardiographic assessment of left ventricular systolic function: from ejection fraction to torsion

Assessment of left ventricular (LV) systolic function is the cornerstone of the echocardiographic examination. There are many echocardiographic parameters that can be used for clinical and research purposes, each one with its pros and cons. The LV ejection fraction is the most used one due to its feasibility and predictability, but it also has many limits, related to both the imaging technique used for calculation and to the definition itself. LV longitudinal function is expression of subendocardial fibers contraction. Because the subendocardium is often involved early in many pathological processes, its analysis has been a fertile field for the development of sensitive parameters. Longitudinal function can be evaluated in many ways, such as M-mode echocardiography, tissue Doppler imaging, and speckle tracking echocardiography. This latter is a relatively new tool to assess LV function through measurement of myocardial strain, with a high temporal and spatial resolution and a better inter- and intra-observer reproducibility compared to Doppler strain. It is angle independent, not affected by translation cardiac movements, and can assess simultaneously the entire myocardium along all the three-dimensional geometrical (longitudinal, circumferential, and radial) axes. Speckle tracking echocardiography also allows the analysis of LV torsion. The aim of this paper was to review the main echocardiographic parameters of LV systolic function and to describe its pros and cons.

Effects of training on LV strain in competitive athletes

Objective LV longitudinal strain, a recognised marker of LV function, has been recently applied to the evaluation of the athletes heart. At present, little is known about the influence of training on LV global longitudinal strain (GLS) in athletes. The aim of this study was to prospectively investigate the impact of training on LV longitudinal strain and twist mechanics in a cohort of competitive athletes. Methods Ninety-one competitive athletes, practising team sports and competing at national or international level, were analysed. Echocardiographic evaluation was performed at the beginning of the season (low training) and after 18±2 weeks of a supervised, intensive training programme (peak training). Results A significant increase in LV mass (p<0.0001), LV end-diastolic and end-systolic volume (p=0.0001 and <0.0001, respectively) was found at peak training. LV basal and apical torsion (p=0.59 and 0.43, respectively) and LV twisting (p=0.78) did not change, and only a mild increase in LV GLS was evident after training (p=0.044). Resting heart rate was identified as the only independent predictor of LV GLS after training (β=0.30, p=0.005). Conclusions A 18-week, intensive training programme induced only a slight increase in LV GLS despite marked changes in cardiac morphology, suggesting a physiological adaptation of the LV to exercise conditioning.

Normative Reference Values of Right Heart in Competitive Athletes: A Systematic Review and Meta-Analysis

Training-induced right ventricular (RV) enlargement is frequent in athletes. Unfortunately, RV dilatation is also a common phenotypic expression and one of the diagnostic criteria of arrhythmogenic RV cardiomyopathy (ARVC). The current echocardiographic reference values derived from the general population can overestimate the presence of RV dilatation in athletes. We performed a meta-analysis of the literature to derive the proper reference values for assessing RV enlargement in competitive athletes. We conducted systematic review of English-language studies in the MEDLINE, Scopus, and Cochrane databases investigating RV size and function by echocardiography and by cardiac magnetic resonance (CMR) in competitive athletes. In total, 6,806 and 740 competitive athletes were included for the echocardiographic and CMR quantification of the RV, respectively. In this review, we present normal reference values for RV size and function to be applied in competitive athletes according to the disciplines practiced. The reference ranges reported in this review suggest that physicians should be aware that application of the current recommendations for normal population could be misleading when evaluating athletes. We suggest using these normative reference values, obtained in competitive athletes, to avoid the potential for mistakenly concluding, in this specific population, that RV size or function are abnormal.

Atrial chamber remodelling in healthy pre-adolescent athletes engaged in endurance sports: A study with a longitudinal design. The CHILD study

AIMS Previous studies investigated the exercise-induced adaptation of left (LA) and right atrium (RA) in adults, but little is known about respective changes in the growing heart of children. We aimed to longitudinally investigate the effects of endurance training on biatrial remodelling in preadolescent athletes. METHODS AND RESULTS Ninety-four children (57 endurance athletes, 37 sedentary controls; mean age 10.8±0.2 and 10.2±0.2years, respectively) were evaluated at baseline and after 5months by ECG and by two-dimensional, three-dimensional (3D) and speckle-tracking echocardiography. Athletes were trained at least 10h/week. The resting heart rate was lower in athletes (p=0.046) and decreased further after training (p<0.0001). Neither athletes nor controls had ECG evidence for LA or RA enlargement. At baseline, indexed LA volumes did not differ between groups (p=0.14) but indexed RA dimensions were larger in athletes (p=0.007). After 5months, indexed LA volumes increased in athletes but not in controls (p<0.0001, p=0.29; respectively) while indexed RA volumes increased in both groups (p<0.0001, p=0.018; respectively). At the same time, slight differences in biatrial reservoir and contractile function were found either in athletes, as demonstrated by speckle-tracking echocardiography, but 3D-derived LA and RA ejection fraction remained stable in both groups. CONCLUSION Endurance training influences the growing heart of preadolescent athletes with an additive increase in biatrial size, suggesting that morphological adaptations can occur also in the early phases of the sports career. Training-induced remodelling was associated with a preserved biatrial function, supporting the hypothesis of a physiological remodelling.

Two-dimensional and three-dimensional left ventricular deformation analysis: a study in competitive athletes.

Two-dimensional (2D) speckle-tracking echocardiography (STE) has clarified functional adaptations accompanying the morphological features of ‘athlete’s heart’. However, 2D STE has some limitations, potentially overcome by three-dimensional (3D) STE. Unfortunately, discrepancies between 2D- and 3D STE have been described. We therefore sought to evaluate whether dimensional and functional differences exist between athletes and controls and whether 2D and 3D left ventricular (LV) strains differ in athletes. One hundred sixty-one individuals (91 athletes, 70 controls) were analysed. Athletes were members of professional sports teams. 2D and 3D echocardiography and STE were used to assess LV size and function. Bland–Altman analysis was used to estimate the level of agreement between 2D and 3D STE. Athletes had greater 2D and 3D-derived LV dimensions and LV mass (p < 0.0001 for all), while 2D- and 3D-derived LV ejection fraction did not differ as compared with controls (p = 0.82 and p = 0.89, respectively). Longitudinal, radial, and circumferential strains did not differ between athletes and controls, neither by 2D nor by 3D STE. Three-dimensional longitudinal and circumferential strain values were lower (p < 0.0001 for both) while 3D radial strain was greater, as compared with 2D STE (p < 0.001). Bland–Altman plots demonstrated the presence of an absolute systematic error between 2D and 3D STE to analyse LV myocardial deformation. 3D STE is a useful and feasible technique for the assessment of myocardial deformation with the potential to overcome the limitations of 2D imaging. However, discrepancies exist between 2D and 3D-derived strain suggesting that 2D and 3D STE are not interchangeable.

Systematic Left Ventricular Assist Device Implant Eligibility with Non-Invasive Assessment: The SIENA Protocol

In patients with end-stage left ventricular (LV) heart failure who receive LV assist device (LVAD) implantation, right ventricular (RV) failure represents a possible critical complication that heavily affects morbidity and mortality. Several clinical, laboratory, hemodynamic, and echocardiographic variables have been found to be associated with RV failure occurrence after surgery. Different models and risk scores have been proposed, with poor results. No accordance has ever been reached about RV pre-operative evaluation, and time has come to introduce a standardized systematic protocol for LVAD suitability assessment according to RV function. We analyzed imaging parameters associated with LVAD implantation-related RV failure, in order to identify the minimum number for pre-operative reliable prediction of post-operative RV failure. A few echocardiographic parameters have been identified as the most reliable, or promising, and reproducible tools in this field: free-wall RV longitudinal strain, RV fractional area change, RV sphericity index, and RV ejection fraction with 3D-echocardiography. We propose the Systematic LVAD Implant Eligibility with Non-invasive Assessment protocol–the SIENA protocol–as a new and simple way of pre-operative evaluation of patients candidates to LVAD implantation.