Heart Failure Notes

Heart Failure: Study Notes

Definition

• Clinical syndrome where the heart cannot meet the perfusion demands of the body.

• Two main mechanisms:

  • Systolic dysfunction → impaired pumping → Heart Failure with Reduced Ejection Fraction (HFrEF).

  • Diastolic dysfunction → impaired filling → Heart Failure with Preserved Ejection Fraction (HFpEF).

• Newer category: Heart Failure with Mildly Reduced EF (HFmrEF) → EF 40–49%.

Key Hemodynamics & Definitions

• Cardiac Output (CO) = Stroke Volume (SV) × Heart Rate (HR).

  • SV ≈ 70 mL, HR ≈ 70 bpm → CO ≈ 5 L/min.

• Systole: ventricular contraction (blood ejection).

• Diastole: ventricular relaxation/filling.

• Ejection Fraction (EF) = SV ÷ End-Diastolic Volume (EDV).

  • Normal EF: 55–70%.

  • HFrEF: EF <40%.

  • HFpEF: EF ≥50%.

  • HFmrEF: EF 40–49%.

Classifications

• By side: left-sided, right-sided, or biventricular.

• By onset: acute or chronic.

Etiology

• HFrEF:

  • Coronary artery disease (MI).

  • Chronic volume overload → valvular disease (mitral/aortic regurgitation).

  • Dilated cardiomyopathy.

  • Neurohormonal changes (RAAS activation).

  • Increased afterload (HTN, severe aortic stenosis).

• HFpEF:

  • Stiff LV (LV hypertrophy, restrictive cardiomyopathy, fibrosis, pericardial constriction).

  • More common in elderly, women, and patients with high comorbidity burden.

• Common risk factors: obesity, hypertension, diabetes, renal disease.

Pathophysiology

• Left-sided HF → blood backs up into lungs → pulmonary edema, dyspnea.

• Right-sided HF → blood backs up into systemic veins → JVP elevation, hepatomegaly, peripheral edema.

• Most common cause of right-sided HF: left-sided HF.

Clinical Features

• Symptoms:

  • Dyspnea, orthopnea, paroxysmal nocturnal dyspnea.

  • Fatigue, exercise intolerance.

• Signs:

  • Pulmonary crackles, raised JVP, hepatomegaly, peripheral edema.

  • Heart sounds: S3 (dilated ventricle), S4 (stiff ventricle).

  • Hepatojugular reflux.

Diagnostics

• Labs:

  • NT-proBNP ↑ (marker of volume/pressure overload).

  • High levels (>5000 pg/mL) → poor prognosis.

• Imaging:

  • Chest X-ray: pulmonary edema, pleural effusion, cardiomegaly.

  • Echocardiography: EF, chamber size, valve function.

• Scoring systems: Framingham, Boston criteria.

Management

Goals

1. Improve survival (mortality reduction).

2. Control symptoms.

3. Slow disease progression.

HFrEF

• Mortality-reducing drugs:

  • ARNI (Sacubitril–Valsartan).

  • SGLT2 inhibitors (dapagliflozin, empagliflozin).

  • Beta-blockers.

  • ACE inhibitors / ARBs (if ARNI not tolerated).

  • Mineralocorticoid receptor antagonists (Spironolactone).

• Symptom control:

  • Diuretics (loop diuretics for volume overload).

  • Digoxin (improves symptoms, not mortality).

HFpEF

• No proven mortality-reducing therapy.

• Focus: symptom relief, comorbidity management (HTN, AFib, diabetes, COPD).

Non-pharmacologic & Advanced Therapies

• Salt and fluid restriction.

• Lifestyle modification.

• Cardiac resynchronization therapy (CRT).

• Implantable cardioverter defibrillators (ICDs).

• Revascularization or valve surgery if indicated.

Prognosis

• Mortality ≈ 50% within 5 years.

• Sudden cardiac death is a common cause.

Functional Staging

• NYHA (New York Heart Association) → functional limitation classification (I–IV).

• ACC/AHA staging → progression of disease (A–D).