creation date: 2025-10-20 16:25
tags: PathologiesIncomplete
Dilated Cardiomyopathy
Background
Definitions
Dilated cardiomyopathy (DCM) is a disease of the the heart muscles. It is characterized by the dilation and enlargement of one or both ventricles and impaired contractility and thus ejection fraction. DCM is generally progressive and leads to heart failure.
DCM can be primary or idiopathic or a secondary to another condition.
Etiology
The most common cause is idiopathic which likely involve familial or genetic predisposition with mutations affecting desmin (cytoskeletal), lamin C (nuclear membrane), or myosin (contractile proteins).
Secondary causes include:
- Infective myocarditis (eg. viral, Chagas disease, Lyme disease)
- Ischemic disease
- Hypertension
- Medication-induced (eg. anthracyclines)
- Alcohol abuse
- HIV
- Peripartum cardiomyopathy
- Infiltrative disease
It should be noted that ischemic cardiomyopathy and Takotsubo cardiomyopathy is occasionally described as a cause of DCM but are considered their own disease entities and discussed separately.
Pathogenesis
The exact mechanism that results in dilation depends on the etiology. In idiopathic etiology, the ventricle enlargement occurs due to abnormalities in the genes that encode for normal cardiomyocyte function and structure.
In secondary DCM, enlargement may occur secondary to left ventricular failure or to a primary cardiomyopathic process.
In either case, the progressive dilatation of the ventricles is associated with systolic and diastolic dysfunction causing increased end-systolic and end-diastolic volumes and thus reduced ejection fraction. Additionally, enlargement of the ventricles results in tricuspid and mitral valve insufficiency which further reduce ejection fraction.
Compensatory mechanisms results in myocardial remodelling which worsens injury.