Ischemic Cardiomyopathy (ICM) 

1. Definition

Ischemic cardiomyopathy (ICM) is a subtype of heart failure due to chronic myocardial ischemia or infarction leading to left ventricular systolic dysfunction (LVEF ≤40%), typically in the setting of coronary artery disease.

  • It is not just prior MI, but a remodeling disease driven by:
    • Repeated ischemia
    • Infarct scar formation
    • Hibernating myocardium

2. Epidemiology

  • Most common cause of heart failure worldwide
  • Responsible for:
    • ~60–70% of HFrEF cases in developed countries
  • High prevalence in:
    • Diabetes
    • Hypertension
    • Elderly males

3. Pathophysiology 

A. Initial Trigger

  • Atherosclerotic plaque → coronary stenosis → ↓ perfusion
  • Acute plaque rupture → MI → myocardial necrosis

B. Myocardial Consequences

1. Infarction → Scar Formation

  • Replacement fibrosis
  • Non-contractile myocardium
  • Regional wall motion abnormality

2. Hibernating Myocardium 

  • Chronically underperfused myocardium
  • Reduced function but viable
  • Improves after revascularization

3. Stunning

  • Transient LV dysfunction after ischemia despite reperfusion

C. Ventricular Remodeling

  • LV dilation
  • Spherical geometry
  • Increased wall stress (Laplace law)
  • Secondary MR

 Neurohormonal activation:

  • RAAS
  • SNS
  • ADH

→ Leads to progressive HF


4. Structural & Functional Changes

Feature

Description

LV size

Dilated

LV function

Reduced EF

Wall motion

Regional abnormalities

Mitral valve

Functional MR

Diastolic function

Impaired

Arrhythmia substrate

Fibrosis → reentry circuits

5. Clinical Features

A. Symptoms

  • Dyspnea (most common)
  • Orthopnea, PND
  • Fatigue
  • Angina (may be absent in advanced disease)

B. Signs

  • S3 gallop
  • Displaced apex
  • Pulmonary crepitations
  • Peripheral edema

C. Red Flags

  • Sudden cardiac death
  • Ventricular arrhythmias

6. Diagnosis

A. Confirm HF + Reduced EF

  • Echocardiography:
    • EF ≤40%
    • Regional wall motion abnormality → suggests ischemic cause


B. Demonstrate Ischemic Etiology

1. Coronary Imaging

  • Gold standard: Coronary angiography
  • CT coronary angiography in selected patients

2. Viability Assessment 

Modality

Finding

Dobutamine stress echo

Contractile reserve

Cardiac MRI

Late gadolinium enhancement

PET

Metabolic activity
  • Viable myocardium → benefit from revascularization

C. Differentiate from Non-Ischemic Cardiomyopathy

Feature

Ischemic

Non-Ischemic

Wall motion

Regional

Global

Coronary disease

Present

Absent

Scar pattern

Subendocardial/transmural

Mid-wall

7. Management (ESC 2023 / AHA 2022)

“Management of ischemic cardiomyopathy includes guideline-directed medical therapy for HFrEF PLUS revascularization and anti-ischemic therapy where indicated.”


A. Foundational Quadruple Therapy

  • ARNI (preferred) / ACEi / ARB
  • Beta-blocker (Carvedilol, Bisoprolol, Metoprolol succinate)
  • MRA (Spironolactone / Eplerenone)
  • SGLT2 inhibitors (Dapagliflozin / Empagliflozin)

B. Revascularization  Indications:

  • Significant CAD
  • Viable myocardium
  • Angina or large ischemic burden

Options:

  • PCI
  • CABG (preferred in multivessel disease)

 Evidence:STICH trial → CABG improves survival in ICM

 In non-ischemic cardiomyopathy → no role of revascularization

C. Anti-Ischemic Therapy

  • Antiplatelets (aspirin ± P2Y12 if indicated)
  • High-intensity statins
  • Nitrates (for angina)
  • Risk factor control (DM, HTN, smoking)

D. Viability-Guided Strategy

  • If myocardium is viable → revascularize
  • If scarred → focus on GDMT + devices

Target

How Achieved

HR 60–70(↓ myocardial oxygen demand, ↑ diastolic filling time, ↓ ischemia)

Beta-blockers, Ivabradine

BP 100–130(Maintain coronary perfusion but avoid ↑ afterload)

ACEi/ARNI, careful titration

↓ Preload

Diuretics, nitrates

↓ Afterload(Improves stroke volume and forward flow)

ACEi/ARB/ARNI, vasodilators

Optimize SVR(Excess SVR worsens LV dysfunction)

Avoid excessive vasoconstrictors

Improve contractility

GDMT ± inotropes (if shock)

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