Monitoring therapy of AMI

Decrease in troponin after treatment -> treatment successful
High troponin -> Worse prognosis
Immediately following reperfusion, troponin may temporarily increase

Heart failure

Heart failure is a clinical syndrome where the patient has symptoms and/or signs of insufficient cardiac output and/or backwards congestion. This is due to an underlying decrease in systolic or diastolic function of the heart.

Natriuretic peptides

The most important biomarkers for heart failure are the natriuretic peptides, NT-proBNP and BNP. Of these, NT-proBNP is the most used. These biomarkers have high negative predictive value, so NT-proBNP in a normal range makes HF very unlikely. They also have prognostic value and value in monitoring progression.

The level of NT-proBNP correlates with the severity of the HF, and a high value is associated with a worse prognosis. However, while it’s a sensitive biomarker, it’s not a specific one. NT-proBNP can be elevated in other conditions, like renal failure, pulmonary embolism, etc. NT-proBNP can be false negative in HFpEF.

Brain natriuretic peptide (BNP) is a hormone produced in the ventricles (initially discovered in the brain, hence the name). It increases natriuresis (sodium excretion in the kidneys) in response to pressure and volume overload in the ventricles, which occurs in heart failure.

Electrolytes

Hyponatraemia is a common feature in heart failure, due to reduction in circulating blood volume from oedema. This increases ADH secretion, giving hyponatraemia. Hyponatraemia also increases due to natriuretic peptide secretion.