Final answer:
Heart failure mortality is more closely related to the American Heart Association classes than ejection fraction, reflecting the importance of symptom severity in predicting outcomes.
Step-by-step explanation:
Mortality associated with heart failure is more closely tied to the classes established by the American Heart Association than to ejection fraction. Classes developed by the American Heart Association categorize the severity of heart failure based on symptoms and physical limitations, which correlate more closely with outcomes and mortality rates than simply ejection fraction, a measure of how well the heart pumps with each beat. Ejection fraction is an important clinical measure, but it alone does not fully capture the risk and progression of heart failure in patients.