Scalable musculoskeletal model for dynamic simulations of upper body movement.

A musculoskeletal (MSK) model is a valuable tool for assessing complex biomechanical problems, estimating joint torques during motion, optimizing motion in sports, and designing exoskeletons and prostheses. This study proposes an open-source upper body MSK model that supports biomechanical analysis of human motion. The MSK model of the upper body consists of 8 body segments (torso, head, left/right upper arm, left/right forearm, and left/right hand). The model has 20 degrees of freedom (DoFs) and 40 muscle torque generators (MTGs), which are constructed using experimental data. The model is adjustable for different anthropometric measurements and subject body characteristics: sex, age, body mass, height, dominant side, and physical activity. Joint limits are modeled using experimental dynamometer data within the proposed multi-DoF MTG model. The model equations are verified by simulating the joint range of motion (ROM) and torque; all simulation results have a good agreement with previously published research.

Successful simultaneous retrieval of two dislodged and entangled intracoronary stents using distal balloon inflating technique.

Stent loss in coronary arteries is a rare complication of coronary intervention. Furthermore, the entanglement of a lost stent with a second previously deployed stent leading to a very complicated scenario has not been reported previously. In this case, we are presenting the first case report of a stent loss due to the entanglement of a stent with the ostial part of the second already deployed side branch stent leading to distortions of the second stent and entrapment. This is also the first case report describing the successful and simultaneous retrieval of both the lost and entangled deployed stents percutaneously using the distal inflating balloon technique.

Model-Based Mid-Level Regulation for Assist-As-Needed Hierarchical Control of Wearable Robots: A Computational Study of Human-Robot Adaptation.

The closed-loop human-robot system requires developing an effective robotic controller that considers models of both the human and the robot, as well as human adaptation to the robot. This paper develops a mid-level controller providing assist-as-needed (AAN) policies in a hierarchical control setting using two novel methods: model-based and fuzzy logic rule. The goal of AAN is to provide the required extra torque because of the robot's dynamics and external load compared to the human limb free movement. The human-robot adaptation is simulated using a nonlinear model predictive controller (NMPC) as the human central nervous system (CNS) for three conditions of initial (the initial session of wearing the robot, without any previous experience), short-term (the entire first session, e.g., 45 min), and long-term experiences. The results showed that the two methods (model-based and fuzzy logic) outperform the traditional proportional method in providing AAN by considering distinctive human and robot models. Additionally, the CNS actuator model has difficulty in the initial experience and activates both antagonist and agonist muscles to reduce movement oscillations. In the long-term experience, the simulation shows no oscillation when the CNS NMPC learns the robot model and modifies its weights to simulate realistic human behavior. We found that the desired strength of the robot should be increased gradually to ignore unexpected human-robot interactions (e.g., robot vibration, human spasticity). The proposed mid-level controllers can be used for wearable assistive devices, exoskeletons, and rehabilitation robots.

Assistive Sliding Mode Control of a Rehabilitation Robot with Automatic Weight Adjustment.

There are approximately 13 million new stroke cases worldwide each year. Research has shown that robotics can provide practical and efficient solutions for expediting post-stroke patient recovery. This simulation study aimed to design a sliding mode controller (SMC) for an end-effector-based rehabilitation robot. A genetic algorithm (GA) was designed for automatic controller weight adjustment. The optimal weights were obtained by minimizing a cost function comprising the end-effector position error, robot input, robot input-rate, and patient input. To promote safe tuner optimization, a model of the human arm was incorporated to generate the human joint torque. A computed-torque proportional derivative controller (CTPD) was designed for the human arm to approximate the central nervous system (CNS) motor control. This controller was adjusted to simulate rehabilitation effects and patient adaptation. The tuner was optimized for a trajectory tracking task with an assistive high-level control scheme. The simulation results showed lower cost compared to seven manual weight settings. The optimal weights provided good tracking performance and suitable robot inputs. This research provides a framework to conduct various simulations before testing our controller on human subjects. The preliminary results of this study will be used as the starting point for online adaptive controller tuning, which will be examined in our future research.

A preliminary study on the radiation dose reduction during catheterization procedures using simple partial patient shielding.

Reduction in X-ray exposure during cardiac catheterization is important to reduce radiation risks to operators and personnel. Reducing scattered radiation from the patient can achieve this goal. The goal of this study was to evaluate the reduction in radiation using simple partial shielding of patients undergoing cardiac catheterization. By putting a lead-based apron on the lower extremities of patients undergoing cardiac catheterization, we analyzed the reduction in total radiation dose with and without this shielding. One hundred and twelve patients were divided into two groups. In one group, the protective lead-based apron was put on the lower extremities of patients. Another group did not have any shielding. Total duration of angiography was 332 minutes and 45 seconds in the first group and 269 minutes and 10 seconds in the second group. The total radiation exposure was 33 µGy in the first group vs 606 µGy in the second group. Despite higher exposure time, total radiation dose was 22 times lower in the simple shielded group. Our simple method without any additional cost can significantly reduce radiation exposure in the cardiac catheterization laboratory.

A forgotten diagnosis in right heart failure: A case report and literature review.

Carcinoid heart disease is a well-known complication of carcinoid syndrome that affects morbidity and mortality. Carcinoid heart disease may be asymptomatic in the early stages; therefore, patients with carcinoid syndrome should be screened to prevent misdiagnosis.

A rare presentation of an elderly patient with acute lymphocytic leukemia and platelet count of zero associated with ST-elevation myocardial infarction, pulmonary thromboembolism in the setting of SARS-CoV 2: a case report.

BACKGROUND: Novel coronavirus disease 2019 (COVID-19) is known to lead not only to severe acute respiratory syndrome, but also can result in thromboembolic events in both the venous and the arterial circulation by inducing coagulation disorders. The potential causes of coagulopathy are inflammation, platelet activation, endothelial dysfunction, and stasis. The thrombotic events including pulmonary embolism, deep venous thrombosis as well as intracatheter thrombosis are more likely to develop in patients infected with severe form of SARS-CoV-2 who are admitted to ICU. Furthermore, these events contribute to multi-organ failure. CASE PRESENTATION: Herein, we report a case of an immunocompromised COVID-19 elderly patient with acute lymphocytic leukemia who developed myocardial infarction with ST elevation in the setting of acute pulmonary thromboembolism in the presence of zero platelet count. Despite successful urgent coronary revascularization and platelet transfusion, the patient eventually died after failed resuscitation efforts. CONCLUSION: Patients with COVID-19 infection are at a greater risk of developing cardiovascular complications, but their appropriate management can decrease the risk of fatal events. Coronary thrombosis associated with pulmonary thromboembolism in the setting of thrombocytopenia is a rare and a complex to manage condition. Significance of single antiplatelet agent in STEMI with thrombocytopenia merits further studies. According to expert opinions and literature reviews, we must avoid dual antiplatelet therapy in these patients and keep platelet transfusion as a standard therapy to avoid drastic bleeding complications.

Novel Product for the Management of Coronary Ruptures Happening during Percutaneous Coronary Interventions.

Coronary artery perforation during percutaneous coronary interventions is a rare but dreaded complication. One of the treatment methods for this complication is the injection of an obliterating material into the ruptured vessel. We will introduce a novel material named "Spongostan" for embolization with significant advantages over available treatment options.

Multilayered non-uniform atomic force microscope piezoelectric microcantilever control and vibration analysis considering different excitation based on the modified couple stress theory.

Atomic force microscope (AFM) is one of the most powerful tools for surface scanning, force measurement, and nano-manipulation. To improve its performance, vibration and control of AFM micro-cantilever (MC) should be studied. Hysteresis, as an undesired phenomenon affecting vibration amplitude and phase, is also another important issue to be examined. In this paper, vibration analysis and control of a ZnO non-uniform multi-layered piezoelectric MC has been investigated in non-contact mode. A modified couple stress theory has been used to obtain the strain energy for modeling the MC. In order to control the amplitude, a sliding mode controller (SMC) has been utilized on AFM, due to its application in uncertain and nonlinear systems. For applying the control signal, two methods of piezo and base actuation are studied. The results are compared with proportional integral derivative (PID) control method and it is demonstrated that SMC method reduces the control input close to the surface and increases the accuracy near the surface. In addition to MC control, hysteresis amplitude and phase differences are investigated by applying the Prandtl-Ishlinskii model. Also, surface topography is studied with hysteresis. The simulations show backward phase difference and an increase in amplitude, accordingly.

Coronavirus Disease 2019 and Catheterisation Laboratory Considerations: "Looking for Essentials".

The current coronavirus disease 2019 (COVID-19) outbreak is a significant health crisis that impacts every healthcare system worldwide, and has led to a dramatic change in dealing with different diseases during the pandemic. Interventional cardiologists are frontline workers who deal with many cardiovascular emergencies, either in patients with proven COVID-19 or in suspected cases. Many heart associations worldwide are currently setting appropriate recommendations for the management of emergency cardiac interventions. In this expert opinion, the authors highlight the essential requirements in the cardiac catheterisation laboratory during the COVID-19 pandemic.

Left Atrial Appendage Aneurysm.

Left atrial appendage aneurysms (LAAA) are extremely rare. This condition is usually diagnosed incidentally or after the occurrence of thrombotic events or cardiac tachyarrhythmias in the second to fourth decades of life. It can predispose to hazardous adverse events, including atrial fibrillation, myocardial infarction, and systemic thromboembolism. We report a case of LAAA in a 68-year-old woman presenting with atypical chest pain, exertional dyspnea, and episodes of sudden-onset palpitation. Aneurysmectomy with the patient under cardiac arrest with cardiopulmonary bypass was performed. In addition, we explore the diagnosis, management, and prognosis of this entity through a meticulous literature review.

Unusual case of aortic coarctation complicated by mycotic pseudoaneurysm and bicuspid aortic valve endocarditis.

Coarctation complicated with mycotic pseudo-aneurysm is very rare. We are reporting a case of a 26-year-old man suffered from this pathology. As the incidence of mycotic pseudo-aneurysm is very rare in patients with aortic coarctation, the choice of this pathology for a patient presenting with unexplained fever is the only way to reduce the mortality risk.

Positive Brugada challenge test in V1 R-V3 R as a predictor of malignant prognosis in Brugada patients.

BACKGROUND: The Brugada syndrome is a heterogeneous genetic disease that predisposes to life-threatening ventricular tachyarrhythmias and sudden cardiac death (SCD). The only proven way to prolong the survival of patients with Brugada syndrome is to implant an implantable cardioverter-defibrillator (ICD). This should be implanted for high-risk patients only. METHOD: The patients with type 2 or 3 Brugada ECG pattern were selected for the study. We evaluated 126 patients with Brugada type ECG patterns. Nineteen patients had positive response. Those who had positive result in right side located leads had poorer prognosis. CONCLUSION: Positive flecainide challenge test in right side located pericordial leads can be used as a predictor of poor prognosis in Brugada patients. This can be evaluated in another research for its role in the implantation of ICD. Also, the oral flecainide is not sensitive enough to rule out the presence of Brugada syndrome and it should not be trusted as a screening test for suspected cases.

A prospective observational study of paediatric cardiac surgery outcomes in a postoperative intensive care unit in Iran.

OBJECTIVE: To evaluate the incidence of complications, morbidity and mortality, and the associated risk factors with mortality at a Paediatric Cardiology Intensiv Care Unit of a developing country. METHODS: The prospective observational study was conducted at Shahid Modarres Hospital, Tehran, Iran, from August 2009 to July 2010. A total of 202 patients were monitored from the time they entered the Paediatric Cardiology Intensive Care Unit till their final discharge. SPSS 16 was used for statistical analysis and p < or = 0.05 was considered statistically significant. RESULTS: Of the total, 107 (53%) were male and 95 (47%) were female. The mean age of the patients was 4.5 +/- 4.9 years (range: 2 days to 18 years). Among the patients 59 (29.2%) had complications and 25 (12.37%) of them died. A total of 177 (87.6%) survived and were discharged. Infants (p = 0.012), cyanotic congenital heart disease (p = 0.002), longer duration of cardiopulmonary bypass (p = 0.027), longer aortic cross-clamp time (p = 0.038), longer mechanical ventilation time (p < 0.006), and early post-operative period (p = 0.05) were associated factors for mortality. According to regression analysis, cyanotic congenital heart disease, longer intubation time, and early post-operative period were major factors for mortality (p = 0.01, p < 0.001, and p = 0.001) respectively. CONCLUSION: Critically ill cyanotic young infants in the first 24 hours after operation experienced high mortality. Prolonged mechanical ventilation was also associated with high mortality.

A rare case of congenital heart disease with bifid cardiac apex: a unique finding in left ventricle.

Bifid cardiac apex is a rare anomaly of human hearts. We report of the case of a 34-year-old man with a previous history of ventricular septal defect (VSD) and subvalvular pulmonary stenosis. He had undergone pulmonary commissurotomy and VSD closure 22 years before he was referred to our center for evaluation of progressive dyspnea. Transthoracic echocardiography revealed atrial septal defect (ASD), multiple VSDs, severe pulmonary regurgitation, and a bifid cardiac apex. The patient was referred for re-do surgery for ASD and VSD closure along with pulmonary valve replacement, but he refused the surgery.

Echocardiographic findings in thalassemia major: a case report and literature review.

We introduce a 28-year-old woman with Thalassemia major whose clinical assessment, including two-dimensional Doppler echocardiography demonstrated severe left ventricular hypertrophy with severe biventricular enlargement and systolic dysfunction as well as severe diastolic dysfunction. We hereby address these issues from an echocardiographic point of view.