APR Cardiovascular System Practice Test

BNP is a hormone released by the ventricles in response to increased wall stress from volume or pressure overload. In heart failure, the heart struggles to handle the volume, so filling pressures rise and BNP levels go up, reflecting how severe the failure is. Because effective therapy reduces congestion and wall tension, BNP levels often fall as a patient improves. This makes BNP a useful tool for both gauging severity and tracking response to treatment; a higher level signals worse status, and a downward trend indicates improvement.

BNP isn’t a diagnostic test for myocardial infarction—diagnosis relies on clinical presentation, ECG changes, and cardiac troponins. It also doesn’t directly measure ejection fraction, which is an imaging estimate of pumping function. Lastly, BNP levels can change with therapy, so they are not unaffected by treatment.