Low flow low gradient aortic stenosis: clinical pathways

AbstractAortic stenosis patients with severe LV dysfunction and low cardiac output present with relatively low transvalvular gradients. It is difficult to distinguish them from aortic sclerosis and LV dysfunction with low cardiac output. The former condition is severe AS with LV dysfunction and latter is primarily a contractile dysfunction. Dobutamine stress echocardiogram is key to diagnosis.AS with LV dysfunction associated with preserved contractile reserve benefit from valve replacement and those without contractile reserve needs critical evaluation on a case to case basis. Patients of AS with LV dysfunction with associated coronary artery disease need coronary angiograms to decide regarding need for valve replacement with bypass surgery. A subset of AS patients have low flow, low mean gradients with preserved ejection fraction in whom one must evaluate global hemodynamic load to assess ventriculo-arterial impedence.In this review an approach to the clinical pathways for assessment of low flow, low gradient aortic stenosis has been discussed

Risk factor profile of calcific aortic stenosis

AbstractBackgroundCalcific aortic stenosis and coronary artery disease share common risk factors. In some of the previous studies statins have been used to retard the progression of aortic stenosis, but the results were inconsistent.MethodsOne hundred and ten patients of CAS above the age of 40 years have undergone clinical, biochemical and echocardiographic evaluation. Coronary angiograms were done in 66% of them.ResultsMale to female ratio was 2:1. Patients of CAS with CAD showed higher prevalence of diabetes, hypertension, dyslipidemia, smoking and family history of CAD. Prevalence of obesity and bicuspid aortic valve by echocardiogram was high in those without CAD.ConclusionsOn comparison of prevalence of risk factor in those with and without associated CAD, there was higher prevalence of diabetes (65% vs 30%), hypertension (52% vs 43%), dyslipidemia (69% vs 52%), smoking (24% vs 18%) and family history of CAD (34% vs 16%) in those with associated CAD. The incidence of obesity was higher in those without CAD (20% vs 30%). The difference observed in diabetes alone was found to be statistically significant

An improved continuous compositional-spread technique based on pulsed-laser deposition and applicable to large substrate areas

A new method for continuous compositional-spread (CCS) thin-film fabrication based on pulsed-laser deposition (PLD) is introduced. This approach is based on a translation of the substrate heater and the synchronized firing of the excimer laser, with the deposition occurring through a slit-shaped aperture. Alloying is achieved during film growth (possible at elevated temperature) by the repeated sequential deposition of sub-monolayer amounts. Our approach overcomes serious shortcomings in previous in-situ implementations of CCS based on sputtering or PLD, in particular the variations of thickness across the compositional spread and the differing deposition energetics as function of position. While moving-shutter techniques are appropriate for PLD-approaches yielding complete spreads on small substrates (i.e. small as compared to distances over which the deposition parameters in PLD vary, typically about 1 cm), our method can be used to fabricate samples that are large enough for individual compositions to be analyzed by conventional techniques, including temperature-dependent measurements of resistivity and dielectric and magnetic and properties (i.e. SQUID magnetometry). Initial results are shown for spreads of (Sr,Ca)RuO$_3$.Comment: 6 pages, 8 figures, accepted for publication in Rev. Sci. Instru

The limits of India’s ethno-linguistic federation: understanding the demise of Sikh nationalism

From 1984 until 1993, the Indian state of Punjab witnessed a sustained insurgency by Sikh militants campaigning for a separate sovereign state. This insurgency was ultimately defeated by the overwhelming use of security force that officially resulted in the deaths of 30,000 people. By the mid-1990s, a ‘normalcy’ had returned to Punjab politics, but the underlying issues which had fuelled the demand for separatism remain unaddressed. This paper examines critically the argument that India’s ethno-linguistic federation is exceptional in accommodating ethno-nationalist movements. By drawing on the Punjab case study, it argues that special considerations apply to the governance of peripheral regions (security, religion). Regional elites in these states struggle to build legitimacy because such legitimacy poses a threat to India’s nation and state-building. In short, India’s ethno-linguistic federation is only partially successful in managing ethno-linguistic demands in the peripheral Indian states

Extended Use of Ivabradine in Heart Failure with Preserved Ejection Fraction and Inappropriate Sinus Tachycardia

Ivabradine has been used for over a decade in managing chronic coronary syndromes and heart failure (HF) with reducedejection fraction (HFrEF). HF with preserved ejection fraction (HFpEF) accounts for 50% of the total HF cases carrying equalmortality and morbidity risk as HFrEF. Increased heart rate (HR) in such cases has been shown to be associated with poorclinical outcomes. Clinical conditions like inappropriate sinus tachycardia (IST) manifest with elevated HR without anyspecific triggers. Beta-blockers have been the preferred treatment of choice for both HFpEF and IST but are often ineffective orpresent with side effects due to their negative ionotropic effects. Ivabradine, through its inhibitory action on funny current(Ifc), reduces HR without altering the inotropic mechanism. Few case reports and small case series have documented itsextended use and efficacy in reducing HR in these cardiac conditions. In this article, we present two cases who needed HRcontrol, one with HFpEF and another case of IST syndrome. Ivabradine was successfully used in both these cases to controlthe elevated HR

Effect of reagent rotation on the cross section for the reaction lithium + hydrogen fluoride .fwdarw. lithium fluoride + hydrogen

This article does not have an abstract

Calcific aortic valve disease: Is it another face of atherosclerosis?

Calcific aortic valve disease (CAVD) is the most common valvular heart disease in the elderly. As life expectancy increases, prevalence of CAVD is expected to rise. CAVD is characterized by progressive dystrophic calcification of aortic cusps. In the initial stages, the pathogenesis is similar to atherosclerosis, characterized by basement membrane disruption, inflammation, cell infiltration, lipid deposition, and calcification. Presence of osteopontin in calcified aortic valves suggests pathological calcification and bone formation in these calcified valves. Historical, experimental, genetic, and clinical evidences suggest that CAVD and atherosclerosis share the same pathological sequences with common risk factors. Understanding the two faces of atherosclerosis, the vascular and valvular, will help us to prevent progression of aortic sclerosis to aortic stenosis, by controlling modifiable risk factors and by initiating statin therapy in them. However, the knowledge about these preventive measures and drugs is scanty. In this review article, an attempt is made to unfurl the relation between atherosclerosis and CAVD

Dynamics of a prototype alkali-hydrogen-halide exchange reaction on an ab initio potential-energy surface

We report the results of a quasiclassical trajectory (QCT) study of a prototype alkali-hydrogen-halide exchange reaction Li+FH→LiF+H on an ab initio potential-energy surface for collinear as well as non-collinear geometries. A vibrational threshold equal to that of the barrier (21 kcal mol−1) noted for the collinear collisions is not found for the 3D collisions. Nevertheless, we do find that vibrational energy (V) is much more efficient than translational energy (T) in causing this reaction. There is a unique effect of reagent rotation on the reaction cross section (Sr) in that with increase in the rotational quantum number (J) from 0 through 15 for the vibrational state ν=2 at T=8.7 kcal mol−1, Sr decreases initially and then increases steeply. This is followed by a decline and a possible levelling off in St. We attribute the initial decline in Sr(J) to the disruption of the preferred alignment due to rotation. Further increase in rotation brings the molecule back into alignment and with much more rotational velocity, the molecule appears as a blur explaining the levelling off of Sr. Interestingly, for ν=0, there is a moderate rotational enhancement partly due to the increase in the number of product states becoming available with increase in the total energy. The effect of various forms of energy on other reaction attributes like product vibrational- and rotational-energy distribution and angular distribution has also been studied. Our calculated value of Sr as well as the product angular distribution and the coplanarity of the reaction are in good agreement with the exerimental results for ν=0, but they differ significantly from the QCT results of Shapiro and co-workers on their semi-empirical PES