Publications

Cardiac magnetic resonance (CMR) imaging has been established as a valuable diagnostic tool in the assessment of pericardial diseases by providing information on cardiac anatomy and function, surrounding extra-cardiac structures, pericardial thickening and effusion, characterization of pericardial effusion, and the presence of active pericardial inflammation from the same scan. In addition, CMR imaging has excellent diagnostic accuracy for the non-invasive detection of constrictive physiology evading the need for invasive catheterization in most instances. Growing evidence in the field suggests that pericardial enhancement on CMR is not only diagnostic of pericarditis but also has prognostic value for pericarditis recurrence, although such evidence is derived from small patient cohorts. CMR findings could also be used to guide treatment de-escalation or up-titration in recurrent pericarditis and selecting patients most likely to benefit from novel treatments such as anakinra and rilonacept. This article is an overview of the CMR applications in pericardial syndromes as a primer for reporting physicians. We sought to provide a summary of the clinical protocols used and an interpretation of the major CMR findings in the setting of pericardial diseases. We also discuss points that are less well clear and delineate the strengths and weak points of CMR in pericardial diseases.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) or arrhythmogenic cardiomyopathy is a rare inherited disease with incomplete penetrance and an environmental component. Although a rare disease, ARVC is a common cause of sudden cardiac death in young adults. Data on the different stages of ARVC remains scarce. The purpose of this study is to describe the initial presentation and cardiac phenotype of definite and non-definite ARVC for patients seen at a tertiary service.

Existing microbiome-based disease prediction relies on the ability of machine learning methods to differentiate disease from healthy subjects based on the observed taxa abundance across samples. Despite numerous microbes have been implicated as potential biomarkers, challenges remain due to not only the statistical nature of microbiome data but also the lack of understanding of microbial interactions which can be indicative of the disease.

Coagulation factor (F) Xa induces proinflammatory responses through activation of protease-activated receptors (PARs). However, the effect of FXa on cardiac fibroblasts (CFs) and the contribution of PARs in FXa-induced cellular signalling in CF has not been fully characterised. To answer these questions, human and rat CFs were incubated with FXa (or TRAP-14, PAR-1 agonist). Gene expression of pro-fibrotic and proinflammatory markers was determined by qRT-PCR after 4 and 24 h. Gene silencing of (PAR-1) and (PAR-2) was achieved using siRNA. MCP-1 protein levels were measured by ELISA of FXa-conditioned media at 24 h. Cell proliferation was assessed after 24 h of incubation with FXa ± SCH79797 (PAR-1 antagonist). In rat CFs, FXa induced upregulation of (MCP-1; >30-fold at 4 h in atrial and ventricular CF) and (IL-6; ±7-fold at 4 h in ventricular CF). Increased MCP-1 protein levels were detected in FXa-conditioned media at 24 h. In human CF, FXa upregulated the gene expression of (>3-fold) and (>4-fold) at 4 h. Silencing of (PAR-1 gene), but not (PAR-2 gene), downregulated this effect. Selective activation of PAR-1 by TRAP-14 increased and gene expression; this was prevented by (PAR-1 gene) knockdown. Moreover, SCH79797 decreased FXa-induced proliferation after 24 h. In conclusion, our study shows that FXa induces overexpression of proinflammatory genes in human CFs via PAR-1, which was found to be the most abundant PARs isoform in this cell type.

Both inherited and acquired cardiac arrhythmias are often associated with the abnormal functional expression of ion channels at the cellular level. The complex machinery that continuously traffics, anchors, organizes, and recycles ion channels at the plasma membrane of a cardiomyocyte appears to be a major source of channel dysfunction during cardiac arrhythmias. This has been well established with the discovery of mutations in the genes encoding several ion channels and ion channel partners during inherited cardiac arrhythmias. Fibrosis, altered myocyte contacts, and post-transcriptional protein changes are common factors that disorganize normal channel trafficking during acquired cardiac arrhythmias. Channel availability, described notably for hERG and K1.5 channels, could be another potent arrhythmogenic mechanism. From this molecular knowledge on cardiac arrhythmias will emerge novel antiarrhythmic strategies.