T-Wave Alternans Measured by 24-Hour Ambulatory Recordings Rather Than Exercise Stress Tests as a Risk Stratification Marker in Patients With Long QT Syndrome.

BACKGROUND: Few small-sample studies have quantified the T-wave alternans (TWA) value by 24-hour ambulatory recordings or exercise stress tests in patients with long QT syndrome (LQTS). The cutoff point of TWA ≥47 µV was based on patients with myocardial infarction. In our study, we aimed to (1) evaluate the association of TWA with life-threatening arrhythmic events (LAEs); (2) compare the predictive model of LAEs according to the TWA value measured by 24-hour ambulatory recordings and exercise stress tests; and (3) propose a cutoff point for the high risk of LAEs in patients with LQTS. METHODS AND RESULTS: The study cohort included 110 patients with LQTS referred to our hospital, and the primary outcome was LAEs. Thirty-one patients with LQTS (31/110 [28.2%]) developed LAEs during the following 24 (12-47) months. Peak TWA value quantified from 12 leads by 24-hour ambulatory recordings in patients with LQTS with LAEs (LQTS-LAEs group) was significantly higher than LQTS without LAEs (LQTS-non-LAEs group) (64.0 [42.0-86.0] µV versus 43.0 [36.0-53.0] µV; P<0.01). There was no statistical difference in TWA value measured by exercise stress tests between the 2 groups (69.0 [54.5-127.5] µV versus 68.5 [53.3-99.8] µV; P=0.871). The new cutoff point of the peak TWA value measured by 24-hour ambulatory recordings was 55.5 µV, with a sensitivity of 75.0% and a specificity of 78.6%. A univariate Cox regression analysis revealed that TWA value ≥55.5 µV was a strong predictor of LAEs (hazard ratio [HR], 4.5 [2.1-9.6]; P<0.001]. A multivariate Cox regression analysis indicated that TWA value ≥55.5 µV remained significant (HR, 2.7 [1.1-6.8]; P=0.034). CONCLUSIONS: Peak TWA measured by 24-hour ambulatory recordings was a more favorable risk stratification marker than exercise stress tests for patients with LQTS.

Critical evaluation of artificial intelligence as a digital twin of pathologists for prostate cancer pathology.

Prostate cancer pathology plays a crucial role in clinical management but is time-consuming. Artificial intelligence (AI) shows promise in detecting prostate cancer and grading patterns. We tested an AI-based digital twin of a pathologist, vPatho, on 2603 histological images of prostate tissue stained with hematoxylin and eosin. We analyzed various factors influencing tumor grade discordance between the vPatho system and six human pathologists. Our results demonstrated that vPatho achieved comparable performance in prostate cancer detection and tumor volume estimation, as reported in the literature. The concordance levels between vPatho and human pathologists were examined. Notably, moderate to substantial agreement was observed in identifying complementary histological features such as ductal, cribriform, nerve, blood vessel, and lymphocyte infiltration. However, concordance in tumor grading decreased when applied to prostatectomy specimens (κ = 0.44) compared to biopsy cores (κ = 0.70). Adjusting the decision threshold for the secondary Gleason pattern from 5 to 10% improved the concordance level between pathologists and vPatho for tumor grading on prostatectomy specimens (κ from 0.44 to 0.64). Potential causes of grade discordance included the vertical extent of tumors toward the prostate boundary and the proportions of slides with prostate cancer. Gleason pattern 4 was particularly associated with this population. Notably, the grade according to vPatho was not specific to any of the six pathologists involved in routine clinical grading. In conclusion, our study highlights the potential utility of AI in developing a digital twin for a pathologist. This approach can help uncover limitations in AI adoption and the practical application of the current grading system for prostate cancer pathology.

Study of the Durability of Membrane Electrode Assemblies in Various Accelerated Stress Tests for Proton-Exchange Membrane Water Electrolysis.

In this work, we focus on the degradation of membrane electrode assemblies (MEAs) in proton-exchange membrane water electrolysis (PEMWE) induced by different accelerated stress tests (ASTs), including constant-current mode, square-wave mode, and solar photovoltaic mode. In constant-current mode, at continuous testing for 600 h at 80 °C, a degradation of operating voltage increased by the enhanced current density from 22 µV/h (1 A/cm2) to 50 µV/h (3 A/cm2). In square-wave mode, we found that in the narrow fluctuation range (1-2 A/cm2), the shorter step time (2 s) generates a higher degradation rate of operating voltage, but in the wide fluctuation range (1-3 A/cm2), the longer step time (22 s) induces a faster operating voltage rise. In the solar photovoltaic mode, we used a simulation of 11 h sunshine duration containing multiple constant-current and square-wave modes, which is closest to the actual application environment. Over 1400 h ASTs, the solar photovoltaic mode lead to the most serious voltage rise of 87.7 µV/h. These results are beneficial to understanding the durability of the PEM electrolyzer and optimizing the components of MEAs, such as catalysts, membranes, and gas diffusion layers.

Las ecuaciones predictoras de frecuencia cardiaca máxima no superan prueba clave de validación externa / Maximum heart rate prediction equations fail key external validation test / Equações de predição da frequência cardíaca máxima não superam teste-chave de validação externa

Resumen Las ecuaciones de frecuencia cardiaca máxima (FCmax) se han utilizado por su fácil obtención y practicidad, en comparación con las pruebas de esfuerzo. Sin embargo, la ecuación más conocida "220 − edad" presenta baja fiabilidad y desviaciones de hasta 12 lat/min. Se han planteado nuevas fórmulas, pero estas no han sido correctamente validadas. El propósito de este estudio fue validar 7 ecuaciones de predicción utilizando una base de datos independiente. Se utiliza una base con datos de 634 sujetos (474 hombres y 160 mujeres) de 18-85 años, que fueron obtenidos como parte de un servicio de salud desarrollado en la Universidad de Michigan entre 1990-1992. Los sujetos realizaron una prueba de vO2max en banda sin fin, siguiendo un protocolo libre. Se utilizó la técnica de regresión lineal, en la que las ecuaciones adecuadas fueron aquellas que cumplieron con las dos hipótesis: pendiente = 1 y constante = 0. De acuerdo con los resultados, ninguna de las ecuaciones analizadas para toda la muestra aceptó ambas hipótesis. Al realizar el análisis de acuerdo con el sexo, seis de las ecuaciones cumplieron con las dos hipótesis para las mujeres, pero ninguna para los hombres; y, cuando se realizó de acuerdo con el grupo de edad, 4 de las ecuaciones cumplieron las hipótesis para el grupo de personas de 40 años o menos, pero no para el grupo de mayores de 40 años. La FCmax parece ser difícil de predecir por una única ecuación, por lo que se recomienda que, cuando se necesite una medida válida de esta variable, se recurra a una prueba directa.

Abstract Maximum heart rate equations (HRmax) have been used due to their easy availability and practicality, as compared to stress tests. However, the best-known equation, "220 - age", shows low reliability and deviations of up to 12 beats/min. New formulae have been proposed, but they have not been correctly validated. The purpose of this study was to validate 7 prediction equations by using and independent data base. A data base of 634 subjects (474 men and 160 women) from 18-85 years of age, obtained within a health service developed at the University of Michigan from 1990-1992, has been used. The subjects performed a vO2max test in a treadmill, following a free protocol. A linear regression technique was used in which the appropriate equations were those that met the two hypotheses: slope = 1 and constant = 0. According to the results, none of the equations analyzed for the full sample accepted both hypotheses. When doing the analysis by sex, six of the equations met the two hypotheses for the women, but none of them for the men; and when the analysis was done by age group, 4 of the equations met the hypotheses for the group 40 years old or younger, but not for those above 40. The HRmax seems to be difficult to predict through a single equation. Therefore, it is recommended that, when a valid measure for this variable is needed, a stress test be used.

Resumo As equações de predição da frequência cardíaca máxima (FCmax) têm sido utilizadas devido à sua facilidade de obtenção e praticidade, quando comparadas aos testes de esforço. No entanto, a equação mais conhecida "220 − idade" apresenta baixa confiabilidade e desvios de até 12 batimentos/min. Foram propostas novas fórmulas, entretanto não foram devidamente validadas. O objetivo deste estudo foi validar 7 equações de predição usando um banco de dados independente. Utiliza-se um banco de dados de 634 indivíduos (474 homens e 160 mulheres) com idades entre 18 e 85 anos, obtidos como parte de um serviço de saúde desenvolvido na Universidade de Michigan entre 1990-1992. Os sujeitos realizaram um teste de vO2máx em uma esteira, seguindo um protocolo livre. Utilizou-se a técnica de regressão linear, na qual as equações apropriadas foram aquelas que preencheram as duas hipóteses: inclinação = 1 e constante = 0. De acordo com os resultados, nenhuma das equações analisadas para toda a amostra aceitou ambas as hipóteses. Ao realizar a análise por sexo, seis das equações atenderam às duas hipóteses para as mulheres, mas nenhuma para os homens; e, quando realizadas de acordo com a faixa etária, 4 das equações atenderam às hipóteses para o grupo de pessoas com 40 anos ou menos, mas não para o grupo de pessoas com mais de 40 anos. A FCmax parece ser difícil de prever por uma única equação, por isso recomenda-se que, quando uma medida válida dessa variável for necessária, seja utilizado um teste direto.

Predictive utility of stress tests in the detection of asymptomatic coronary artery disease in atherosclerotic stroke patients.

INTRODUCTION: Whether and how atherosclerotic ischemic stroke patients should be investigated for asymptomatic coronary artery disease (CAD) is controversial. Our aim was to carry out a prospective observational study to determine the frequency and predictors of functionally significant coronary stenosis in these patients as well as the predictors of major adverse cardiovascular events (MACE) during post-stroke follow-up. MATERIAL AND METHODS: From January 2014 to June 2018, patients with atherosclerotic ischemic stroke were referred from the stroke unit to our cardiovascular department 3+/- 1 months after the acute event where they benefited from evaluation of cardiovascular risk factors, vascular and myocardial disease. Main outcome was defined as the prevalence of myocardial ischemia defined by perfusion stress echography 3 months after stroke. Secondary outcome (MACE) was defined as the incidence of stroke, transient ischemic attack (TIA), acute coronary syndrome, cardiovascular (CV) death or coronary or peripheral revascularization during a 3 year follow-up. RESULTS: Three hundred and twenty five patients (92% of strokes and 8% TIA) were included and median follow-up was 1075 days. At 3 months post-stroke, myocardial ischemia was found in 17 patients (5.2%). During the 3 year follow-up, 11 MACE occurred (3.4%, all in the non-ischemic group) of which 6 were recurrent strokes. In multivariate analysis, myocardial ischemia was significantly associated with the number of atheromatous vascular beds (OR 4.3; 95% CI, 1.7 to 10.6) and ECG signs of necrosis (OR 6.5; 95% CI, 1.9 to 21.9). MACE were also associated with ECG signs of necrosis (OR 3.5; 95% CI, 1.3 to 9.1), and unrelated to myocardial ischemia. CONCLUSION: Myocardial ischemia and CV events were infrequent and both strongly associated with ECG signs of necrosis, suggesting a low yield of stress tests and the potential for a more straightforward algorithm in the choice of patients eligible to coronary angiogram or other coronary imaging in post-stroke setting.

Changes in sympathetic nervous system activity after renal denervation: results from the randomised Oslo RDN study.

PURPOSE: Sympathetic nervous system (SNS) over-activity is associated with essential hypertension. Renal sympathetic denervation (RDN) possibly lowers office- and ambulatory blood pressure (BP) in patients with treatment-resistant hypertension (TRH). We aimed to assess the effect of RDN compared to drug adjustment on SNS activity among patients with TRH by measuring plasma catecholamines and heart rate variability (HRV) during stress tests. MATERIALS AND METHODS: Patients with TRH were randomised to RDN (n = 9) or Drug Adjustment (DA) (n = 10). We measured continuous HRV and beat-to-beat-BP using FinaPres® and obtained plasma catecholamines during standardised orthostatic- and cold-pressor stress tests (CPT) before- and six months after randomisation. RESULTS: CPT revealed no differences between groups at baseline in peak adrenaline concentration (69.3 pg/mL in the DA group vs. 70.0 pg/mL in the RDN group, p = 0.38) or adrenaline reactivity (Δ23.1 pg/mL in the DA group vs. Δ29.3 pg/mL in the RDN group, p = 0.40). After six months, adrenaline concentrations were statistically different between groups after one minute (66.9 pg/mL in the DA group vs. 55.3 pg/mL in the RDN group, p = 0.03), and six minutes (62.4 pg/mL in the DA group vs. 50.1 pg/mL in the RDN group, p = 0.03). There was a tendency of reduction in adrenaline reactivity after six months in the RDN group (Δ26.3 pg/mL at baseline vs. Δ12.8 pg/ml after six months, p = 0.08), while it increased in the DA group (Δ13.6 pg/mL at baseline vs. Δ19.9 pg/mL after six months, p = 0.53). We also found a difference in the Low Frequency band at baseline following the CPT (667µs2 in the DA group vs. 1628µs2 in the RDN group, p = 0.03) with a clear tendency of reduction in the RDN group to 743µs2 after six months (p = 0.07), compared to no change in the DA group (1052µs2,p = 0.39). CONCLUSION: Our data suggest that RDN reduces SNS activity after six months. This finding warrants investigation in a larger study. Clinical Trial Number registered at www.clinicaltrials.gov: NCT01673516.

Gender-Related Differences in Clinical Presentation and Angiographic Findings in Patients with Ischemia and No Obstructive Coronary Artery Disease (INOCA): A Single-Center Observational Registry.

Ischemia and no obstructive coronary arteries (INOCA) is a common clinical presentation, with a variety of causes that are often not fully investigated in routine clinical practice. The goal of our study was to characterize a real-world population of patients with INOCA, with a deeper focus on symptoms and stress test findings. The study population consisted of 435 patients who underwent diagnostic coronary angiography for anginal symptoms and/or evidence of myocardial ischemia at non-invasive imaging. In all patients angiography demonstrated nonobstructive coronary artery disease (CAD, less than 30% luminal diameter stenosis or fractional flow reserve > 0.8 and/or instantaneous wave-free ratio > 0.89). Fifty-four percent of the patients were women. Atypical clinical presentation was more common in women (59.5 vs. 49.5%, p = 0.037). Women were more likely to have normal coronary arteries than men (41.8 vs. 16.2%, p < 0.001), and less likely than men to have hemodynamically non-significant CAD (32.1 vs. 55.1%, p < 0.001). No significant correlation between typicality of symptoms and evidence of ischemia was found in those patients (244/435, 56.1%) who had either dobutamine stress echocardiography or electrocardiogram stress test. INOCA is a common clinical condition, prevalent in women often presenting with atypical symptoms.

Depression anticipates patients at risk of poor exercise stress test performance after percutaneous coronary angioplasty: A short-term longitudinal study.

AIMS: The exercise stress test is commonly used to assess physical capacity and recovery in coronary artery disease (CAD) patients after percutaneous transluminal coronary angioplasty (PTCA). Despite depressive symptoms have been consistently associated with adverse outcomes in CAD patients, they are rarely considered as risk factors of poor exercise test. The present study investigated the influence of depressive symptoms, along with anxiety, sleep problems and perceived health on exercise test in PTCA patients. METHODS: One hundred and sixty-five patients who underwent PTCA completed the Beck Depression Inventory-II (BDI-II), the Beck Anxiety Inventory, the Sleep Condition Index and the 12-item Short-Form Health Survey and, after 20 days, underwent exercise stress test. RESULTS: Higher BDI-II scores significantly predicted lower maximal workload measured in metabolic equivalents (METs; ß = -0.13; p = .030), shorter total exercise duration (ß = -5.23; p = .034) and the inability to reach maximum heart rate during exercise test (OR = 1.07; p = .032), even after controlling for relevant sociodemographic and biomedical risk factors. CONCLUSIONS: Depressive symptoms specifically predicted worse exercise stress test performance in patients after PTCA, controlling for common risk factors. Focusing on the assessment of depressive symptoms, in addition to sociodemographic and biomedical risk factors, is essential to anticipate patients at risk of poor physical capacity after PTCA.

Sodium, potassium, calcium lactobionates, and lactobionic acid from Zymomonas mobilis: A novel approach about stability and stress tests.

The bioproduction of lactobionic acid and its salts can be performed by enzymatic complex glucose-fructose oxidoreductase (GFOR) and glucono-δ-lactonase (GL) of Zymomonas mobilis. Considering the applicability of these compounds in pharmaceutical area, the aim of this study was to assess the accelerated and long-term stability studies of sodium, potassium, calcium lactobionate, and lactobionic acid. Furthermore, stress tests were performed to evaluate the stability against pH, temperature and oxidation. The samples submitted to degradation tests were analyzed by high-performance liquid chromatography (HPLC) and high-resolution mass spectrometry analysis (HRMS-ESI-QTOF). Sodium, potassium, and calcium lactobionate were stable for six months of analyses considering the accelerated (40 °C and 75% RH) and long-term (30 °C and 75% RH) stability studies. The presence of lactobiono-δ-lactone and a significant increase in moisture were observed for both biosynthesized and commercially available lactobionic acid samples. Against the forced degradation tests, all the lactobionate salts and lactobionic acid showed to be stable upon alkaline and acid pH conditions, at 60 and 80 °C, and also against UV light exposition. Furthermore, the presence of lactobiono-δ-lactone form was observed in lactobionic acid samples. However, the degradation of both lactobionic acid and lactobionate salts was evident in the presence of hydrogen peroxide. This degradation kinetic profile suggests, that lactobionate salts follows a zero-order reaction model and lactobionic acid follows a second-order kinetic. The MS analysis of the main degradation product suggests a molecular formula C11H20O10 resulting from the oxidative decarboxylation. This report brings an amount of results as contribution to the scarce information regarding the chemical and physical-chemical stability of sodium, potassium, calcium lactobionate, and lactobionic acid. These data may be useful and serve as reference, in view of the multipurpose applications of the cited compounds.

The Utilization of Stress Tests Prior to Percutaneous Coronary Intervention for Stable Coronary Artery Disease in Taiwan.

BACKGROUND: Ischemia shown in non-invasive tests is considered to be a fundamental requirement for treating patients with stable coronary artery disease (CAD) with a percutaneous coronary intervention (PCI). In a nationwide cohort, we investigated the utilization of stress tests, including myocardial perfusion imaging (MPI), treadmill exercise test (TET) and stress echocardiography (SE) prior to elective PCI. METHODS: This retrospective study used the Longitudinal Health Insurance Database 2000 (LHID2000) of the National Health Insurance program in Taiwan. The LHID2000 is comprised of one million randomly sampled beneficiaries. We enrolled patients receiving elective PCI for stable CAD from 2000 to 2013. Stress tests performed within 90 days prior to PCI and patient characteristics correlated with the utilization of stress tests were investigated. RESULTS: During the investigation period, 3,163 patients received elective PCI for stable CAD and 1,847 (58.4%) patients had at least one stress test within 90 days prior to PCI. Among them, 1,461 (79.1%) had MPI, 1,228 had TET (66.4%) and only 1 had SE (0.05%). Age < 80 years, regional hospital and hyperlipidemia were independently associated with an increased likelihood of receiving stress tests. On the other hand, Charlson-comorbidity index score ≥ 1, prior catheterization and heart failure were independently associated with a decreased likelihood of receiving stress tests. CONCLUSIONS: In the setting of stable CAD, almost 60% of our patients received stress tests within 90 days prior to elective PCI, and MPI was the most commonly used test.

The occult hemodynamically significant left main stenosis in the asymptomatic patient: Reconciling the visual-functional mismatch - A case report and review of screening appropriateness and assessment of left main in patient with multi-vessel CAD.

We present a 40 year old asymptomatic man with mild left main artery narrowing who demonstrated extreme discordance between symptom presentation and ischemic burden i.e. visual (angiographic) and ischemic (functional) mismatch. The use of an appropriately selected screening stress test can lead to an appropriate decision for revascularization, supported by landmark risk assessment documents and revascularization trials.

Application of exercise ECG stress test in the current high cost modern-era healthcare system.

Exercise electrocardiogram (ECG) tests boasts of being more widely available, less resource intensive, lower cost and absence of radiation. In the presence of a normal baseline ECG, an exercise ECG test is able to generate a reliable and reproducible result almost comparable to Technitium-99m sestamibi perfusion imaging. Exercise ECG changes when combined with other clinical parameters obtained during the test has the potential to allow effective redistribution of scarce resources by excluding low risk patients with significant accuracy. As we look towards a future of rising healthcare costs, increased prevalence of cardiovascular disease and the need for proper allocation of limited resources; exercise ECG test offers low cost, vital and reliable disease interpretation. This article highlights the physiology of the exercise ECG test, patient selection, effective interpretation, describe previously reported scores and their clinical application in today's clinical practice.

Association of Liability Concerns with Decisions to Order Echocardiography and Cardiac Stress Tests with Imaging.

BACKGROUND: Professional societies have made efforts to curb overuse of cardiac imaging and decrease practice variation by publishing appropriate use criteria. However, little is known about the impact of physician-level determinants such as liability concerns and risk aversion on decisions to order testing. METHODS: A web-based survey was administered to cardiologists and general practice physicians affiliated with two academic institutions. The survey consisted of four clinical scenarios in which appropriate use criteria rated echocardiography or stress testing as "may be appropriate." Respondents' degree of liability concerns and risk aversion were measured using validated tools. The primary outcome variable was tendency to order imaging, calculated as the average likelihood to order an imaging test across the clinical scenarios (1 = very unlikely, 6 = very likely). Linear regression models were used to evaluate the association between tendency to order imaging and physician characteristics. RESULTS: From 420 physicians invited to participate, 108 complete responses were obtained (26% response rate, 54% cardiologists). There was no difference in tendency to order imaging between cardiologists and general practice physicians (3.46 [95% CI, 3.12-3.81] vs 3.15 [95% CI, 2.79-3.51], P = .22). On multivariate analysis, a higher degree of liability concerns was the only significant predictor of decisions to order imaging (mean difference in tendency to order imaging, 0.36; 95% CI, 0.09-0.62; P = .01). CONCLUSION: In clinical situations in which performance of cardiac imaging is rated as "may be appropriate" by appropriate use criteria, physicians with higher liability concerns ordered significantly more testing than physicians with lower concerns.

Effects of different surface modification and contents on municipal solid waste incineration fly ash/epoxy composites.

Incineration fly ash, a waste from municipal solid waste incineration plant can be used to replace conventional filler as reinforcing filler to enhance the mechanical strength of a composite. Surface modification was performed on the incineration fly ash before mixing into the soft polymer matrix so as to improve interfacial bond of the filler and epoxy resin. In this study, detailed characterisation of mechanical, morphological and leaching behaviours of municipal solid waste incineration (MSWI) fly ash infused composite has been carried out. Flexural and tensile test was conducted to determine the effect on mechanical properties of the composite by varying the concentration of incineration fly ash filler added into polymer matrix and surface modification of incineration fly ash filler using silane coupling agent and colloidal mesoporous silica (CMS). The results indicated that composite infused with incineration fly ash filler surface treated with CMS shown improvement on the tensile and flexural strengths. In addition, SEM images showed that surface modification of incineration fly ash with colloidal mesoporous silica enhanced the interfacial bonding with polymer resin which explained the improvement of mechanical strength. Leaching test showed result of toxic metals such as Pb, Zn, Fe, Cu, Cr, Cd and Rb immobilised in the polymer matrix of the composite. Hence, the use of MSWI fly ash as reinforcing filler in the composite appears green and sustainable because this approach is a promising opportunity to substitute valuable raw material with MSWI fly ash.

[Blepharoptosis: diagnostic tests]. / Blefaroptoz: diagnosticheskie testy.

The article discusses diagnostic algorithms for blepharoptosis in patients with Horner's syndrome, myasthenia, chronic progressive ophthalmoplegia, myotonic dystrophy, and acute neurovascular events. Basic methods for evaluating the upper eyelid position and ptosis severity as well as special pharmacologic stress tests to reveal the true etiology of the condition and make the best treatment choice are described.

Can biofeedback training of psychophysiological responses enhance athletes' sport performance? A practitioner's perspective.

BACKGROUND: In recent years, biofeedback has become increasingly popular for its proven success in peak performance training - the psychophysiological preparation of athletes for high-stakes sport competitions, such as the Olympic games. The aim of this research was to test whether an 8-week period of exposure to biofeedback training could improve the psychophysiological control over competitive anxiety and enhance athletic performance in participating subjects. METHODS: Participants of this study were highly competent athletes, each training in different sport disciplines. The experimental group consisted of 18 athletes (4 women, 14 men), whereas the Control group had 21 athletes (4 women, 17 men). All athletes were between 16 and 34 years old. The biofeedback device, Nexus 10, was used to detect and measure the psychophysiological responses of athletes. Athletes from both groups (control and experimental) were subjected to stress tests at the beginning of the study and once again at its conclusion. In between, the experimental group received training in biofeedback techniques. We then calculated the overall percentage of athletes in the experimental group compared with those in the control group who were able to control respiration, skin conductance, heart rate, blood flow amplitude, heart rate variability, and heart respiration coherence. One year following completion of the initial study, we questioned athletes from the experimental group, to determine whether they continued to use these skills and if they could detect any subsequent enhancement in their athletic performance. RESULTS: We demonstrated that a greater number of participants in the experimental group were able to successfully control their psychophysiological parameters, in comparison to their peers in the control group. Significant results (p < 0.05) were noted in regulation of GSR following short stress test conditions (p = 0.037), in regulation of HR after exposure to STROOP stressor (p = 0.037), in regulation of GSR following the Math and GSR stressors (p = 0.033, p = 0.409) and in achieving HR - breathing coherence following the math stressor (p = 0.042). CONCLUSION: One year following completion of the training program, all participants from the experimental group indicated that they were still using the biofeedback - psycho-regulation skills. Furthermore, these participants uniformly reported believing that these skills had enhanced their athletic performance and general well-being.

PET/MR imaging: current and future applications for cardiovascular disease.

PET and magnetic resonance (MR) imaging have each become essential tools in the workup and management of cardiac patients. Combined PET/MR systems have recently been developed, allowing for single-session imaging using both modalities. This new technology holds great promise for cardiac applications given the different, yet complementary, information each modality provides. Research in this area is still nascent, although early studies have been promising.

Adenosine stress cardiovascular magnetic resonance with variable-density spiral pulse sequences accurately detects coronary artery disease: initial clinical evaluation.

BACKGROUND: Adenosine stress cardiovascular magnetic resonance perfusion imaging can be limited by motion-induced dark-rim artifacts, which may be mistaken for true perfusion abnormalities. A high-resolution variable-density spiral pulse sequence with a novel density compensation strategy has been shown to reduce dark-rim artifacts in first-pass perfusion imaging. We aimed to assess the clinical performance of adenosine stress cardiovascular magnetic resonance using this new perfusion sequence to detect obstructive coronary artery disease. METHODS AND RESULTS: Cardiovascular magnetic resonance perfusion imaging was performed during adenosine stress (140 µg/kg per minute) and at rest on a Siemens 1.5-T Avanto scanner in 41 subjects with chest pain scheduled for coronary angiography. Perfusion images were acquired during injection of 0.1 mmol/kg Gadolinium-diethylenetriaminepentacetate at 3 short-axis locations using a saturation recovery interleaved variable-density spiral pulse sequence. Significant stenosis was defined as >50% by quantitative coronary angiography. Two blinded reviewers evaluated the perfusion images for the presence of adenosine-induced perfusion abnormalities and assessed image quality using a 5-point scale (1 [poor] to 5 [excellent]). The prevalence of obstructive coronary artery disease by quantitative coronary angiography was 68%. The average sensitivity, specificity, and accuracy were 89%, 85%, and 88%, respectively, with a positive predictive value and negative predictive value of 93% and 79%, respectively. The average image quality score was 4.4±0.7, with only 1 study with more than mild dark-rim artifacts. There was good inter-reader reliability with a κ statistic of 0.67. CONCLUSIONS: Spiral adenosine stress cardiovascular magnetic resonance results in high diagnostic accuracy for the detection of obstructive coronary artery disease with excellent image quality and minimal dark-rim artifacts.

Assessment of the new appropriate use criteria for diagnostic catheterization in the detection of coronary artery disease following noninvasive stress testing.

BACKGROUND: Appropriate use criteria (AUC) for diagnostic catheterization (DC) developed by the American College of Cardiology Foundation (ACCF) and other professional societies were recently published. These criteria have yet to be examined thoroughly using existing DC databases. METHODS AND RESULTS: New York State's Cardiac Diagnostic Catheterization Database was used to identify patients undergoing DC "for suspected coronary artery disease (CAD)" in 01/2010-06/2011 who underwent noninvasive stress testing. Patients rated for appropriateness using symptoms and stress test results were examined to determine the percentage with obstructive CAD and to explore the benefit of adding Global Risk Score (GRS) to the AUC. Of the 4432 patients who could be rated, 1530 (34.5%) had obstructive CAD, which varied from 22% for patients rated inappropriate to 47% for patients rated appropriate. Of all patients with low risk stress test results/no symptoms, all of whom were rated "inappropriate" for DC, only 8% of those patients with low GRS had obstructive CAD, whereas 44% of the patients with high GRS had obstructive CAD. CONCLUSIONS: Global Risk Score improved the ability of symptoms and stress test results to identify obstructive CAD in patients with "suspected CAD" with prior stress tests, and it might be helpful to add GRS to the DC AUC for those patients. These findings should be regarded as hypothesis generating unless/until they can be confirmed by other data bases.