The AFLETES Study: Atrial Fibrillation in Veteran Athletes and the Risk of Stroke.

OBJECTIVES: Endurance athletes are at an increased risk of atrial fibrillation (AF) when compared with the general population. However, the risk of stroke in athletes with AF is unknown. DESIGN AND SETTING: We aimed to assess this risk using an international online survey. PATIENTS: Individuals that had competed in ≥1 competitive events and were ≥40 years old were included. INTERVENTIONS: Self-reported demographic, medical history, and training history data were collected, and a CHA 2 DS 2 -VASc was calculated. MAIN OUTCOME MEASURES: Binary logistic regression was used to assess variables associated with AF and stroke. RESULTS: There were 1002 responses from participants in 41 countries across Africa, Asia, Australasia, Europe, and North and South America, and 942 were included in the final analysis. The average age was 52.4 ± 8.5 years, and 84% were male. The most common sports were cycling (n = 677, 72%), running (n = 558, 59%), and triathlon (n = 245, 26%). There were 190 (20%) individuals who reported AF and 26 individuals (3%) who reported stroke; of which, 14 (54%) had AF. Lifetime exercise dose [odds ratio (OR), 1.02, 95% confidence interval (95% CI),1.00-1.03, P = 0.02] and swimming (OR, 1.56, 95% CI, 1.02-2.39, P = 0.04) were associated with AF in multivariable analysis, independent of other risk factors. Atrial fibrillation was associated with stroke (OR, 4.18, 95% CI, 1.80-9.72, P < 0.01), even in individuals with a low (0/1) CHA 2 DS 2 -VASc score (OR, 4.20, 95% CI, 1.83-9.66, P < 0.01). CONCLUSIONS: This survey provides early evidence that veteran endurance athletes who develop AF may be at an increased risk of developing stroke, even in those deemed to be at low risk by CHA 2 DS 2 -VASc score.

The role of 4-dimensional flow in the assessment of bicuspid aortic valve and its valvulo-aortopathies.

Bicuspid aortic valve is the most common congenital cardiac malformation and the leading cause of aortopathy and aortic stenosis in younger patients. Aortic wall remodelling secondary to altered haemodynamic flow patterns, changes in peak velocity, and wall shear stress may be implicated in the development of aortopathy in the presence of bicuspid aortic valve and dysfunction. Assessment of these parameters as potential predictors of disease severity and progression is thus desirable. The anatomic and functional information acquired from 4D flow MRI can allow simultaneous visualisation and quantification of the pathological geometric and haemodynamic changes of the aorta. We review the current clinical utility of haemodynamic quantities including velocity, wall sheer stress and energy losses, as well as visual descriptors such as vorticity and helicity, and flow direction in assessing the aortic valve and associated aortopathies.

Low-Dose Radiation Advances in Coronary Computed Tomography Angiography in the Diagnosis of Coronary Artery Disease.

BACKGROUND: Coronary computed tomography angiography (CCTA) is now widely used in the diagnosis of coronary artery disease since it is a rapid, minimally invasive test with a diagnostic accuracy comparable to coronary angiography. However, to meet demands for increasing spatial and temporal resolution, higher x-ray radiation doses are required to circumvent the resulting increase in image noise. Exposure to high doses of ionizing radiation with CT imaging is a major health concern due to the potential risk of radiation-associated malignancy. Given its increasing use, a number of dose saving algorithms have been implemented to CCTA to minimize radiation exposure to "as low as reasonably achievable (ALARA)" without compromising diagnostic image quality. OBJECTIVE: The purpose of this review is to outline the most recent advances and current status of dose saving techniques in CCTA. METHOD: PubMed, Medline, EMBASE and Scholar databases were searched to identify feasibility studies, clinical trials, and technology guidelines on the technical advances in CT scanner hardware and reconstruction software. RESULTS: Sub-millisievert (mSv) radiation doses have been reported for CCTA due to a combination of strategies such as prospective electrocardiogram-gating, high-pitch helical acquisition, tube current modulation, tube voltage reduction, heart rate reduction, and the most recent novel adaptive iterative reconstruction algorithms. CONCLUSION: Advances in radiation dose reduction without loss of image quality justify the use of CCTA as a non-invasive alternative to coronary catheterization in the diagnosis of coronary artery disease.

Low-radiation and high image quality coronary computed tomography angiography in "real-world" unselected patients.

AIM: To determine the radiation dose and image quality in coronary computed tomography angiography (CCTA) using state-of-the-art dose reduction methods in unselected "real world" patients. METHODS: In this single-centre study, consecutive patients in sinus rhythm underwent CCTA for suspected coronary artery disease (CAD) using a 320-row detector CT scanner. All patients underwent the standard CT acquisition protocol at our institute (Morriston Hospital) a combination of dose saving advances including prospective electrocardiogram-gating, automated tube current modulation, tube voltage reduction, heart rate reduction, and the most recent novel adaptive iterative dose reconstruction 3D (AIDR3D) algorithm. The cohort comprised real-world patients for routine CCTA who were not selected on age, body mass index, or heart rate. Subjective image quality was graded on a 4-point scale (4 = excellent, 1 = non-diagnostic). RESULTS: A total of 543 patients were included in the study with a mean body weight of 81 ± 18 kg and a pre-scan mean heart rate of 70 ± 11 beats per minute (bpm). When indicated, patients received rate-limiting medication with an oral beta-blocker followed by additional intravenous beta-blocker to achieve a heart rate below 65 bpm. The median effective radiation dose was 0.88 mSv (IQR, 0.6-1.4 mSv) derived from a Dose Length Product of 61.45 mGy.cm (IQR, 42.86-100.00 mGy.cm). This also includes what we believe to be the lowest ever-reported radiation dose for a routine clinical CCTA (0.18 mSv). The mean image quality (± SD) was 3.65 ± 0.61, with a subjective image quality score of 3 ("good") or above for 93% of patient CCTAs. CONCLUSION: Combining a low-dose scan protocol and AIDR3D with a 320-detector row CT scanner can provide high quality images at exceptionally low radiation dose in unselected patients being investigated for CAD.

Solvatochromic effects on the photoinduced charge-transfer states in donor-acceptor substituted polydioctylfluorenes.

Polymer morphology affects quantum efficiency. The influence of polymer morphology on the emission from charge transfer states within donor-acceptor (D-A) polydioctylfluorene derivatives is investigated. Two D-A copolymers, comprising one- and two-electron-donating triphenylamines substituted into the electron-accepting dioctylfluorene repeat unit were studied. Time-resolved emission spectra (with a resolution of 330 fs) in both liquid and glass phase isolate nuclear relaxation to the large-amplitude motion of the triphenylamine moiety about the single bond, analogous to the twisted intramolecular charge-transfer (TICT) model. The charge separation in the polymers' emitting states is therefore increased, suggesting a potential approach to enhance quantum efficiency in devices otherwise limited by exciton recombination.

Optical analogue of the spin Hall effect in a photonic cavity.

We observe anisotropy in the polarization flux generated in a GaAs/AlAs photonic cavity by optical illumination, equivalent to spin currents in strongly coupled microcavities. Polarization rotation of the scattered photons around the Rayleigh ring is due to the TE-TM splitting of the cavity mode. Resolving the circular polarization components of the transmission reveals a separation of the polarization flux in momentum space. These observations constitute the optical analogue of the spin Hall effect.