Natriuretic hormones, primarily atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), play a key role in managing cardiac failure by regulating blood pressure, fluid balance, and sodium excretion. Here’s how they relate to cardiac failure and blood pressure numbers (BPN):

• Atrial Natriuretic Peptide (ANP):
• Released by atrial myocytes in response to atrial stretch (e.g., from increased blood volume or pressure in heart failure).
• Effects: Promotes natriuresis (sodium excretion) and diuresis (water excretion) by the kidneys, reducing blood volume and lowering blood pressure. It also relaxes vascular smooth muscle, decreasing systemic vascular resistance, which can reduce BP (e.g., lowering systolic BP by 5-10 mmHg in some cases).
• In cardiac failure, ANP levels rise as a compensatory mechanism to counteract fluid overload and high BP, especially in acute heart failure or HFpEF where BP may be elevated (e.g., >140/90 mmHg).
• Brain Natriuretic Peptide (BNP):
• Secreted by ventricular myocytes in response to ventricular stretch and wall stress, which are common in both systolic (HFrEF) and diastolic (HFpEF) heart failure.
• Effects: Similar to ANP, BNP promotes natriuresis and diuresis, reducing preload and afterload, which lowers BP. It also inhibits the renin-angiotensin-aldosterone system (RAAS), further decreasing BP and fluid retention.
• In cardiac failure, elevated BNP levels are a hallmark, often correlating with disease severity. For example, BNP >400 pg/mL is diagnostic for heart failure. In HFrEF, where BP may be low (e.g., <100/60 mmHg), BNP helps mitigate fluid overload but may not fully normalize BP due to poor cardiac output.
• Impact on BPN in Cardiac Failure:
• In early or compensated heart failure, natriuretic hormones may help maintain BP within a normal range by reducing fluid overload and vascular resistance. For instance, in HFpEF, they counteract hypertension (e.g., reducing BP from 160/95 to 140/85 mmHg).
• In advanced HFrEF or cardiogenic shock, their effect is limited, and BP may remain low (e.g., <90/60 mmHg) due to failing pump function, despite high ANP/BNP levels.
• In acute decompensated heart failure, natriuretic hormones may lower dangerously high BP (e.g., >180/100 mmHg) by promoting diuresis, but medications like diuretics or vasodilators are often needed for rapid control.
• Clinical Relevance:
• BNP/NT-proBNP levels are used diagnostically and prognostically in heart failure. Higher levels often indicate worse outcomes and may correlate with lower BP in HFrEF due to severe cardiac dysfunction.
• Therapies like neprilysin inhibitors (e.g., sacubitril/valsartan) enhance natriuretic peptide activity, improving fluid balance and reducing BP, which is beneficial in HFrEF but requires careful monitoring to avoid hypotension.
• In patients with high BP in HFpEF, natriuretic hormones work alongside antihypertensives to manage pressure and prevent further cardiac strain.

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