Baksi, John

Abstract Cardiac sarcoidosis (CS) is a form of inflammatory cardiomyopathy associated with significant clinical complications such as high-degree atrioventricular block, ventricular tachycardia, and heart failure as well as sudden cardiac death. It is therefore important to provide an expert consensus statement summarizing the role of different available diagnostic tools and emphasizing the importance of a multidisciplinary approach. By integrating clinical information and the results of diagnostic tests, an accurate, validated, and timely diagnosis can be made, while alternative diagnoses can be reasonably excluded. This clinical expert consensus statement reviews the evidence on the management of different CS manifestations and provides advice to practicing clinicians in the field on the role of immunosuppression and the treatment of cardiac complications based on limited published data and the experience of international CS experts. The monitoring and risk stratification of patients with CS is also covered, while controversies and future research needs are explored.

Background: Myocarditis may predispose to dilated cardiomyopathy (DCM) and sudden cardiac death (SCD). Familial data indicate a potential genetic susceptibility shared with arrhythmogenic cardiomyopathy (ACM). We present the first large-scale genotype-phenotype study of adults with acute myocarditis. Methods: A cohort comprising 336 consecutive patients with acute myocarditis was enrolled in London and Maastricht. All participants underwent targeted DNA sequencing for well-characterised cardiomyopathy-associated genes. The burden of rare protein altering variants (PAV) in ACM genes, DCM genes, and TTN specifically, were compared with local healthy controls sequenced on the same platform (n=1053). Case ascertainment was assessed against national hospital admission data. Results: We identified rare protein-altering variants in 23% of cases compared to 16% in controls (Δ+6.8%; p=0.021), with rare truncating variants (tv) in 6% of cases compared to <1% of controls ((Δ+5%; p=0.0097). In London (n=230; median left ventricular ejection fraction (LVEF) 63%), which was representative of national myocarditis admissions, 4.8% of cases carried rare tv, particularly within ACM genes (3% cases vs 0% controls; odds ratio 8.2; p=0.001). This was predominantly driven by desmoplakin (DSP)-tv in patients with normal LVEF. In Maastricht (n=106; median LVEF 30%), rare tv in DCM genes were enriched, particularly TTN-tv found in 7% (all with LVEF<50%) compared to 1% in controls (OR 3.6; p=0.0116). During a median follow-up of 1.9 years, all-cause mortality was greatest in those with a DCM variant (18% vs 4% with no variant; OR 5.0; p=0.004). Conclusion: We identified enrichment of cardiomyopathy gene variants in acute myocarditis patients, dominated by DSP-tv in those with normal LVEF and TTN-tv in those with reduced LVEF. Incorporation of genetic testing may be beneficial to identify such high-risk individuals and guide family screening in acute myocarditis patients.