Impaired coronary blood flow at higher heart rates during atrial fibrillation: investigation via multiscale modelling

Background. Different mechanisms have been proposed to relate atrial fibrillation (AF) and coronary flow impairment, even in absence of relevant coronary artery disease (CAD). However, the underlying hemodynamics remains unclear. Aim of the present work is to computationally explore whether and to what extent ventricular rate during AF affects the coronary perfusion. Methods. AF is simulated at different ventricular rates (50, 70, 90, 110, 130 bpm) through a 0D-1D multiscale validated model, which combines the left heart-arterial tree together with the coronary circulation. Artificially-built RR stochastic extraction mimics the \emph{in vivo} beating features. All the hemodynamic parameters computed are based on the left anterior descending (LAD) artery and account for the waveform, amplitude and perfusion of the coronary blood flow. Results. Alterations of the coronary hemodynamics are found to be associated either to the heart rate increase, which strongly modifies waveform and amplitude of the LAD flow rate, and to the beat-to-beat variability. The latter is overall amplified in the coronary circulation as HR grows, even though the input RR variability is kept constant at all HRs. Conclusions. Higher ventricular rate during AF exerts an overall coronary blood flow impairment and imbalance of the myocardial oxygen supply-demand ratio. The combined increase of heart rate and higher AF-induced hemodynamic variability lead to a coronary perfusion impairment exceeding 90-110 bpm in AF. Moreover, it is found that coronary perfusion pressure (CPP) is no longer a good measure of the myocardial perfusion for HR higher than 90 bpm.Comment: 8 pages, 5 figures, 3 table

Aspirin and the Primary Prevention of Cardiovascular Diseases. An Approach Based on Individualized, Integrated Estimation of Risk

While the use of aspirin in the secondary prevention of cardiovascular (CVD) is well established, aspirin in primary prevention is not systematically recommended because the absolute CV event reduction is similar to the absolute excess in major bleedings. Recently, emerging evidence suggests the possibility that the assumption of aspirin, may also be effective in the prevention of cancer. By adding to the CV prevention benefits the potential beneficial effect of aspirin in reducing the incidence of mortality and cancer could tip the balance between risks and benefits of aspirin therapy in the primary prevention in favour of the latter and broaden the indication for treatment with in populations at average risk. While prospective and randomized study are currently investigating the effect of aspirin in prevention of both cancer and CVD, clinical efforts at the individual level to promote the use of aspirin in global (or total) primary prevention could be already based on a balanced evaluation of the benefit/risk ratio

Cardiovascular deconditioning during long-term spaceflight through multiscale modeling

Human spaceflight has been fascinating man for centuries, representing the intangible need to explore the unknown, challenge new frontiers, advance technology and push scientific boundaries further. A key area of importance is cardiovascular deconditioning, that is, the collection of hemodynamic changes - from blood volume shift and reduction to altered cardiac function - induced by sustained presence in microgravity. A thorough grasp of the 0G adjustment point per se is important from a physiological viewpoint and fundamental for astronauts' safety and physical capability on long spaceflights. However, hemodynamic details of cardiovascular deconditioning are incomplete, inconsistent and poorly measured to date; thus a computational approach can be quite valuable. We present a validated 1D-0D multiscale model to study the cardiovascular response to long-term 0G spaceflight in comparison to the 1G supine reference condition. Cardiac work, oxygen consumption and contractility indexes, as well as central mean and pulse pressures were reduced, augmenting the cardiac deconditioning scenario. Exercise tolerance of a spaceflight traveler was found to be comparable to an untrained person with a sedentary lifestyle. At the capillary-venous level significant waveform alterations were observed which can modify the regular perfusion and average nutrient supply at the cellular level. The present study suggests special attention should be paid to future long spaceflights which demand prompt physical capacity at the time of restoration of partial gravity (e.g., Moon/Mars landing). Since spaceflight deconditioning has features similar to accelerated aging understanding deconditioning mechanisms in microgravity are also relevant to the understanding of aging physiology on Earth.Comment: 14 pages, 5 tables, 5 figure

A multiscale modelling of the cardiovascular fluid dynamics for clinical and space applications

L'abstract è presente nell'allegato / the abstract is in the attachmen

How to classify the stylohyoid complex syndrome in the ICHD

We have read the International Classification of Headache Disorders, third edition (beta) (ICHD-3 beta), and for the first time headaches are attributed to inflammation of the stylohyoid ligament (SL). It is included among the secondary headaches in “Headache or facial pain attributed to disorder of the cranium, neck, eyes, ears, nose, sinuses, teeth, mouth or other facial or cervical structure.

The QUAX proposal: a search of galactic axion with magnetic materials

Aim of the QUAX (QUaerere AXion) proposal is to exploit the interaction of cosmological axions with the spin of electrons in a magnetized sample. Their effect is equivalent to the application of an oscillating rf field with frequency and amplitude which are fixed by axion mass and coupling constant, respectively. The rf receiver module of the QUAX detector consists of magnetized samples with the Larmor resonance frequency tuned to the axion mass by a polarizing static magnetic field. The interaction of electrons with the axion-equivalent rf field produces oscillations in the total magnetization of the samples. To amplify such a tiny field, a pump field at the same frequency is applied in a direction orthogonal to the polarizing field. The induced oscillatory magnetization along the polarizing field is measured by a SQUID amplifier operated at its quantum noise level.Comment: 5 pages, Contribution for the proceedings of the TAUP2015, International Conference on Topics in Astroparticle and Underground Physics, 7-11 September 2015, Torino, Ital

Clinic manifestations in granulomatosis with polyangiitis

Granulomatosis with polyangiitis (GPA), formerly Wegener's granulomatosis (WG), is an uncommon immunologically mediated systemic small-vessel vasculitis that is pathologically characterised by an inflammatory reaction pattern (necrosis, granulomatous inflammation and vasculitis) that occurs in the upper and lower respiratory tracts and kidneys. Although the aetiology of GPA remains largely unknown, it is believed to be autoimmune in origin and triggered by environmental events on a background of genetic susceptibility.In Europe, the prevalence of GPA is five cases per 100,000 population, with greater incidence in Northern Europe. GPA can occur in all racial groups but predominantly affects Caucasians. Both sexes are affected equally. GPA affects a wide age range (age range, 8-99 years).Granulomatosis with polyangiitis is characterised by necrotising granulomatous lesions of the respiratory tract, vasculitis and glomerulonephritis. Classically, the acronym ELK is used to describe the clinical involvement of the ear, nose and throat (ENT); lungs; and kidneys. Because the upper respiratory tract is involved in 70-100% of cases of GPA, classic otorhinolaryngologic symptoms may be the first clinical manifestation of disease. The nasal cavity and the paranasal sinuses are the most common sites of involvement in the head and neck area (85-100%), whereas otological disease is found in approximately 35% (range, 19-61%) of cases.Diagnosis of GPA is achieved through clinical assessment, serological tests for anti-neutrophil cytoplasmic antibodies (ANCA) and histological analysis. The 10-year survival rate is estimated to be 40% when the kidneys are involved and 60-70% when there is no kidney involvement.The standard therapy for GPA is a combination of glucocorticoids and cyclophosphamide. In young patients, cyclophosphamide should be switched to azathioprine in the maintenance phase.A multidisciplinary approach, involving otorhinolaryngologists, oral and maxillofacial surgeons, oral physicians, rheumatologists, renal and respiratory physicians, and ophthalmologists, is necessary for the diagnosis and therapeutic treatment of GPA. ENT physicians have a determining role in recognising the early onset of the disease and starting an appropriate therapy