Graphical Abstract.

Proposed eight-point-based management of patients with a suspicion for a cardiovascular immune-related adverse event. ^aTroponin testing may be positive if Troponin I or T is >99th percentile of the upper reference limit. Concomitant myositis may result in significant elevations of CK, CK isoforms, and even Troponin T. In patients with pre-therapeutic troponin elevation, a 50% increase of the level may be used as a cut-off, but no evidence currently supports this recommendation. ^bHaemodynamic instability, heart failure requiring non-invasive or invasive ventilation, complete or high-grade heart block, and/or significant ventricular arrhythmia. ^cArrhythmias, conduction abnormalities, acute coronary syndromes, stroke, thromboembolic events, and heart failure should be managed urgently according to the international guidelines. ^dEndomyocardial biopsy should be performed especially in unstable patients who cannot undergo urgent CMR and in patients with uncertain diagnosis. ^eSee Table 2. ^fDefined as hemodynamic instability or electrical instability or increasing troponin or decreasing left ventricular ejection fraction. ^gThere are no data to recommend a standardized initial treatment strategy for the intensification of immunosuppressive therapy. For now, case series and case reports have shown the potential efficacy of anti-thymocyte globulin, intravenous immunoglobulin, plasma exchange, mycophenolate mofetil, tacrolimus, tocilizumab, abatacept, alemtuzumab, and tofacitinib. The decision regarding optimal therapy must be multidisciplinary, involving specialists in immunology and organ rejection. Infliximab was also proposed but was not incorporated into the algorithm because of its contraindication in acute heart failure. ⁱTroponin elevation without cardiovascular signs/symptoms and negative investigations including EMB. ACS, acute coronary syndrome; CCU, coronary care unit; CK, creatine kinase; AchR, acetylcholine receptor antibodies; CMR, cardiac magnetic resonance; EMB, endomyocardial biopsy; irAE, immune-related adverse event; ICI, immune checkpoint inhibitor; NT-proBNP, N-terminal-pro-brain-natriuretic-peptide; SMB, skeletal muscle biopsy; TSH, thyroid-stimulating hormone; TTE, transthoracic echocardiography; TTS, takotsubo syndrome.