B-Type Natriuretic Peptide

Key points

• Hormone produced mainly by the left ventricular myocardium in response to strain
• Effects: vasodilator · diuretic and natriuretic · suppresses both sympathetic tone and the renin-angiotensin-aldosterone system
• Raised by any cause of LV dysfunction (myocardial ischaemia, valvular disease) and by reduced excretion in chronic kidney disease · lowered by ACE inhibitors, angiotensin-2 receptor blockers and diuretics
• Acute dyspnoea: BNP < 100 pg/ml makes heart failure unlikely, but raised levels should prompt further investigation — NICE recommends BNP as a helpful test to rule out heart failure
• Also: extremely useful prognostic marker in chronic heart failure · effective treatment lowers BNP · not currently recommended for population screening

Decision points in this pathway

• Acute dyspnoea — is BNP < 100 pg/ml?

The full step-by-step algorithm, including what to do at each branch, opens in the app for approved members.