Although cardiac involvement in immunological diseases is usually associated with a poor prognosis, it is often overlooked. Common manifestations are myocarditis, pericarditis, arrhythmias, vasculitis, or coronary heart disease. A general screening for cardiovascular involvement is not provided in the guidelines and does not seem sensible given the low frequency of most immunological diseases. However, in the case of the slightest cardiac symptoms, a thorough examination including the determination of troponin and NT-pro-BNP, electrocardiogram, echocardiography, and cardio-MRI should be carried out. Depending on availability and the underlying disease, a PET-CT or a combined PET-MRI and/or a myocardial biopsy should also be performed. The detection of cardiac involvement usually leads to an intensification of therapy, especially immunosuppression.