Grade 3: symptomatic due to drop in ejection fraction responsive to intervention 

Grade 4: refractory or poorly controlled heart failure due to drop in ejection fraction; intervention such as ventricular assist device, intravenous vasopressor support, or heart transplant indicated 

Grade 5: death

Adapted from Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0 Published: November 27, 2017