What happened, in summary

A 74-year-old man with a 50 pack-year smoking history had been diagnosed two years earlier with a poorly differentiated right upper lobe lung adenocarcinoma measuring about 50 mm and showing lymphovascular invasion. He underwent right lobectomy followed by cisplatin and vinorelbine, but severe nausea and vomiting limited adjuvant chemotherapy to three cycles.

Six months later, CT showed a recurrent right apical mass and a new left adrenal metastasis. Both sites were treated with stereotactic ablative radiation, and nivolumab was then started for metastatic disease. Three days after his second infusion, he developed increasing breathlessness, difficulty lying flat, lethargy, chest discomfort, and palpitations.

An electrocardiogram showed complete atrioventricular block. Cardiac testing supported nivolumab-related myocarditis with new left-ventricular dysfunction. Nivolumab was permanently discontinued. He received three days of high-dose intravenous methylprednisolone followed by oral prednisolone, and cardiac biomarkers gradually improved. Carvedilol and perindopril were added for heart dysfunction.

Despite biochemical improvement, the heart block persisted and caused episodes of slow heart rate and low blood pressure. A cardiac resynchronization pacemaker was implanted, after which carvedilol was restarted. He was discharged home in stable condition on maintenance steroids and heart-failure medication. He recovered sufficiently for discharge after treatment of the immune-related cardiac complication, while nivolumab remained permanently discontinued.