Methicillin-Resistant Staphylococcus aureus Sepsis and Orbital Cellulitis Leading to a Combined Central Retinal Artery and Vein Occlusion: A Case Report.

Combined central retinal artery and vein occlusion (CCRAVO) is a rare entity characterized by features of tortuous retinal veins, retinal hemorrhage, optic disk edema and pallor, macula edema, cherry-red spot, and cotton-wool spots. The occurrence of CCRAVO in the adult population is often in the setting of systemic disease; while CCRAVO in the pediatric population is frequently associated with infection of the sinuses, preseptal cellulitis, or orbital cellulitis. It has been hypothesized that CCRAVO can result from methicillin-resistant Staphylococcus aureus (MRSA) sepsis-induced coagulation disturbances, orbital cellulitis, and even orbital compartment syndrome; however, there are insufficient reports of this complication. This case report sheds light on one such case with irreversible vision loss as a sequela.

Targeted Atrial Fibrillation Therapy and Risk Stratification Using Atrial Alternans.

Atrial fibrillation (AF) is the most persistent arrhythmia today, with its prevalence increasing exponentially with the rising age of the population. Particularly at elevated heart rates, a functional abnormality known as cardiac alternans can occur prior to the onset of lethal arrhythmias. Cardiac alternans are a beat-to-beat oscillation of electrical activity and the force of cardiac muscle contraction. Extensive evidence has demonstrated that microvolt T-wave alternans can predict ventricular fibrillation vulnerability and the risk of sudden cardiac death. The majority of our knowledge of the mechanisms of alternans stems from studies of ventricular electrophysiology, although recent studies offer promising evidence of the potential of atrial alternans in predicting the risk of AF. Exciting preclinical and clinical studies have demonstrated a link between atrial alternans and the onset of atrial tachyarrhythmias. Here, we provide a comprehensive review of the clinical utility of atrial alternans in identifying the risk and guiding treatment of AF.

Leflunomide-Induced Immune-Mediated Necrotizing Myopathy in a Patient With Rheumatoid Arthritis: A Case Report.

Immune-mediated necrotizing myopathy (IMNM) is a subtype of inflammatory myopathy that is characterized by proximal muscle weakness, markedly elevated serum creatine kinase, myopathic electromyographic findings, and muscle biopsies revealing necrosis or regeneration with sparse inflammatory infiltrate. IMNM tends to be idiopathic but has been associated with certain medications. This supports the possibility for other pharmacotherapies to induce IMNM-particularly leflunomide. Leflunomide is used in the treatment for rheumatoid arthritis and has been shown to induce autoimmune diseases-including autoimmune hepatitis and polymyositis. After an extensive review of history and workup of muscle weakness, we conclude that leflunomide induced an IMNM in our patient. As this is the first case of leflunomide-induced IMNM, it is important for clinicians to suspect an inflammatory myopathy in the setting of myositis while on leflunomide.

Advances in Cardiac Pacing: Arrhythmia Prediction, Prevention and Control Strategies.

Cardiac arrhythmias constitute a tremendous burden on healthcare and are the leading cause of mortality worldwide. An alarming number of people have been reported to manifest sudden cardiac death as the first symptom of cardiac arrhythmias, accounting for about 20% of all deaths annually. Furthermore, patients prone to atrial tachyarrhythmias such as atrial flutter and fibrillation often have associated comorbidities including hypertension, ischemic heart disease, valvular cardiomyopathy and increased risk of stroke. Technological advances in electrical stimulation and sensing modalities have led to the proliferation of medical devices including pacemakers and implantable defibrillators, aiming to restore normal cardiac rhythm. However, given the complex spatiotemporal dynamics and non-linearity of the human heart, predicting the onset of arrhythmias and preventing the transition from steady state to unstable rhythms has been an extremely challenging task. Defibrillatory shocks still remain the primary clinical intervention for lethal ventricular arrhythmias, yet patients with implantable cardioverter defibrillators often suffer from inappropriate shocks due to false positives and reduced quality of life. Here, we aim to present a comprehensive review of the current advances in cardiac arrhythmia prediction, prevention and control strategies. We provide an overview of traditional clinical arrhythmia management methods and describe promising potential pacing techniques for predicting the onset of abnormal rhythms and effectively suppressing cardiac arrhythmias. We also offer a clinical perspective on bridging the gap between basic and clinical science that would aid in the assimilation of promising anti-arrhythmic pacing strategies.