HF Pathophysiology
Heart failure = inability of the heart to pump sufficient blood to meet the body's metabolic demands. Primary injury (MI, cardiomyopathy, HTN, valvular disease) → decreased CO → neurohormonal activation (RAAS, SNS, ADH release) → vasoconstriction + fluid retention → increased preload + afterload → worsening cardiac remodeling. BNP (B-type natriuretic peptide) released by ventricular myocardium in response to stretch — key diagnostic biomarker.
Types of Heart Failure
HFrEF (Heart Failure with Reduced Ejection Fraction): EF <40%; systolic dysfunction — heart cannot contract adequately. HFpEF (preserved EF): EF ≥50%; diastolic dysfunction — heart cannot relax and fill adequately; increasingly common, especially in elderly and hypertensive women. Right HF: systemic congestion (JVD, ascites, peripheral edema, hepatomegaly). Left HF: pulmonary congestion (crackles, dyspnea, orthopnea, PND).
Compensatory Mechanisms
Short-term (initially helpful, long-term harmful): (1) Frank-Starling: increased preload → increased SV (limited). (2) Sympathetic activation: tachycardia + vasoconstriction. (3) Ventricular hypertrophy: thickened walls handle pressure better initially. (4) RAAS activation: sodium and water retention (fluid overload). (5) Ventricular remodeling: chamber dilation → further EF reduction. These mechanisms ultimately accelerate disease progression.
Clinical Manifestations
Left HF: dyspnea on exertion, orthopnea (use 2+ pillows), PND (waking at night breathless), crackles, S3 gallop, tachycardia, displaced PMI, fatigue. Right HF: JVD, peripheral pitting edema (ankles, sacrum in bedbound), ascites, hepatojugular reflux, anorexia/nausea (hepatic congestion), weight gain. NYHA Classification: I (no symptoms) → IV (symptoms at rest).
Nursing Management
Monitor: daily weights (same time, same scale, same clothing), I&O, edema, lung sounds, JVD, BNP, BMP. Medications: ACE-I/ARBs, beta-blockers, diuretics (furosemide), aldosterone antagonists (spironolactone), digoxin, SGLT2 inhibitors (empagliflozin) for HFrEF. Activity: balance rest and activity; cardiac rehab. Diet: sodium restriction (<2 g/day), fluid restriction as ordered. Position: HOB 30–45°. Patient teaching: daily weights, symptoms to report (3-lb gain in 2 days).
Important Notes
- Teach patients: weight gain of 2–3 lbs in 1 day or 5 lbs in 1 week = notify healthcare provider immediately.
- Spironolactone causes hyperkalemia — monitor K+ closely, especially with ACE-I or ARBs.
Clinical Tips
- S3 gallop = hallmark of HFrEF — "lub-dub-da" best heard at apex with bell of stethoscope.
- BNP >100 pg/mL is consistent with HF; >400 pg/mL strongly suggests HF exacerbation.
Summary
Heart failure is a progressive syndrome driven by neurohormonal activation and cardiac remodeling. Evidence-based nursing management includes medications, monitoring, diet, activity, and comprehensive patient education to prevent readmission.
