Refractory Ventricular Arrhythmia in a Patient with Suspected Immune Checkpoint Inhibitor-Related Myocarditis: A Case Report and Literature Review

Background Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy by modulating immune responses, yet they can trigger rare, life-threatening complications such as myocarditis. Diagnosis remains challenging without confirmatory imaging or biopsy, particularly in hemodynamically unstable patients. Case Summary We report a 65-year-old male with esophageal cancer who developed refractory ventricular tachycardia three months after initiating toripalimab, a PD-1 inhibitor. Clinical suspicion of ICI-related myocarditis was based on ECG abnormalities (polymorphic ventricular tachycardia, ST-segment elevation), elevated troponin I (peak 7450 ng/L), and echocardiography showing reduced left ventricular ejection fraction (30%), with coronary angiography excluding significant obstructive disease. Due to hemodynamic instability, cardiac MRI or biopsy was not feasible. Treatment with high-dose methylprednisolone, immunoglobulin, and anti-arrhythmic drugs (amiodarone, esmolol) yielded limited success, with recurrent arrhythmias requiring multiple cardioversions. Following the family's thoughtful decision to forgo extracorporeal membrane oxygenation, the patient passed away shortly after discharge. Discussion This case underscores the diagnostic complexity of suspected ICI-related myocarditis and the critical need for early recognition of immune-mediated cardiac toxicity in immunotherapy patients, emphasizing the role of clinical vigilance when definitive diagnostics are unavailable.