Résumé
ICI are increasingly used in oncology, but can cause serious side-effects, including cardiac complications such as immuno-induced myocarditis, with a mortality rate of up to 50%. Diagnosis is based on clinical, biological and imaging criteria. Endomyocardial biopsy (EMB), considered the gold standard, has no established place. This observational study, carried out at Montpellier University Hospital between February 2022 and April 2024, included 39 patients with suspected myocarditis under immunotherapy, all of whom had undergone EMB. Patients were classified into 4 groups: definite, probable or possible myocarditis or troponin elevation unrelated to myocarditis. We then compared several subgroups according to symptomatology, rhythmic events and BEM results. EM was positive in 15% of cases according to Dallas criteria. Symptomatic patients more frequently had an altered ECG and were more likely to have definite myocarditis. Rhythm disorders were associated with more frequent impairment of left ventricular ejection fraction (LVEF <50%) and abnormal ECG, notably with negative T waves. Mortality was significantly higher in patients with rhythm disorders (38% vs. 0% p=0.008). here was no significant difference in terms of presentation (ECG, cardiac echocardiography and symptomatology) between the positive and negative BEM groups. The study highlights the difficulties involved in diagnosing immuno-induced myocarditis. Although BEM remains the gold-standard, its low positivity calls into question its usefulness. We need to develop more appropriate management strategies, integrating clinical and biological criteria to identify patients at risk.