Cooper, Leslie T.

Introduction: Cardiac sarcoidosis (CS) results in HFrEF, but its natural history and response to GDMT remains uncertain. Methods: We queried a registry of 631 CS patients evaluated at our institution to identify those with LVEF < 35% on TTE within 30 d of diagnosis and a follow-up TTE 12-18 months later (external CS diagnoses were excluded). Demographics, LVEF, NT-proBNP, GDMT, immunosuppression, CIED, and outcomes (hyperkalemia, LVAD/transplant, CV hospitalization, death) were recorded. Results: Overall, 25/631 (4%) of CS patients had an LVEF <35% at initial presentation (36% female, 84% white; median age of 58 y; probable/not biopsy-proven CS in 52%). Mean baseline LVEF was 27% (σ=7%), NT-proBNP 1736 pg/mL (n=11), potassium 4.3 mEq/L (n=18), and median NYHA Class II (54%). Patients were on a mean 1.7 GDMT agents at CS diagnosis (Figure). Most were treated with immunosuppression (88%) for mean 0.75 y, usually prednisone (88%, mean 16 mg daily) and fewer with mycophenolate (32%, mean 1875 mg daily), methotrexate (28%, mean 18mg weekly), or TNF-α inhibitor (4%). 64% were on trimethoprim-sulfamethoxazole prophylaxis. At follow-up (median 317 d), 3 patients (12%) required LVAD and 1 (4%) required heart transplant. Mean LVEF improved to 37% (excluding LVAD/transplant, σ=11%, p=0.001). CIED prevalence increased from 48 to 81% (p=0.03). Overall GDMT did not change (mean 2.0 agents, p=0.2) and only beta-blocker dose changed (64 to 138 mg mean daily metoprolol equivalents). Potassium did not change (p=0.4) and hyperkalemic events were infrequent (16%). No patients died, but unplanned hospitalization occurred in 36% of patients. Conclusions: CS patients with HFrEF are usually on partial GDMT at diagnosis, presumably due to earlier recognition of HFrEF, but intensification of GDMT may be limited. Despite improved LVEF which may be due to GDMT, immunosuppression, and/or CIED, over 1/3 patients were hospitalized within 18 mo, highlighting the high-risk profile of HFrEF in CS.

BACKGROUND: Dilated cardiomyopathy (DCM) is a major cause of heart failure and carries a high mortality rate. Myocardial recovery in DCM-related heart failure patients is highly variable, with some patients having little or no response to standard drug therapy. A genome-wide association study may agnostically identify biomarkers and provide novel insight into the biology of myocardial recovery in DCM. METHODS: A genome-wide association study for change in left ventricular ejection fraction was performed in 686 White subjects with recent-onset DCM who received standard pharmacotherapy. Genome-wide association study signals were subsequently functionally validated and studied in relevant cellular models to understand molecular mechanisms that may have contributed to the change in left ventricular ejection fraction. RESULTS: The genome-wide association study identified a highly suggestive locus that mapped to the 5′-flanking region of the CDCP1 (CUB [complement C1r/C1s, Uegf, and Bmp1] domain containing protein 1) gene (rs6773435; P =7.12×10 −7 ). The variant allele was associated with improved cardiac function and decreased CDCP1 transcription. CDCP1 expression was significantly upregulated in human cardiac fibroblasts (HCFs) in response to the PDGF (platelet-derived growth factor) signaling, and knockdown of CDCP1 significantly repressed HCF proliferation and decreased AKT (protein kinase B) phosphorylation. Transcriptomic profiling after CDCP1 knockdown in HCFs supported the conclusion that CDCP1 regulates HCF proliferation and mitosis. In addition, CDCP1 knockdown in HCFs resulted in significantly decreased expression of soluble ST2 (suppression of tumorigenicity-2), a prognostic biomarker for heart failure and inductor of cardiac fibrosis. CONCLUSIONS: CDCP1 may play an important role in myocardial recovery in recent-onset DCM and mediates its effect primarily by attenuating cardiac fibrosis.

AbstractPatients with viral myocarditis are at risk of sudden death and may progress to dilated cardiomyopathy (DCM). Currently, no disease‐specific therapies exist to treat viral myocarditis. Here it is examined whether reconstituted, lyophilized extracellular vesicles (EVs) from platelets from healthy men and women reduce acute or chronic myocarditis in male mice. Human‐platelet‐derived EVs (PEV) do not cause toxicity, damage, or inflammation in naïve mice. PEV administered during the innate immune response significantly reduces myocarditis with fewer epidermal growth factor (EGF)‐like module‐containing mucin‐like hormone receptor‐like 1 (F4/80) macrophages, T cells (cluster of differentiation molecules 4 and 8, CD4 and CD8), and mast cells, and improved cardiac function. Innate immune mediators known to increase myocarditis are decreased by innate PEV treatment including Toll‐like receptor (TLR)4 and complement. PEV also significantly reduces perivascular fibrosis and remodeling including interleukin 1 beta (IL‐1β), transforming growth factor‐beta 1, matrix metalloproteinase, collagen genes, and mast cell degranulation. PEV given at days 7–9 after infection reduces myocarditis and improves cardiac function. MicroRNA (miR) sequencing reveals that PEV contains miRs that decrease viral replication, TLR4 signaling, and T‐cell activation. These data show that EVs from the platelets of healthy individuals can significantly reduce myocarditis and improve cardiac function.

Myocarditis is most recognized in patients with moderate to severe, recent‐onset heart failure. However, less typical presentations including myocardial infarction with normal coronary arteries and arrhythmias are important manifestations but less commonly recognized to be caused by myocarditis. Most cases of myocarditis can be self‐limiting without specific treatment; however, appropriate identification of risk during the diagnostic process of myocarditis and once a diagnosis is established is of primordial importance to identify patients in need for more specific follow‐up and management. We propose a flexible, multitiered approach to the diagnostic process, allowing for capturing of the spectrum of myocarditis at an early time‐point, individualized use of diagnostic resources through disease severity phenotyping, and providing structured follow‐up care once myocarditis is confirmed. Such diagnostic processes allow for identification of specific etiologies with potential therapeutic consequences or allows for the comprehension of disease chronicity by understanding genetic contributions or elements of persistent immune dysregulation and degree of cardiac damage. The article highlights the evolving field of immunophenotyping in myocarditis, generating a potential for the development of targeted therapeutic approaches. Currently long‐term follow‐up should be titrated to the refined risk assessments of patients with a diagnosis of myocarditis and includes arrhythmia monitoring and imaging when the results will likely impact management. Genetic testing should be considered in selected cases, and histologic diagnosis may be considered in nonresponders even at later stages.

Introduction: Myocardial inflammation likely contributes to the pathogenesis of arrhythmogenic cardiomyopathy (ACM), a clinically and genetically heterogenous disorder characterized by ventricular dysfunction and potentially life-threatening ventricular arrhythmias. Due to phenotypic overlap, some patients with genetic ACM may have been evaluated for an underlying inflammatory cardiomyopathy, namely cardiac sarcoidosis. However, the cardiac fludeoxyglucose (FDG) positron emission tomography (PET) findings in ACM patients have not been assessed systematically. Methods: All genotype-positive patients in the Mayo Clinic ACM registry who received a cardiac FDG PET were included in this study. The cardiac FDG PET scan consisted of a resting myocardial perfusion scan with N13-ammonia as well as a F18-FDG scan after a high-fat diet to suppress physiologic FDG uptake. Pertinent demographic, genetic, imaging, and outcome data were extracted from the medical record. Results: Collectively, 12 (75% female) genotype-positive ACM patients received a cardiac PET FDG scan as part of their clinical evaluation (median age at scan 45.3 years [IQR 38.9-62.1]). Amongst these patients, pathogenic/likely pathogenic variants were detected in LMNA (n=7), DSP (n=3), FLNC (n=1), and PLN (n=1). Of note, 6/12 (50%) had abnormal myocardial FDG uptake, including diffuse (entire myocardium) uptake in 2/6 (33%), focal (1-2 segments) uptake in 2/6 (33%) and patchy (3+ segments) in 2/6 (33%). Median myocardial standardized uptake value ratio was 2.1 (IQR 1.5-2.6). Interestingly, LMNA -positive patients accounted for 3 out of 6 (50%) positive studies (diffuse uptake in 2 and focal uptake in 1). Conclusion: Myocardial FDG uptake is common in genetic ACM patients undergoing cardiac FDG PET. This finding further supports the role of myocardial inflammation in genetic ACM and demonstrates the ability of cardiac FDG PET to readily detect this phenomenon. Further investigation is needed to determine (i) the role of cardiac FDG PET in the evaluation of genetic ACM, (ii) if FDG uptake in genetic ACM has prognostic value and (iii) whether the attenuation of myocardial inflammation with immunosuppressive agents can impact the clinical course of inflammatory genetic ACMs.

Introduction: Cardiac sarcoidosis (CS) is a non-ischemic disease which can present with right ventricular (RV) dysfunction, but there is a paucity of research describing RV function and natural history in CS. Methods: We queried a registry of 512 CS patients for those with baseline and follow-up echocardiography (TTE). Demographics, medications, and baseline/follow-up TTE data were collected. RV-pulmonary arterial (RV-PA) coupling was approximated by ratio of tricuspid annular plane systolic excursion to estimated pulmonary artery systolic pressure (TAPSE:ePASP). Results: Our query yielded 343 CS patients with mean age 56y (σ=12y), who were predominantly male (67%) and white (90%) with a median follow-up 4y (interquartile range 4.1y). Most had pulmonary sarcoidosis (68%). Baseline TTE data showed left ventricular ejection fraction 48% (σ=14), abnormal RV function with RV systolic pressure (ePASP) 34 mmHg (σ=11), TAPSE 21mm (σ=5), RV S′ 0.14 m/s (σ=0.07), and RV-PA uncoupling (TAPSE:ePASP 0.69 mm/mm Hg, σ=0.25). Baseline RV function parameters did not differ by pulmonary involvement of sarcoidosis. 92% received immunosuppression and 65% received neurohormonal blockade. In long-term follow-up, the overall cohort demonstrated a trend towards worsening of both RV S’ and RV-PA coupling (P=.02 and P=.003 for linear trend, respectively) but stable ePASP (P=.11). Trends in both non-invasive ePASP and RV-PA coupling were similar in patients with and without pulmonary involvement (P=.48 and P=.79, respectively). Conclusions: In our large CS cohort with extensive follow-up, metrics of RV function and RV-PA coupling are often abnormal at CS diagnosis. Echocardiographic measures of PASP tend to remain stable but markers of RV dysfunction, including RV-PA coupling, tend to worsen throughout the disease course irrespective of pulmonary sarcoidosis. More granular phenotyping of pulmonary hypertension in CS is required to better understand this relationship.

e14674 Background: Myocarditis is an uncommon but serious adverse event (AE) of immune checkpoint inhibitor (ICI) therapy. We aimed to identify factors associated with ICI-related myocarditis in cancer patients using pooled data from multiple clinical trials. Methods: Data on 25,965 adults receiving at least one dose of an ICI (nivolumab [NIVO] or ipilimumab [IPI])-containing regimen were extracted from corporate safety and clinical trial databases. Patients missing documentation of AEs, indication, or trial ID were excluded. Myocarditis events were identified using MedDRA preferred terms. A nested case-control study design with controls who had no myocarditis selected at random from the risk sets and matched 1:5 on ICI regimen, duration of exposure to ICI regimen, and trial ID was used. Descriptive statistics were used to derive time to onset of myocarditis and to investigate patterns of myositis and rhabdomyolysis relative to myocarditis. A multivariable conditional logistic regression model was used to identify factors associated with myocarditis. Covariates included age, sex, race/ethnicity, medical history (cardiovascular disease, diabetes, sleep apnea), smoking, cancer type, medication use (within the prior 6 months), and co-occurrences of other AEs (pneumonitis, colitis, and hepatitis). Results: Myocarditis was documented in 122/24,106 (0.5%) patients meeting study eligibility criteria. A total of 732 patients (122 cases and 610 matched controls) from 46 trials were included in the analyses. Mean (SD) age was 63 (12) years; 65% of patients were male, 76% Caucasian, and 52% had a history of cardiovascular disease. NIVO + IPI was the most commonly used regimen (36%), followed by NIVO + relatlimab (25%) and NIVO + chemotherapy (14%). Median (Q1-Q3) time to onset of myocarditis was 38 (26-77) days from first dose of ICI. Myositis was reported in 18/122 (15%) cases and in 2/610 (0.3%) controls (p<0.001). Among the 18 cases, a majority (83%) developed myositis within 3 days before the onset of myocarditis. Rhabdomyolysis was reported in 4/122 (3%) cases, all within a month before myocarditis, and in none of the controls (p=0.001). In adjusted analyses, older age (odds ratio 1.38 per 10-year increase, 95% CI 1.12-1.70) and hepatitis (5.69, 2.24-14.44) were significantly associated with the development of myocarditis. Conclusions: In this large cohort of ICI-treated cancer patients, myocarditis had an early onset and was associated with older age and co-occurrences of hepatitis. Due to a low incidence among controls, rhabdomyolysis and myositis could not be included as covariates in adjusted analyses; however bivariate results showed strong associations between myocarditis and rhabdomyolysis or myositis. These findings suggest that co-occurrences of myositis, rhabdomyolysis, or hepatitis are associated with myocarditis and may originate from a more generalized ICI myopathy.

Viral infections are a leading cause of myocarditis and pericarditis worldwide, conditions that frequently coexist. Myocarditis and pericarditis were some of the early comorbidities associated with SARS-CoV-2 infection and COVID-19. Many epidemiologic studies have been conducted since that time concluding that SARS-CoV-2 increased the incidence of myocarditis/pericarditis at least 15× over pre-COVID levels although the condition remains rare. The incidence of myocarditis pre-COVID was reported at 1 to 10 cases/100 000 individuals and with COVID ranging from 150 to 4000 cases/100 000 individuals. Before COVID-19, some vaccines were reported to cause myocarditis and pericarditis in rare cases, but the use of novel mRNA platforms led to a higher number of reported cases than with previous platforms providing new insight into potential pathogenic mechanisms. The incidence of COVID-19 vaccine-associated myocarditis/pericarditis covers a large range depending on the vaccine platform, age, and sex examined. Importantly, the findings highlight that myocarditis occurs predominantly in male patients aged 12 to 40 years regardless of whether the cause was due to a virus-like SARS-CoV-2 or associated with a vaccine—a demographic that has been reported before COVID-19. This review discusses findings from COVID-19 and COVID-19 vaccine-associated myocarditis and pericarditis considering the known symptoms, diagnosis, management, treatment, and pathogenesis of disease that has been gleaned from clinical research and animal models. Sex differences in the immune response to COVID-19 are discussed, and theories for how mRNA vaccines could lead to myocarditis/pericarditis are proposed. Additionally, gaps in our understanding that need further research are raised.

Over recent years, preclinical and clinical evidence has implicated myocardial inflammation (M-Infl) in the pathophysiology and phenotypes of traditionally genetic cardiomyopathies. M-Infl resembling myocarditis on imaging and histology occurs frequently as a clinical manifestation of classically genetic cardiac diseases, including dilated and arrhythmogenic cardiomyopathy. The emerging role of M-Infl in disease pathophysiology is leading to the identification of druggable targets for molecular treatment of the inflammatory process and a new paradigm in the field of cardiomyopathies. Cardiomyopathies constitute a leading cause of heart failure and arrhythmic sudden death in the young population. The aim of this review is to present, from bedside to bench, the current state of the art about the genetic basis of M-Infl in nonischemic cardiomyopathies of the dilated and arrhythmogenic spectrum in order to prompt future research towards the identification of novel mechanisms and treatment targets, with the ultimate goal of lowering disease morbidity and mortality.