Outcome and Follow-up
She was diagnosed with osimertinib-induced acute heart failure due to TC. She was admitted to our institution on the same day for treatment of cardiac failure. Her condition improved after discontinuing osimertinib and adding treatment for heart failure.
Thirty-five days after admission, left ventricular wall motion abnormality improved to almost normal kinesis (Fig 1(C, D)), and electrocardiogram showed ST changes normalized after extensive negative T waves (Fig 2(C, D)). She improved from class IV to class II as per the New York Heart Association classification.
Since osimertinib was highly effective against lung cancer, the treatment was restarted at a reduced dose of 40 mg/day. After 63 days of restarted osimertinib therapy, an echocardiogram showed hypokinesis on the left ventricular apical portion (Fig 1(E, F)). Electrocardiogram showed reappearance of extensive negative T waves (Fig 2(E)). She was diagnosed with asymptomatic TC, and osimertinib treatment was subsequently stopped. Two weeks after stopping osimertinib, left ventricular wall motion improved to normal. She was started on 3rd-line chemotherapy.