Cardiac sarcoidosis (CS) is a complex disease that is characterized by the formation of inflammatory granulomas in the myocardium. The exact underlying pathophysiology of the disease is not yet fully understood, but it is believed to be related to dysregulation of the immune system. Despite significant progress in recent years, the disease remains difficult to diagnose, and there is a high risk of severe complications such as life-threatening cardiac arrhythmias, severe heart failure, and sudden cardiac death in affected patients.

Moreover, the clinical presentation of CS can be similar to other inflammatory heart diseases or familial cardiomyopathies. Thus, it is challenging to differentiate between these diseases, which can lead to a delayed diagnosis and poor prognosis. It is unclear whether certain genetic variants play a role in the clinical course and prognosis of CS, which highlights the need for more research in this area.

The diagnosis of CS requires cardiac or extracardiac biopsy with granuloma detection, which is an invasive and complex procedure. Consequently, the disease is thought to be underdiagnosed, and many affected patients may not receive timely treatment, resulting in excess mortality. Early diagnosis and immunosuppressive treatment, as well as defibrillator implantation if necessary, are crucial in delaying disease progression, preventing complications, and improving prognosis.

To better understand the key molecular pathological mechanisms underlying the development and maintenance of CS, a prospective, multicenter, exploratory study has been initiated. The project involves the collection, storage, and analysis of biological samples from blood, myocardium, and lymph nodes of patients with cardiac sarcoidosis or cardiomyopathies that present clinically and image morphologically similar. The samples will be used for scientific investigations on disease mechanisms of cardiomyopathies as well as for identification of new biomarkers in cardiomyopathy diagnostics and for follow-up of therapeutic measures.

The study will employ a range of classical biochemical methods such as ELISA, RIA, as well as more modern methods of molecular biology (single cell sequencing, single nucleus sequencing) and systems biology (genomics, metabolomics, or proteomics) to identify key molecular pathological mechanisms in the development and maintenance of CS.

In addition, genetic analysis will be performed to investigate cardiomyopathy- and ion channel-associated genetic variants, which is critical for improving diagnostics and early, individualized therapy. The study will be conducted on a multicenter basis, with the Heart Center Leipzig serving as the initiator and lead center and the University Hospital Leipzig as the second study center. Biochemical and molecular biological analyses will be performed on behalf of the study management at the Heart Center Leipzig, the University Hospital Leipzig, and the Erich and Hanna Klessmann Institute for Cardiovascular Research and Development of the Heart and Diabetes Center NRW and Max Delbrück Center for Molecular Medicine in Berlin.

In conclusion, CS is a complex and challenging disease that requires further research to better understand its underlying mechanisms and improve diagnostic and therapeutic strategies. The prospective, multicenter, exploratory study will provide valuable insights into the disease's key molecular pathological mechanisms and identify new biomarkers for better diagnostics and individualized therapy.

Inclusion Criteria:

(a) patients with a history of symptomatic cardiac sarcoidosis/inflammatory cardiomyopathy or b) patients with newly diagnosed heart failure with cardiac arrhythmias (ventricular tachycardia, conduction disturbances, etc.) that may indicate sarcoidosis or inflammatory cardiomyopathy or c) patients with image morphological suspicion of cardiac sarcoidosis or inflammatory cardiomyopathy (MRI, PET-CT) or (d) patients who require or have received a ventricular assist device (VAD) or cardiac transplantation due to suspected cardiac sarcoidosis or inflammatory cardiomyopathy and (e) written informed consent has been obtained from patients for study participation and consent for analysis of patient samples. Studies on pseudoanonymized samples will only be performed with appropriately signed informed consent.

Exclusion Criteria:

1. Patients with psychiatric illness that impairs business or insight capacity.
2. Patients with chronic heart failure due to coronary artery disease or valvular vitiation.
3. severe underlying disease other than sarcoidosis that is likely to result in death within one year.

tertiary care clinic patients with suspected inflammatory cardiomyopathy and/or conduction disorders and/or ventricular arrhythmias, suspected cardiac sarcoidosis.