Heart Failure Meds Study Notes

Heart Failure – Study Notes

Definition

• Systolic HF: heart unable to pump effectively → reduced ejection fraction.

• Diastolic HF: heart unable to fill properly → ejection fraction preserved.

• Both result in reduced cardiac output.

Pathophysiology

• ↓ Cardiac output → compensatory activation of:

  • RAAS → vasoconstriction, ↑ BP, ↑ HR, ventricular remodeling.

  • Sympathetic system → worsens cardiac workload.

• Aldosterone → ventricular scarring, vascular injury.

• Natriuretic peptides (protective) → vasodilation, natriuresis, ↓ remodeling.

Drug Therapy (Targets: inhibit RAAS/sympathetic, enhance natriuretic system, ↑ contractility, ↓ fluid retention)

1. ACE Inhibitors

   • Block angiotensin I → II.

   • Effects: ↓ RAAS activation.

   • SE: dry cough, headache, hypotension, rare angioedema.

2. ARBs

   • Block angiotensin II receptor.

   • Similar to ACEi, but no cough.

   • Less effective; used if ACEi not tolerated.

3. Beta-blockers

   • Block β1-receptors → ↓ HR, ↓ sympathetic effects.

   • SE: hypotension, bradycardia, AV block (rare).

4. Vasodilators

   • ↓ BP; alternative for ACEi/ARB intolerance.

   • SE: nausea, palpitations, rash, joint pain.

5. Diuretics

   • Relieve fluid retention.

   • Loop diuretics = most potent.

   • Thiazides = mild effect + vasodilation (good for HTN + mild fluid retention).

   • SE: electrolyte imbalance, hypovolemia, metabolic alkalosis.

6. Aldosterone Antagonists

   • Block aldosterone → K⁺-sparing diuretic + protective cardiac effect.

   • SE: hyperkalemia, renal impairment.

7. Digoxin

   • ↑ Contractility via Na⁺/K⁺ pump inhibition → ↑ intracellular Ca²⁺.

   • ↓ Sympathetic activity → slows HR.

   • Used if no response to first-line drugs.

   • SE: numerous, potentially toxic.

8. Ivabradine

   • Blocks “funny” channel (SA node) → ↓ HR.

   • SE: bradycardia, AFib, visual disturbances.

   • Avoid in: low HR, low BP, certain heart conditions.

9. ARNIs (Angiotensin receptor–neprilysin inhibitor)

   • Combo: neprilysin inhibitor + ARB.

   • Mechanism: ↑ natriuretic peptides, prevents RAAS activation.

   • SE: hypotension, hyperkalemia, renal failure.

   • Used when ACEi + beta-blockers inadequate.