Exercise intolerance - from spiroergometry to transdiaphragmatic myocardial punch biopsy: a case report of isolated cardiac sarcoidosis.

Differential diagnoses were either an infiltrative disease, a tumour, or an infectious disease. Due to the different treatment options, we had to establish definite diagnosis by myocardial biopsy. Retrospectively, the implantation of the ICD can be discussed. However, cardiac magnetic resonance imaging showed fibrosis which is usually irreversible and substrate for potentially lethal ventricular arrhythmia. Confirming the diagnosis of isolated CS is challenging. Long-term management should be guided individually based on clinical and imaging findings.