Phonon replicas lineshape in GaN epilayers: The A and B exciton contributions

A thorough investigation of the lineshape of phonon-assisted emission in a high-quality c-plane GaN epilayer is presented up to 200K. Before addressing the lineshape analysis, we corrected distortions in the phonon replica spectra due to etaloning effects, by performing photoluminescence and reflectivity measurements. The comparison with existing models for phonon replicas shows that the commonly adopted description of the exciton-phonon interaction involving a single excitonic band leads to a large discrepancy with the experimental data. Only the consideration of the complex nature of the excitonic band in GaN, including A and B exciton contributions, allows accounting for the temperature dependence of phonon replicas lineshape

Sports cardiology: A glorious past, a well-defined present, a bright future

The attention towards sports cardiology has dramatically grown after the introduction of preparticipation screening and the need for specific education on electrocardiogram interpretation in athletes, given the differences between athletes and the general population. The present article stresses the need for specific skills, knowledge, and clinical expertise in sports cardiology, which are essential for appropriately screening competitive athletes to prevent sudden cardiac death and avoid overdiagnosis. However, disqualification from sports competitions may lead to sports inactivity, and athletes may enter a gray zone where little or no information is provided about what they can or cannot do to stay active. However, modern sports cardiology cannot neglect the patient's needs and the importance of the safe practice of regular exercise. In this context, the personalized exercise prescription plays a crucial role in the core curriculum and the clinical activity of professionals involved in sports cardiology programs. Given its specificities, sports cardiology requires a formal education plan for medical school students and all residents. Additional education and practice are required for young colleagues who want to focus their professional lives on sports cardiology. The future directions of emerging modern sports cardiology should not neglect the importance of a scientific community that works together, designing multicenter international outcomes-based research to address the many remaining areas of uncertainty

Large K-exciton dynamics in GaN epilayers: the non-thermal and thermal regime

We present a detailed investigation concerning the exciton dynamics in GaN epilayers grown on c-plane sapphire substrates, focussing on the exciton formation and the transition from the nonthermal to the thermal regime. The time-resolved kinetics of LO-phonon replicas is used to address the energy relaxation in the excitonic band. From ps time-resolved spectra we bring evidence for a long lasting non-thermal excitonic distribution which accounts for the rst 50 ps. Such a behavior is con rmed in di erent experimental conditions, both when non-resonant and resonant excitation are used. At low excitation power density the exciton formation and their subsequent thermalization is dominated by impurity scattering rather than by acoustic phonon scattering. The estimate of the average energy of the excitons as a function of delay after the excitation pulse provides information on the relaxation time, which describes the evolution of the exciton population to the thermal regime.Comment: 9 pages,8 figure

Reproducibility of ventricular arrhythmias at exercise testing for prediction of non-ischaemic left ventricular scar in athletes

Aims The non-ischaemic left ventricular scar (NILVS) is an emerging substrate of ventricular arrhythmias (VA) in the athlete. We tested the diagnostic value of VA reproducibility at repeated exercise testing (ET). Methods We included consecutive athletes who underwent cardiac magnetic resonance (CMR) for evaluation of VA and two con- and results secutive ET off-therapy within 12 months. Those with a positive family history of premature sudden death/cardiomyopathy, syncope/pre-syncope, ECG or echocardiography abnormalities, or low-risk VA (exercise-suppressed infundibular or fascicular VA) were excluded. The NILVS was defined as subepicardial/midmyocardial stria of late gadolinium enhancement involving >5% of the LV mass. Reproducibility was defined as the occurrence of VA with the same pattern and behaviour during repeated ET. Of 325 athletes who underwent CMR for evaluation of VA, 75 were included, and 30 showed NILVS involving three [2–4] LV segments. At first ET, athletes with NILVS showed a higher prevalence of exercise-induced VA (93% vs. 53%, P < 0.001), while other VA characteristics did not differ between groups. At repeated ET, reproducibility was observed in 97% of athletes with vs. 13% without NILVS (P < 0.001). The remaining 87% of athletes with normal CMR either did not show any VA at repeated ET (59%) or showed arrhythmias with different patterns, mostly infundibular. Reproducibility yielded a positive predictive value for NILVS of 83% and a negative predictive value of 98%. Conclusion VA reproducibility at repeated ET predicted an underlying NILVS in athletes with VA and otherwise normal clinical workup. This finding may improve risk stratification and appropriate CMR referral of athletes with apparently idiopathic VA

P2316Outcome of septal reduction therapies for obstructive hypertrophic cardiomyopathy in a high-flow referral centre with moderate volume procedural programmes

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Tricuspid Regurgitation Velocity and Mean Pressure Gradient for the Prediction of Pulmonary Hypertension According to the New Hemodynamic Definition

Background: The hemodynamic definition of PH has recently been revised with unchanged threshold of peak tricuspid regurgitation velocity (TRV). The aim of this study was to evaluate the predictive accuracy of peak TRV for PH based on the new (>20 mmHg) and the old (>25 mmHg) cut-off value for mean pulmonary artery pressure (mPAP) and to compare it with the mean right ventricular–right atrial (RV–RA) pressure gradient. Methods: Patients with advanced heart failure were screened from 2016 to 2021. The exclusion criteria were absent right heart catheterization (RHC) results, chronic obstructive pulmonary disease, any septal defect, inadequate acoustic window or undetectable TR. The mean RV–RA gradient was calculated from the velocity–time integral of TR. Results: The study included 41 patients; 34 (82.9%) had mPAP > 20 mmHg and 24 (58.5%) had mPAP > 25 mmHg. The AUC for the prediction of PH with mPAP > 20 mmHg was 0.855 for peak TRV and mean RV–RA gradient was 0.811. AUC for the prediction of PH defined as mPAP > 25 mmHg for peak TRV was 0.860 and for mean RV–RA gradient was 0.830. A cutoff value of 2.4 m/s for peak TRV had 65% sensitivity and 100% positive predictive value for predicting PH according to the new definition. Conclusions: Peak TRV performed better than mean RV–RA pressure gradient in predicting PH irrespective of hemodynamic definitions. Peak TRV performed similarly with the two definitions of PH, but a lower cutoff value had higher sensitivity and equal positive predictive value for PH

Athlete’s heart: a cardiovascular step-by-step multimodality approach

“Athlete’s heart” is a spectrum of morphological, functional, and regulatory changes that occur in people who practice regular and long-term intense physical activity. The morphological characteristics of the athlete’s heart may overlap with some structural and electrical cardiac diseases that may predispose to sudden cardiac death, including inherited and acquired cardiomyopathies, aortopathies and channelopathies. Overdiagnosis should be avoided, while an early identification of underlying cardiac life-threatening disorders is essential to reduce the potential for sudden cardiac death. A step-by-step multimodality approach, including a first-line evaluation with personal and family history, clinical evaluation, 12-lead resting electrocardiography (ECG), followed by second and third-line investigations, as appropriate, including exercise testing, resting and exercise echocardiography, 24-hour ECG Holter monitoring, cardiac magnetic resonance, computed tomography, nuclear scintigraphy, or genetic testing, can be determinant to differentiate between extreme physiology adaptations and cardiac pathology. In this context, cardiovascular imaging plays a key role in detecting structural abnormalities in athletes who fall into the grey zone between physiological adaptations and a covert or early phenotype of cardiovascular disease

The role of echocardiography in sports cardiology: An expert opinion statement of the Italian Society of Sports Cardiology (SIC sport)

Transthoracic echocardiography (TTE) is routinely required during pre-participation screening in the presence of symptoms, family history of sudden cardiac death or cardiomyopathies <40-year-old, murmurs, abnormal ECG findings or in the follow-up of athletes with a history of cardiovascular disease (CVD). TTE is a cost-effective first-line imaging modality to evaluate the cardiac remodeling due to long-term, intense training, previously known as the athlete's heart, and to rule out the presence of conditions at risk of sudden cardiac death, including cardiomyopathies, coronary artery anomalies, congenital, aortic and heart valve diseases. Moreover, TTE is useful for distinguishing physiological cardiac adaptations during intense exercise from pathological behavior due to an underlying CVD. In this expert opinion statement endorsed by the Italian Society of Sports Cardiology, we discussed common clinical scenarios where a TTE is required and conditions falling in the grey zone between the athlete's heart and underlying cardiomyopathies or other CVD. In addition, we propose a minimum dataset that should be included in the report for the most common indications of TTE in sports cardiology clinical practice

Sport PRactice and its Effects on aortic size and valve function in bicuspid Aortic valve Disease: a cross-sectional report from the SPREAD study

Objective: Concerns exist about the possible detrimental effects of exercise training on aortic size and valve function in individuals with bicuspid aortic valve (BAV). This multicentre international study aimed to determine the characteristics of aortic size and valve function in athletes versus non-athletes with BAV and athletes with tricuspid aortic valve (TAV). Methods: We enrolled competitive athletes with BAV and age- and sex-matched athletes with TAV and non-athletes with BAV. We assessed valve function, aortic size and biventricular measures using echocardiography. Individuals with established moderate-severe AV stenosis, regurgitation or significant aortic dilation were excluded from the study. Results: The study population comprised 504 participants: 186 competitive athletes with BAV (84% males; age 30±11 years), 193 competitive athletes with TAV and 125 non-athletes with BAV. The aortic annulus was greater in athletes with BAV than athletes with TAV and non-athletes with BAV (p<0.001). Both athletic and non-athletic individuals with BAV had greater sinuses of Valsalva, sino-tubular junction and ascending aorta diameters than athletes with TAV (p<0.001). However, no significant differences were found between athletes and non-athletes with BAV. Left ventricular index volumes and mass were greater in athletes with BAV than in the other two groups (p<0.001). Individuals with BAV (athletes and non-athletes) had greater mean gradients than TAV athletes. Conclusion: This multicentre international study demonstrates no differences between athletes with BAV and non-athletes with BAV regarding aortic valve function or aortic dimensions. However, athletes with BAV have larger aortic diameters and a relatively worse valvular function than athletes with TAV