Numerical and experimental investigation of heat transfer enhancement in double tube heat exchanger using nail rod inserts.

The Double-tube heat exchanger (DTHX) is widely favored across various industries due to its compact size, low maintenance requirements, and ability to operate effectively in high-pressure applications. This study explores methods to enhance heat transfer within a DTHX using both experimental and numerical approaches, specifically by integrating a nail rod insert (NRI). A steel nails rod insert, 1000 mm in length, is introduced into the DTHX, which is subjected to turbulent flows characterized by Reynolds numbers ranging from 3200 to 5700.

Experimental Investigation on the Energy and Exergy Efficiency of the Vacuum Membrane Distillation System with Its Various Configurations.

This paper addresses a retrofitting vacuum membrane distillation (VMD) setup to reduce the accumulated pressure inside the permeated side. This modification is necessary to extend the operation of the VMD to extreme operation conditions of higher hot water temperatures. This modification, denoted as a hybrid configuration, proposes the injection of a cold water stream into the VMD cell without mixing it with the permeate.

Numerical investigation of the effect of rectangular and semicircular cavities filled with phase change materials installed on the solar wall.

The use of alternative energy sources, particularly solar energy, in buildings is rising and spreading around the globe. In this paper, a solar wall is analyzed using a numerical method. On the wall, a number of obstacles are placed in two shapes, rectangular (REC) and semicircular (SEC).

Anomalous Coronary Arteries: A Cause for Malignant Arrhythmias.

Anomalous aortic origin of a coronary artery (AAOCA) is a congenital condition that can lead to sudden cardiac death (SCD), particularly among young individuals. The cause of SCD is thought to be ischemia, primarily related to the course of the anomalous coronary artery. Surgical intervention, such as unroofing or coronary revascularization, is the preferred management modality for patients with evidence of ischemia or concomitant fixed obstruction.

The Utility of Sodium Channel Provocation in Unexplained Cardiac Arrest Survivors and Electrocardiographic Predictors of Ventricular Fibrillation Recurrence.

Background: The implications of a drug-induced type 1 Brugada ECG pattern following sodium channel blocker provocation (SCBP) are not fully understood.

Methods: Baseline clinical and ECG data were obtained from consecutive unexplained cardiac arrest survivors undergoing SCBP at 3 centers. A further 15 SCBP positive (SCBP+) unexplained cardiac arrest survivors were recruited from 3 additional centers to explore ventricular fibrillation recurrence.

Numerical Analysis of the Effect of Nanoparticles Size and Shape on the Efficiency of a Micro Heatsink.

In this paper, two novel micro heat sinks (MHSs) were designed and subjected to thermal analysis using a numerical method. The fluid used was Boehmite alumina-water nanofluid (NFs) with high volume fractions (VOFs). Studies were conducted to determine the influence of a variety of nanoparticle (NP) shapes, such as platelet brick, blade, cylinder, and Os.

Investigating the Effect of Tube Diameter on the Performance of a Hybrid Photovoltaic-Thermal System Based on Phase Change Materials and Nanofluids.

The finite element (FEM) approach is used in this study to model the laminar flow of an eco-friendly nanofluid (NF) within three pipes in a solar system. A solar panel and a supporting phase change material (PCM) that three pipelines flowed through made up the solar system. An organic, eco-friendly PCM was employed.

Tacrolimus-Induced Diffuse Coronary Artery Spasm.

Prinzmetal angina, also known as vasospastic angina, is defined as an intermittent focal or diffuse coronary artery narrowing, which is often associated with transient ST-segment elevation on an electrocardiogram. Also, it could be associated with an atherosclerotic lesion at the site of the spasm. Vasospastic angina might be induced by medications, most commonly with cocaine and other examples which include catecholamines such as epinephrine, norepinephrine, isoproterenol, dopamine, and dobutamine.

Performance Comparison of Cross- and Forward-Flow Configurations for Multiple-Effect Vacuum Membrane Distillation.

This work addresses retrofitting the infrastructure of multiple-effect vacuum membrane distillation (V-MEMD) units by using cross-flow configuration (CFC). In this configuration, the feed water is evenly divided and distributed over the effects. In this case, the feed water stream for each effect is kept at a high temperature and low flow rate.

The Quality of Life in Patients With Implantable Cardiac Devices: A Single-Center Cross-Sectional Study.

Background Cardiovascular diseases (CVDs) and their complications are one of the most common causes of death worldwide. Implantable cardiac assistive devices (CADs) play a significant role in preventing dreadful outcomes, and the complication rate of these implanting procedures is minimal. These cardiac devices require some adaptation and could affect the patients' quality of life psychosocially and financially.

Design and Energy Requirements of a Photovoltaic-Thermal Powered Water Desalination Plant for the Middle East.

Seawater or brackish water desalination is largely powered by fossil fuels, raising concerns about greenhouse gas emissions, particularly in the arid Middle East region. Many steps have been taken to implement solar resources to this issue; however, all attempts for all processing were concentrated on solar to electric conversion. To address these challenges, a small-scale reverse-osmosis (RO) desalination system that is in part powered by hybrid photovoltaic/thermal (PVT) solar collectors appropriate for a remote community in the Kingdom of Saudi Arabia (KSA) was designed and its power requirements calculated.

Glycated Haemoglobin and Outcomes of Percutaneous Coronary Intervention Among Type Two Diabetic Patients in Saudi Arabia.

Background: Glycated haemoglobin (HbA1c) is a marker that reflects the control of diabetes mellitus (DM) over a three-month period. We sought to compare cardiovascular outcomes of diabetic patients with and without controlled levels of HbA1c post percutaneous coronary intervention (PCI) presenting to King Faisal Cardiac Center.   Methods: A retrospective single-center study of all patients with type two DM who were treated with PCI during the period between January 2015 and January 2018.

Para-Hisian Pacing During Sinus Rhythm: Establishing Threshold Values to Distinguish Nodal From Septal Pathway Conduction.

Objectives: This study sought to identify minimum threshold values below which conduction over the atrioventricular (AV) node would be unexpected.

Background: Para-Hisian pacing is used to evaluate for the presence of a septal accessory pathway (AP); however, threshold values to differentiate nodal from AP conduction are unknown.

Methods: The authors performed high- and low-output para-Hisian pacing during sinus rhythm to capture the His and para-Hisian ventricular myocardium (H+V) and para-Hisian ventricular myocardium (V) alone, respectively.

Double chamber cross-talk, the ultimate double-cross.

Cross-talk is a well-described phenomenon in a dual-chamber cardiovascular implantable electronic device. Far-field ventricular events are more commonly sensed in the atrial channel, the reverse is uncommon, and seeing both at the same time has never been reported. We present a case of double cross-talk in a dual-chamber Medtronic ® implantable cardioverter-defibrillator.

Coronary vasospasm-induced polymorphic ventricular tachycardia: a case report and literature review.

Introduction: Coronary vasospasm is an uncommon but important cause of myocardial ischaemia and ventricular arrhythmias.

Case Presentation: In this report, we present a striking example of vasospasm manifesting as ST-segment elevation and ventricular tachycardia on Holter monitoring. Later, spasm occurred during a procainamide challenge performed for suspected Brugada syndrome.

Health Care Utilization After Ventricular Tachycardia Ablation: A Propensity Score-Matched Cohort Study.

Background: Catheter ablation of ventricular tachycardia (VT) can reduce the burden of ventricular arrhythmia (VA) but its effect on health care utilization and costs after such therapy is poorly known. We sought to compare the rates of cardiovascular (CV)-related hospitalizations, survival, and health care costs in patients with recurrent VT treated either with VT ablation or with medical therapy.

Methods: One-hundred implantable cardioverter-defibrillator patients with structural heart disease who underwent VT ablation were included.

Cardiac resynchronization is pro-arrhythmic in the absence of reverse ventricular remodelling: a systematic review and meta-analysis.

Aims: Cardiac resynchronization therapy (CRT) has been shown to reduce mortality and heart failure (HF) hospitalization but its effects on the rate of ventricular arrhythmias (VAs) appears to be neutral. We hypothesize that CRT with LV epicardial stimulation is inherently pro-arrhythmic and increases VA rates in the absence of reverse ventricular remodelling while conferring an anti-arrhythmic effect in mechanical responders.

Methods And Results: In this systematic review and meta-analysis, we considered retrospective cohort, prospective cohort, and randomized controlled trials comparing VA rates between cardiac resynchronization therapy-defibrillator (CRT-D) non-responders, CRT-D responders and those with implantable cardioverter-defibrillator (ICD) only.

Should Single-Coil Implantable Cardioverter Defibrillator Leads Be Used in all Patients?

The historical preference for dual-coil implantable cardioverter defibrillator leads stems from high defibrillation thresholds associated with old device platforms. The high safety margins generated by contemporary devices have rendered the modest difference in defibrillation efficacy between single- and dual-coil leads clinically insignificant. Cohort data demonstrating worse lead extraction outcomes and higher all-cause mortality have brought the incremental utility of an superior vena cava coil into question.

Mortality Implications of Appropriate Implantable Cardioverter Defibrillator Therapy in Secondary Prevention Patients: Contrasting Mortality in Primary Prevention Patients From a Prospective Population-Based Registry.

Background: We sought to examine the mortality impact of appropriate implantable cardioverter defibrillator (ICD) therapy between patients who received ICD for primary versus secondary prevention purposes.

Methods And Results: From a prospective, population-based registry, we identified 7020 patients who underwent de novo ICD implantation between February 2007 and May 2012 in Ontario, Canada. The primary outcome was all-cause mortality.

Right Ventricular Ejection Fraction Is Incremental to Left Ventricular Ejection Fraction for the Prediction of Future Arrhythmic Events in Patients With Systolic Dysfunction.

Background: Left ventricular ejection fraction remains the primary risk stratification tool used in the selection of patients for implantable cardioverter defibrillator therapy. However, this solitary marker fails to identify a substantial portion of patients experiencing sudden cardiac arrest. In this study, we examined the incremental value of considering right ventricular ejection fraction for the prediction of future arrhythmic events in patients with systolic dysfunction using the gold standard of cardiovascular magnetic resonance.

Objective criteria for septal fibrosis in non-ischemic dilated cardiomyopathy: validation for the prediction of future cardiovascular events.

Background: Expert subjective reporting of mid-wall septal fibrosis on late gadolinium enhancement (LGE) images has been shown to predict major cardiovascular outcomes in patients with non-ischemic dilated cardiomyopathy (NIDCM). This study aims to establish objective criteria for non-experts to report clinically relevant septal fibrosis and compare its performance by such readers versus experts for the prediction of cardiovascular events.

Methods: LGE cardiovascular magnetic resonance (CMR) was performed in 118 consecutive patients with NIDCM (mean age 57 ± 14, 42 % female) and the presence of septal fibrosis scored by expert readers.

Delayed Tamponade after Traumatic Wound with Left Ventricular Compression.

Delayed cardiac tamponade after a penetrating chest injury is a rare complication. The clinical diagnosis of tamponade is facilitated with imaging. We present a case report of a 23-year-old male who was brought to emergency after multiple stab wounds to the chest.

Mobile Intracardiac Mass after Inguinal Hernia Repair: An Unresolved Treatment Dilemma.

Right heart thrombi (RHT) are rare but well-described entity in literature. Their isolation has been considered as confirmatory for the diagnosis of venous thromboembolism (VTE). Even though their isolation aids the diagnosis, physicians are faced with a difficult management dilemma giving the paucity of data to support any treatment decision.