Our results demonstrate strands of Cx43 and Cx40 positive atrial cells protruding into the Cx45 positive nodal area and a band of connective tissue largely separating the nodal and atrial tissue. This organization of the mouse SA node provides a structural substrate that both shields the nodal area from the hyperpolarizing influence of the atrium and allows fast action potential conduction from the nodal area into the surrounding atrium.

Intercellular communication between cells of the vessel wall is established by a combination of diffusion and convection of humoral and endothelial factors in the extracellular fluid or by direct intercellular contacts present in the form of gap junctions composed of proteins called connexins. At least connexin (Cx)37, Cx40 and Cx43 are expressed in the vessel wall, but disparate findings with regard to the cell specific localisation of connexins in the vasculature indicate that the distribution of connexins may be species and vessel specific. Moreover, differences in expression exist between cells in culture and tissue sections. We performed an inventory immunohistochemical study on the localisation of Cx37, Cx40 and Cx43 on tissue sections of the bovine, micropig and rat aorta and coronary system, which represent morphologically and functionally different types of vessels in the arterial system. We could observe Cx40 labelling most commonly, although with various intensities, between endothelial and smooth muscle cells of the species studied, with the exception of rat aortic smooth muscle cells. The distribution of Cx43 is more differentiated and mostly confined to smooth muscle cells, although it can be detected scarcely between endothelial cells. Cx37, when detectable, is predominantly expressed between endothelial cells in a heterogeneous pattern. We conclude that Cx40 is the constitutive vascular gap junction protein in situ and guarantees cell coupling between cells in the vessel wall. The differentiated distribution of both Cx37 and Cx43 suggests they are involved in more dynamic processes.

Aims Patients with cardiac disease are considered high risk for poor outcomes following hospitalization with COVID-19. The primary aim of this study was to evaluate heterogeneity in associations between various heart disease subtypes and in-hospital mortality. Methods and results We used data from the CAPACITY-COVID registry and LEOSS study. Multivariable Poisson regression models were fitted to assess the association between different types of pre-existing heart disease and in-hospital mortality. A total of 16 511 patients with COVID-19 were included (21.1% aged 66–75 years; 40.2% female) and 31.5% had a history of heart disease. Patients with heart disease were older, predominantly male, and often had other comorbid conditions when compared with those without. Mortality was higher in patients with cardiac disease (29.7%; n = 1545 vs. 15.9%; n = 1797). However, following multivariable adjustment, this difference was not significant [adjusted risk ratio (aRR) 1.08, 95% confidence interval (CI) 1.02–1.15; P = 0.12 (corrected for multiple testing)]. Associations with in-hospital mortality by heart disease subtypes differed considerably, with the strongest association for heart failure (aRR 1.19, 95% CI 1.10–1.30; P < 0.018) particularly for severe (New York Heart Association class III/IV) heart failure (aRR 1.41, 95% CI 1.20–1.64; P < 0.018). None of the other heart disease subtypes, including ischaemic heart disease, remained significant after multivariable adjustment. Serious cardiac complications were diagnosed in <1% of patients. Conclusion Considerable heterogeneity exists in the strength of association between heart disease subtypes and in-hospital mortality. Of all patients with heart disease, those with heart failure are at greatest risk of death when hospitalized with COVID-19. Serious cardiac complications are rare during hospitalization.

Summary Purpose:  Cases of severe childhood epilepsies in temporal association with vaccination have great impact on the acceptance of vaccination programs by parents and health care providers. However, little is known about the type and frequency of seizures and epilepsy syndromes following vaccination. This study aims to describe the clinical features of children presenting with seizures after vaccination using a register‐based cohort. Methods:  We surveyed the national German database of adverse events following immunization (AEFI) for reported seizures and epilepsies in children aged 0–6 years. All cases reported in 2006–2008 were analyzed retrospectively; available clinical information was reevaluated and classified by seizure type and epilepsy syndrome. Key Findings:  In total, 328 cases reported between 2006 and 2008 were included. Data supportive of seizures or epilepsy were present in 247 (75.3%) of 328 patients with a mean interval between the vaccination and the epileptic event of 24 h and 7.5 days for inactivated and attenuated vaccines, respectively. Fifty‐one (15.5%) of 328 patients presented with syncope, hypotonic–hyporesponsive episodes, or other nonepileptic events. Information was insufficient for classification into epileptic versus nonepileptic events in 30 (11.3%) of 328 patients. For cases with confirmed seizures, febrile seizures were present in 121 (49%) of 247 cases, and 38 (15.4%) of 247 patients had single afebrile seizures. Status epilepticus was described in 21 (8.5%) of 247 patients. Thirty‐one (12.6%) of 247 patients presented with various pediatric epilepsy syndromes. Severe childhood epilepsies (Dravet syndrome, West syndrome, Lennox–Gastaut syndrome, or Doose syndrome) were diagnosed in 29 (11.7%) of 247 patients, with the vaccination‐associated event being the first documented seizure in 15 (51.7%) of 29 patients. Significance:  Vaccination‐associated seizures present in the setting of various epilepsy syndromes, including severe childhood epilepsies in >10% of cases. Early diagnosis of the corresponding epilepsy syndromes and confirmation of an underlying etiology is important for treatment decisions, genetic counseling, and public health evaluation of vaccine safety.