Advanced ablation strategies for management of post-surgical atrial arrhythmias.

Post-surgical arrhythmias include a wide range of arrhythmias occurring late after cardiac surgery and represent a complex substrate for catheter ablation either because of extended scar and remodeling or because of limited access to the area of interest. Novel image integration and ablation tools have made the catheter ablation in this population both feasible and successful. We review a structured approach to catheter ablation of post-surgical atrial arrhythmias in various patient cohorts including the most common congenital heart defects

Use of Case Histories to Enhance Practical Geotechnical Engineering

Mathematical models are constructed to describe the behavior of engineering systems in quantitative terms. During conceptualization stage of modelling several valid assumptions have to be made so as to make the model predict the behavior of the system as accurately as possible. Refinement of mathematical models need feed back from practice. Many practical cases are of interest in updating and enhancing quantitative judgment of geo-technical systems behavior. This paper envisages to present a few interesting cases where the situation forced true synthesis of theory and practice for innovation and advancement of practical geo-technical engineering

Effect of corrosion on flexural bond strength

Corrosion is one of the main causes affecting durability of structures. Corrosion effects on structures cannot be ignored and replaced. To understand the performance of structures there is a need to study the rate at which different corrosion levels occur. Hence the present investigation has been taken up to study the behaviour of NBS (National Bureau of Standard) beam specimens made up of Ordinary Portland Cement (OPC) and Portland Pozzolona Cement (PPC) concrete matrix were subjected to accelerated corrosion for different corrosion levels of 2.5 % to 10 % at 2.5 % interval. Results are compared with those for control beam specimen. It is observed that bond stress value decreases with the increase in corrosion levels. Also corrosion leads to the decline of load carrying capacity

Generation of large flavor mixing from radiative corrections

We provide a model independent criterion which would guarantee a large flavor mixing of two quasi-degenerate Majorana neutrinos at the low scale, irrespective of the mixing at the high scale. We also show that such a situation is realizable for a phenomenologically interesting range of parameters of the weak scale theory. We further show that for a similar condition to be implementable for the three generation case, the CP parity of one of the neutrinos needs to be opposite to that of the others.Comment: 14 pages RevTeX, 2 eps figures. Minor changes made, a few references adde

Effect of temperature on Rhizoctonia bataticola and dry root rot in chick pea

Chickpea dry root rot caused by Rhizoctonia bataticola (Taub.) Butler is a soil borne fungal pathogen causing significant yield losses due to change in environmental conditions. Influence of seven temperatures regimes (15°C, 20°C, 25°C, 30°C, 35°C, 40°C and 45°C) were tested on growth of R. bataticola isolates representing Madhya Pradesh, Karnataka, Maharashtra, Andhra Pradesh and Telangana states of India. The maximum mycelial growth was observed at 35ºC followed by 30 and 25ºC in all the isolates. The optimum temperature for dry root rot severity rating was at 35°C (8.5) followed by 30°C (7.9) followed by 25°C (7.0). Among the isolates, Telangana isolate was virulent and caused maximum disease severity

Fast fully automatic segmentation of the severely abnormal human right ventricle from cardiovascular magnetic resonance images using a multi-scale 3D convolutional neural network

Cardiac magnetic resonance (CMR) is regarded as the reference examination for cardiac morphology in tetralogy of Fallot (ToF) patients allowing images of high spatial resolution and high contrast. The detailed knowledge of the right ventricular anatomy is critical in ToF management. The segmentation of the right ventricle (RV) in CMR images from ToF patients is a challenging task due to the high shape and image quality variability. In this paper we propose a fully automatic deep learning-based framework to segment the RV from CMR anatomical images of the whole heart. We adopt a 3D multi-scale deep convolutional neural network to identify pixels that belong to the RV. Our robust segmentation framework was tested on 26 ToF patients achieving a Dice similarity coefficient of 0.8281±0.1010 with reference to manual annotations performed by expert cardiologists. The proposed technique is also computationally efficient, which may further facilitate its adoption in the clinical routine

Right atrial area and right ventricular outflow tract akinetic length predict sustained tachyarrhythmia in repaired tetralogy of Fallot

AIMS: Repaired tetralogy of Fallot (rtoF) patients are at risk of atrial or ventricular tachyarrhythmia and sudden cardiac death. Risk stratification for arrhythmia remains difficult. We investigated whether cardiac anatomy and function predict arrhythmia. METHODS: One-hundred-and-fifty-four adults with rtoF, median age 30.8 (21.9–40.2) years, were studied with a standardised protocol including cardiovascular magnetic resonance (CMR) and prospectively followed up over median 5.6 (4.6–7.0) years for the pre-specified endpoints of new-onset atrial or ventricular tachyarrhythmia (sustained ventricular tachycardia/ventricular fibrillation). RESULTS: Atrial tachyarrhythmia (n = 11) was predicted by maximal right atrial area indexed to body surface area (RAAi) on four-chamber cine-CMR (Hazard ratio 1.17, 95% Confidence Interval 1.07–1.28 per cm(2)/m(2); p = 0.0005, survival receiver operating curve; ROC analysis, area under curve; AUC 0.74 [0.66–0.81]; cut-off value 16 cm(2)/m(2)). Atrial arrhythmia-free survival was reduced in patients with RAAi ≥ 16 cm(2)/m(2) (logrank p = 0.0001). Right ventricular (RV) restrictive physiology on echocardiography (n = 38) related to higher RAAi (p = 0.02) and had similar RV dilatation compared with remaining patients. Ventricular arrhythmia (n = 9) was predicted by CMR RV outflow tract (RVOT) akinetic area length (Hazard ratio 1.05, 95% Confidence Interval 1.01–1.09 per mm; p = 0.003, survival ROC analysis, AUC 0.77 [0.83–0.61]; cut-off value 30 mm) and decreased RV ejection fraction (Hazard ratio 0.93, 95% Confidence Interval 0.87–0.99 per %; p = 0.03). Ventricular arrhythmia-free survival was reduced in patients with RVOT akinetic region length > 30 mm (logrank p = 0.02). CONCLUSION: RAAi predicts atrial arrhythmia and RVOT akinetic region length predicts ventricular arrhythmia in late follow-up of rtoF. These are simple, feasible measurements for inclusion in serial surveillance and risk stratification of rtoF patients

Myocardial Architecture, Mechanics, and Fibrosis in Congenital Heart Disease

Congenital heart disease (CHD) is the most common category of birth defect, affecting 1% of the population and requiring cardiovascular surgery in the first months of life in many patients. Due to advances in congenital cardiovascular surgery and patient management, most children with CHD now survive into adulthood. However, residual and postoperative defects are common resulting in abnormal hemodynamics, which may interact further with scar formation related to surgical procedures. Cardiovascular magnetic resonance (CMR) has become an important diagnostic imaging modality in the long-term management of CHD patients. It is the gold standard technique to assess ventricular volumes and systolic function. Besides this, advanced CMR techniques allow the acquisition of more detailed information about myocardial architecture, ventricular mechanics, and fibrosis. The left ventricle (LV) and right ventricle have unique myocardial architecture that underpins their mechanics; however, this becomes disorganized under conditions of volume and pressure overload. CMR diffusion tensor imaging is able to interrogate non-invasively the principal alignments of microstructures in the left ventricular wall. Myocardial tissue tagging (displacement encoding using stimulated echoes) and feature tracking are CMR techniques that can be used to examine the deformation and strain of the myocardium in CHD, whereas 3D feature tracking can assess the twisting motion of the LV chamber. Late gadolinium enhancement imaging and more recently T1 mapping can help in detecting fibrotic myocardial changes and evolve our understanding of the pathophysiology of CHD patients. This review not only gives an overview about available or emerging CMR techniques for assessing myocardial mechanics and fibrosis but it also describes their clinical value and how they can be used to detect abnormalities in myocardial architecture and mechanics in CHD patients

Advanced heart failure in adult congenital heart disease: the role of renal dysfunction in management and outcomes

Aims Previous studies in adult congenital heart disease (CHD) have demonstrated a link between renal dysfunction and mortality. However, the prognostic significance of renal dysfunction in CHD and decompensated heart failure (HF) remains unclear. We sought to assess the association between renal dysfunction and outcomes in adults with CHD presenting to our centre with acute HF between 2010 and 2021. Methods and results This retrospective analysis focused on the association between renal dysfunction, pre-existing and on admission, and outcomes during and after the index hospitalization. Chronic kidney disease (CKD) was defined as an estimated glomerular filtration rate <60 mL/min/1.73 m2. Cox regression analysis was used to identify the predictors of death post-discharge. In total, 176 HF admissions were included (mean age 47.7 ± 14.5 years, 43.2% females). One-half of patients had a CHD of great complexity, 22.2% had a systemic right ventricle, and 18.8% had Eisenmenger syndrome. Chronic kidney disease was present in one-quarter of patients. The median length of intravenous diuretic therapy was 7 (4–12) days, with a maximum dose of 120 (80–160) mg furosemide equivalents/day, and 15.3% required inotropic support. The in-hospital mortality rate was 4.5%. The 1- and 5-year survival rates free of transplant or ventricular assist device (VAD) post-discharge were 75.4% [95% confidence interval (CI): 69.2–82.3%] and 43.3% (95% CI: 36–52%), respectively. On multivariable Cox analysis, CKD was the strongest predictor of mortality or transplantation/VAD. Highly complex CHD and inpatient requirement of inotropes also remained predictive of an adverse outcome. Conclusion Adult patients with CHD admitted with acute HF are a high-risk cohort. CKD is common and triples the risk of death/transplantation/VAD. An expert multidisciplinary approach is essential for optimizing outcomes

Physico-chemical litter amendments and their impact on broiler chicks’ performance

The objective of the study was to compare the effects of alternative litter treatments on litter quality, growth, carcass traits and welfare of broiler chicks. Day old, commercial broiler chicks (180) having similar body weight range were randomly allocated to two different types of litter treatments, viz. treated litter at the rate of 120°C (T1) and litter treated with sodium bisulfate 25 g/sq. ft. (T2) along with the control group without any litter treatment (T0). Birds of all the treated groups performed better in terms of growth, feed intake and FCR, etc. Cake formation was frequent, highest in T0 followed by T1 and T2 groups which in turn affected the frequency of undesirably poor sanitary outlook of the birds. Significantly lower EPG (E. coli count per gram) count while a numerically lower microbial load of the faecal samples was noted in the T2 than T1 and control. This implied the change in the pH and acidification of litter materials prevented the growth of coccidia and microbial load in the litter, thus making the litter more suitable for bird welfare. It was concluded that chemical litter amendments had a beneficial effect on overall growth performance, carcass characteristics, health and welfare of broiler chicks