====== Module 6 – Heart Failure ======

Heart failure is a clinical syndrome of impaired forward flow and maladaptive neurohormonal activation.

It is not primarily a pump failure problem — it is a neurohormonal disease.

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===== Hemodynamic Foundation =====

Core equation:

**CO = HR × SV**

Stroke Volume depends on:

• Preload  
• Afterload  
• Contractility  

In heart failure:

• ↓ Contractility (HFrEF)
• ↑ Afterload
• ↑ Preload
• ↑ Neurohormonal activation (RAAS + SNS)

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===== Classification =====

==== HFrEF (Reduced EF) ====

• EF ≤ 40%
• Systolic dysfunction
• Proven mortality-reducing therapies exist

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==== HFpEF (Preserved EF) ====

• EF ≥ 50%
• Diastolic dysfunction
• Limited mortality-reducing therapies

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==== HFmrEF ====

• EF 41–49%
• Treated similar to HFrEF

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===== The Neurohormonal Model =====

Compensatory systems become maladaptive:

1. Sympathetic activation  

2. RAAS activation  

3. Aldosterone excess  

4. Ventricular remodeling  

Modern therapy blocks these pathways.

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==== Remodeling Prevention ====

Chronic neurohormonal activation causes:

  * • LV dilation
  * • Fibrosis
  * • Progressive decline in EF

GDMT prevents remodeling.

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===== **HFrEF – Guideline Directed Medical Therapy (GDMT)** =====

==== The Four Pillars of HFrEF Therapy ====

All patients with HFrEF should receive:

  - 1. [[cardio:raas:arni|ARNI]] (preferred) OR [[cardio:raas:acei|ACE Inhibitor]] OR [[cardio:raas:arb|ARB]]
  - 2. [[cardio:beta_blockers:start|Evidence-Based Beta-Blocker]]
  - 3. [[cardio:hf:mra|Mineralocorticoid Receptor Antagonist]]
  - 4. [[endocrine:sglt2:start|SGLT2 Inhibitor]]

These therapies reduce mortality and hospitalization.

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==== RAAS Inhibition ====

Preferred:

• [[cardio:raas:arni|Sacubitril/Valsartan (ARNI)]]

Alternative:

• [[cardio:raas:acei|ACE Inhibitor]]
• [[cardio:raas:arb|ARB]]

Effects:

• ↓ Afterload
• ↓ Aldosterone
• ↓ Remodeling
• ↓ Mortality

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==== Evidence-Based Beta-Blockers ====

Only three reduce mortality:

• [[cardio:beta_blockers:carvedilol|Carvedilol]]

• [[cardio:beta_blockers:metoprolol|Metoprolol Succinate]]

• [[cardio:beta_blockers:bisoprolol|Bisoprolol]]

Effects:

• ↓ Sympathetic drive
• ↓ Remodeling
• ↓ Sudden cardiac death

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==== Mineralocorticoid Receptor Antagonists (MRAs) ====

• [[cardio:hf:spironolactone|Spironolactone]]

• [[cardio:hf:eplerenone|Eplerenone]]

Effects:

• ↓ Aldosterone-mediated fibrosis
• ↓ Remodeling
• ↓ Mortality

Monitor potassium closely.

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==== SGLT2 Inhibitors ====

• [[endocrine:sglt2:dapagliflozin|Dapagliflozin]]

• [[endocrine:sglt2:empagliflozin|Empagliflozin]]

Effects:

• ↓ HF hospitalization
• ↓ Mortality
• Benefit independent of diabetes status

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==== Secondary / Add-On Therapies ====

[[cardio:hf:hydralazine_isdn|Hydralazine + Isosorbide Dinitrate]]

• Particularly beneficial in Black patients

[[cardio:arrhythmias:ivabradine|Ivabradine]]

• If HR ≥70 on maximally tolerated beta-blocker

[[cardio:hf:vericiguat|Vericiguat]]

• Soluble guanylate cyclase stimulator

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==== Diuretics (Symptom Control) ====

Diuretics DO NOT reduce mortality.

Used for congestion relief:

  * • [[cardio:diuretics:furosemide|Furosemide]]
  * • [[cardio:diuretics:torsemide|Torsemide]]

Effect:

  * • ↓ Preload
  * • ↓ Pulmonary edema
  * • Symptom improvement only

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===== **HFpEF** =====

**No strong mortality-reducing therapies except**:

• [[endocrine:sglt2:start|SGLT2 Inhibitors]]

Management focuses on:

  * • Blood pressure control
  * • Diuretics for congestion
  * • Treating atrial fibrillation
  * • Managing ischemia

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===== **Acute Decompensated Heart Failure** =====

==== Pulmonary Edema ====

• [[cardio:diuretics:furosemide|IV Loop Diuretics]]

• [[cardio:angina:nitroglycerin|Nitroglycerin]]

• Oxygen

• Positive pressure ventilation if needed

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==== Cardiogenic Shock ====

• [[cardio:inotropes:dobutamine|Dobutamine]]

• [[cardio:inotropes:dopamine|Dopamine]]

Short-term hemodynamic support only.

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==== Clinical Pearls ====

  * ✔ Heart failure is a neurohormonal disease  
  * ✔ Diuretics improve symptoms, not survival  
  * ✔ Four pillars reduce mortality  
  * ✔ Only specific beta-blockers reduce mortality  
  * ✔ SGLT2 inhibitors benefit even non-diabetics  
  * ✔ Start low, titrate slowly  

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Related:

→ [[cardio:hypertension:start|Hypertension Module]]
→ [[cardio:arrhythmias:start|Dysrhythmias Module]]
→ [[cardio:intro:start|Return to Cardiovascular Modules]]