Rare variants in cardiomyopathy genes predispose to cardiac injury in severe COVID-19 patients of African or Hispanic ancestry.

In one of the earliest reports from China during COVID-19, it was noted that over 20% of patients hospitalized with the disease had significant elevations of troponin, a marker of myocardial tissue damage, that put them at a higher risk. In a hypothesis-independent whole exome sequencing (WES) study in hospitalized COVID-19 patients of diverse ancestry, we observed putative enrichment in pathogenic variants in genes known to be involved in the pathogenesis of cardiomyopathy. This observation led us to hypothesize that the observed high morbidity and mortality in these patients might be due to the presence of rare genetic factors that had previously been silent but became relevant as a consequence of the severe stress inflicted by an infection with SARS-CoV-2.

Cardiac implantable device interrogation in left ventricular systolic dysfunction reveals physiologic abnormalities prior to symptom onset in COVID-19: a case series.

Background: COVID-19 has affected individuals across the globe, and those with cardiac implantable electronic devices (CIEDs) likely represent a high-risk group. These devices can be interrogated to reveal information about the patient activity, heart rate parameters, and respiratory rate.

Case Summary: Four patients with CIEDs and left ventricular dysfunction were admitted to a single institution for COVID-19 infection.

Correlation between severity of obesity and mortality in cardiogenic shock.

Introduction: Cardiogenic shock (CS) is associated with high mortality despite the development of risk stratification tools and new treatment strategies. Obesity, although a risk factor for cardiovascular disease, is not included in current risk stratification tools for CS. A relationship between mortality and obesity has only been shown in subsets populations of CS; there is not yet a clear relationship between severity of obesity and all-cause CS.

Failing Hearts Are More Vulnerable to Sympathetic, but Not Vagal Stimulation-Induced, Atrial Fibrillation-Ameliorated with Dantrolene Treatment.

Background: Both vagal (VS) and sympathetic (SS) stimulations can increase atrial fibrillation (AF) inducibility, with VS being known as more arrhythmogenic in normal hearts. Heart failure (HF) results in autonomic dysfunction (characterized by sympathetic activation and vagal withdrawal) and is associated with an increased AF incidence. This study investigated whether failing hearts, compared with normal control hearts, respond differently to autonomic stimulation-induced AF arrhythmogenesis and the effect of dantrolene on SS-enhanced AF in HF.

Reduced epicardial vagal nerve density and impaired vagal control in a rat myocardial infarction-heart failure model.

Background: Autonomic remodeling, characterized by sympathetic activation and vagal withdrawal, contributes to heart failure (HF) progression. However, the exact mechanism(s) responsible for vagal withdrawal in HF remain(s) unclear, and whether HF causes epicardial autonomic nerve remodeling is unknown.

Methods And Results: Myocardial infarction (MI) was produced in 14 Sprague-Dawley rats, and 10 sham surgery rats served as the control.

A Gram Stain Hands-On Workshop Enhances First Year Medical Students' Technique Competency in Comprehension and Memorization.

Background: Laboratory diagnostic tests have an essential role in patient care, and the increasing number of medical and health professions schools focusing on teaching laboratory medicine to pre-clinical students reflects this importance. However, data validating the pedagogical methods that best influence students' comprehension and interpretation of diagnostic tests have not been well described. The Gram stain is a simple yet significant and frequently used diagnostic test in the clinical setting that helps classify bacteria into two major groups, Gram positive and negative, based on their cell wall structure.

Electrical synaptic transmission in developing zebrafish: properties and molecular composition of gap junctions at a central auditory synapse.

In contrast to the knowledge of chemical synapses, little is known regarding the properties of gap junction-mediated electrical synapses in developing zebrafish, which provide a valuable model to study neural function at the systems level. Identifiable "mixed" (electrical and chemical) auditory synaptic contacts known as "club endings" on Mauthner cells (2 large reticulospinal neurons involved in tail-flip escape responses) allow exploration of electrical transmission in fish. Here, we show that paralleling the development of auditory responses, electrical synapses at these contacts become anatomically identifiable at day 3 postfertilization, reaching a number of ∼6 between days 4 and 9.