ACTN3 R/X gene polymorphism across ethnicity: a brief review of performance gene

Sport Sciences for Health - Alpha-actinin-3 (ACTN3) gene is one of the most extensively investigated genes associated with human physical performance. The ACTN3 gene via ACTN3 R/X gene polymorphism...     

Percutaneous Left Atrial Appendage Closure Devices

Purpose of Review

Atrial fibrillation (AF) is the most common arrhythmia in humans. It is a major cause of morbidity and mortality as it impairs cardiac function and is a major risk of embolic stroke. Traditionally, thromboembolic risk of AF has been treated with system anticoagulation with intravenous, intramuscular, or oral anticoagulants. Although the novel oral anticoagulants (NOACs) have revolutionized stroke risk reduction in AF patients, they are associated with a significant risk of bleeding and may be contraindicated in certain patients. Embolic events in AF typically originate from thrombi that form within the left atrial appendage (LAA), especially in nonvalvular AF. Both surgical and percutaneous LAA closure techniques have been devised as alternatives to systemic anticoagulation. As surgical LAA closure is typically performed as an adjunct to other cardiac surgeries, the amount of eligible patients for this type of therapy may be limited.

Recent Findings

Excluding the LAA from the systemic circulation may reduce the risk of thromboembolism in AF. Recent technologic advances have led to the development of several percutaneously delivered devices that can occlude or exclude the LAA from systemic circulation. These devices may be purely endocardially delivered such as the Watchman (Boston Scientific, Maple Grove, MN) and Amulet (St. Jude Medical, Minneapolis, MN), or both endocardially and pericardially delivered such as the Lariat (Sentre-HEART, Palo Alto, CA). During Amulet and Watchman procedures, a transseptally delivered device composed of nitinol is placed in the LAA orifice, subsequently excluding the LAA from the systemic circulation. In the Lariat procedure, a magnet link is created between a transseptally delivered endocardial wire and epicardially delivered pericardial wire, followed by epicardial suture ligation of the LAA. Their use is steadily increasing in worldwide either through routine clinical use of approved devices or within clinical trials.

Summary

In this review, we describe the various devices available for percutaneous LAA closure, and the indispensable role of real-time transesophageal echocardiography in the periprocedural assessment and intraprocedural guidance of percutaneous LAA occlusion procedures.

     

Mitral valve Libman-Sacks endocarditis visualized by real time three-dimensional transesophageal echocardiography

Libman-Sacks endocarditis (LSE) is a common manifestation of valve disease in antiphospholipid syndrome. Mitral valve LSE is characterized by verrucous vegetations on the atrial surfaces of valve leaflets. In this report, mitral valve LSE was visualized by real time 3D transesophageal echocardiography (TEE). 3D TEE provides a unique en face view of the mitral valve akin to a surgical or autopsy view that allows for an accurate determination of the size, shape, and location of the vegetations.     

Decellularized extracellular matrix gelloids support mesenchymal stem cell growth and function in vitro

Volumetric muscle loss (VML) injuries are irrecoverable due to a significant loss of regenerative elements, persistent inflammation, extensive fibrosis, and functional impairment. When used in isolation, previous stem cell and biomaterial‐based therapies have failed to regenerate skeletal muscle at clinically relevant levels. The extracellular matrix (ECM) microenvironment is crucial for the viability, stemness, and differentiation of stem cells. Decellularized‐ECM (D‐ECM) scaffolds are at the forefront of ongoing research to develop a viable therapy for VML. Due to the retention of key ECM components, D‐ECM scaffolds provide an excellent substrate for the adhesion and migration of several cell types. Mesenchymal stem cells (MSCs) possess regenerative and immunomodulatory properties and are currently under investigation in clinical trials for a wide range of medical conditions. However, a major limitation to the use of MSCs in clinical applications is their poor viability at the site of transplantation. In this study, we have fabricated spherical scaffolds composed of gelatin and skeletal muscle D‐ECM for the adhesion and delivery of MSCs to the site of VML injury. These spherical scaffolds termed “gelloids” supported MSC survival, expansion, trophic factor secretion, immunomodulation, and myogenic protein expression in vitro. Future studies would determine the therapeutic efficacy of this approach in a murine model of VML injury.     

Atrial fibrillation ablation in patients with known sludge in the left atrial appendage

Purpose

Transesophageal echocardiography (TEE) is routinely used to assess for thrombus in the left atrium (LA) and left atrial appendage (LAA) in patients undergoing atrial fibrillation (AF) ablation. However, little is known about the outcome of AF ablation in patients with documented LAA sludge. We hypothesize that AF ablation can be performed safely in a proportion of patients with sludge in the LAA and may have a significant benefit for these patients.

Methods

We performed a retrospective analysis of all patients undergoing AF ablation at New York University Langone Medical Center (NYULMC) from January 1st 2011 to June 30, 2013. Patients with sludge found on their TEE immediately prior to AF ablation were identified and followed for stroke, AF recurrence, procedural complications, major bleeding, or death.

Results

Among 1,076 patients who underwent AF ablation, 8 patients (mean age 69?±?13 years; 75 % men) with sludge were identified. Patients with sludge in their LAA had no incidence of early or late occurrence of stroke during mean follow-up of 10 months. One patient had a left groin hematoma, and two patients had atrial tachycardias that needed a repeat ablation. TEE at the time of repeat ablation demonstrated the presence of spontaneous echo contrast (smoke) and resolution of sludge. There were no deaths.

Conclusion

In a cohort of eight patients with LAA sludge who underwent AF ablation, no significant thromboembolic events occurred during or after the procedure. AF ablation can be performed safely and may be beneficial in these patients. Larger studies are warranted to better determine the most appropriate management route.     

Real-time three-dimensional transesophageal echocardiography in transcutaneous, catheter-based procedures for repair of structural heart diseases

We review the use of real-time three-dimensional transesophageal echocardiography (RT3D-TEE) in guiding percutaneous catheter-based procedures to repair structural heart defects. The utility of this novel imaging technique in percutaneous mitral valve repair and valvuloplasty, aortic valve insertion, device closure of atrial and ventricular septal defects, obliteration of the left atrial appendage, and pulmonary vein ablation is described. The main advantages of RT3D-TEE lie in its ability to visualize the entire length of intracardiac devices, including their tips, and to demonstrate their relationship to cardiac structures, to provide en face views of cardiac structures (such as the interatrial septum and the mitral valve) that are unobtainable in real time by any other imaging technique, and to allow for continuous monitoring during the procedure. It is likely that RT3D-TEE will become the standard of care for guidance of percutaneous, catheter-based procedures.