Fulminant immune checkpoint inhibitor-associated myocarditis bridged to recovery with a temporary left ventricular assist device: a case report.

Background: Immune checkpoint inhibitors (ICIs) are effective antineoplastic agents but can cause adverse effects in many organ systems. Cardiovascular toxicities include arrhythmias, myocarditis, heart failure, takotsubo syndrome, pericarditis, coronary artery disease, and vasculitis.

Case Summary: A 66-year-old woman with Stage 3C2 endometrial carcinoma presented for her second cycle of pembrolizumab, carboplatin, and paclitaxel. She subsequently suffered cardiac arrest and was brought to the emergency department. Spontaneous circulation returned following resuscitation, but she was haemodynamically unstable. An electrocardiogram revealed complete heart block. Initial management included intubation, vasopressor support, and transcutaneous pacing before transfer to the catheterization lab. Coronary angiography revealed no coronary artery disease. Right heart catheterization confirmed severe cardiogenic shock despite inotropic support and a temporary transvenous pacemaker in place. A micro-axial flow pump (Impella CP) was implanted for deteriorating cardiogenic shock. She was treated with high-dose corticosteroids (dexamethasone 190 mg i.v.) for suspected ICI-associated myocarditis, with significant improvement in cardiac function. The Impella was weaned and removed on Day 5. Cardiac magnetic resonance imaging showed elevated T1 and T2 signal intensities, consistent with the 2018 Lake Louise Criteria for myocarditis. The complete heart block was resolved, but a leadless pacemaker was implanted due to pre-existing conduction abnormalities.

Discussion: Early recognition of ICI-associated myocarditis can be achieved with biochemical testing, electrocardiography, imaging, and expedited investigation of alternative causes for cardiac decompensation. Our case demonstrates that temporary left ventricular assist devices can support cardiac output for patients in cardiogenic shock due to ICI-associated myocarditis, allowing for recovery following high-dose corticosteroids.