Ischemic Dilated Cardiomyopathy

Definition and Pathophysiological Mechanisms

Ischemic dilated cardiomyopathy is a condition characterized by **left ventricular dilation and systolic dysfunction** secondary to chronic myocardial ischemia.
It is one of the most common causes of **heart failure with reduced ejection fraction (HFrEF)**. The primary pathophysiological mechanism is **ventricular remodeling** induced by repeated episodes of ischemia, myocardial necrosis, and fibrosis.

The main contributing factors are:

• Progressive cardiomyocyte loss: Repeated infarctions and chronic ischemia lead to apoptosis and cellular necrosis.
• Myocardial fibrosis: Replacement of functional myocardial tissue with scar tissue.
• Contractility alterations: Reduced ability to generate contractile force, leading to decreased cardiac output.
• Neurohormonal activation: Increased catecholamines, angiotensin II, and aldosterone levels, which promote myocardial damage progression.

Ischemic dilated cardiomyopathy is one of the leading causes of heart failure in patients with pre-existing **coronary artery disease**. The main risk factor is a **previous myocardial infarction**, which causes **irreversible myocardial necrosis and ventricular remodeling**. Additional risk factors include **hypertension, dyslipidemia, diabetes mellitus, and metabolic syndrome**.

Clinical Presentation and Diagnosis

The primary symptoms result from **left ventricular dysfunction and heart failure**.

Patients may experience:

• Dyspnea on exertion and orthopnea.
• Peripheral edema and venous congestion.
• Exercise intolerance and easy fatigue.
• Palpitations and ventricular arrhythmias.

Diagnostic tools include:

• ECG: Repolarization abnormalities, Q waves from previous infarction, arrhythmias.
• Echocardiogram: Left ventricular dilation, reduced ejection fraction, segmental wall motion abnormalities.
• Cardiac MRI: Evaluates myocardial fibrosis and residual viability.
• Coronary angiography: Essential for identifying critical coronary stenosis.

Treatment of Ischemic Dilated Cardiomyopathy

The treatment aims to **improve ventricular function, reduce symptoms, and prevent disease progression**.

Lifestyle Modifications: A low-sodium diet, controlled physical activity, smoking cessation, and blood pressure management improve prognosis.

Pharmacological Therapy:

• ACE inhibitors and ARBs: Reduce afterload and ventricular remodeling.
• Beta-blockers: Improve ventricular function and reduce mortality.
• Aldosterone antagonists: Prevent myocardial fibrosis.
• Diuretics: Manage pulmonary and peripheral congestion.
• Anticoagulants: Essential in patients with atrial fibrillation or intracardiac thrombi.

Myocardial Revascularization: In patients with significant ischemia, **coronary revascularization** through **percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG)** may improve ventricular function.

Advanced Therapy: In patients with **advanced heart failure**, additional interventions may be required:

• Implantable cardioverter-defibrillator (ICD) for sudden cardiac death prevention.
• Cardiac resynchronization therapy (CRT) in patients with ventricular dyssynchrony.
• Heart transplantation in severe cases.

Prognosis and Complications

Ischemic dilated cardiomyopathy is a **progressive condition** with a high risk of **refractory heart failure, ventricular arrhythmias, and sudden cardiac death**. However, **optimized treatment can significantly improve quality of life and survival**.

References
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