Dilated Cardiomyopathy Overview

Study Notes

Characterized by progressive cardiac dilation and systolic dysfunction, resulting in ineffective heart contraction.
Genetic causes account for 20-50% of cases, with dystrophin mutations being the most common.
Contributing factors include viral myocarditis, alcohol or toxic exposure, peripartum cardiomyopathy, and iron overload.
The heart appears enlarged (2-3 times normal size) and flabby upon inspection, with mural thrombi common.
Histological features include hypertrophied muscle cells, irregularities, and varying degrees of interstitial and endocardial fibrosis.
Clinical significance includes a typical ejection fraction of less than 25% in end-stage cases, with half of patients dying within 2 years.
Cardiac transplantation is the only definitive treatment.

A distinct primary myocardial disease characterized by myocardial hypertrophy, poorly compliant left ventricular myocardium, and defective diastolic filling.
Systolic function remains typically preserved despite primary diastolic dysfunction.
Completely genetic in origin, involving mutations in genes encoding contractile apparatus proteins, with autosomal dominant inheritance.
Prognosis varies widely and closely correlates with specific genetic mutations.
Macroscopically, there is disproportionate thickening of the ventricular septum compared to the left ventricle free wall.
Histological findings include myocyte hypertrophy and myofiber disarray, with interstitial and replacement fibrosis.
Clinical complications include reduced stroke volume, possible dynamic obstruction to left ventricular outflow, and atrial fibrillation leading to thrombus formation and stroke.
This condition is a common cause of sudden unexplained death in young athletes, but pharmacologic intervention can mitigate risks.

Endomyocardial fibrosis affects young individuals in tropical regions, causing fibrosis from the apex upward, involving heart valves with an unknown etiology.
Loeffler endocarditis presents similarly but is associated with eosinophilia and is relevant in myeloproliferative diseases; treatment with tyrosine kinase inhibitors can reverse fatal conditions.
Endocardial fibroelastosis features fibroelastic thickening of the left ventricular endocardium, often observed in early childhood and linked to congenital cardiac issues or various past insults.

Cardiomyopathies are specific diseases that lead to myocardial dysfunction, categorized into dilated, hypertrophic, and restrictive types.
Each type has distinct pathological and clinical features, requiring understanding of underlying mechanisms and treatment options to manage effectively.

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