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Dilated Cardiomyopathy (DCMP)

Clinical Subject Page

Dilated Cardiomyopathy (DCMP)

Also called

Congestive Cardiomyopathy (Old)

ICD-10

I42.0

Specialty

Cardiology

Onset

Chronic

Reviewed

June 2026

On This Page

Overview

Dilated cardiomyopathy (DCM/DCMP) is a myocardial disease characterized by dilation of one or both ventricles with reduced systolic function (LVEF <40–50%), in the absence of abnormal loading conditions or coronary artery disease sufficient to explain the dysfunction.

Etiology & Risk Factors

Etiology of Dilated Cardiomyopathy :

  • Idiopathic (most common)
  • Genetic (familial DCM)
  • Viral myocarditis (e.g., Coxsackie B, adenovirus)
  • Alcohol abuse
  • Chemotherapy (doxorubicin, trastuzumab)
  • Peripartum cardiomyopathy
  • Autoimmune diseases
  • Endocrine disorders (thyroid disease, diabetes)
  • Nutritional deficiencies (thiamine, selenium)
  • Tachycardia-induced cardiomyopathy

Risk Factors for Dilated Cardiomyopathy :

  • Family history of cardiomyopathy
  • Hypertension
  • Excessive alcohol intake
  • Smoking
  • Cocaine and illicit drug use
  • Previous myocarditis
  • Cancer chemotherapy
  • Pregnancy (peripartum)
  • Metabolic disorders

Pathophysiology

Myocardial injury/genetic defect
↓
Ventricular dilation
↓
Reduced contractility
↓
↓ Stroke volume & ↓ Ejection fraction
↓
Neurohormonal activation (RAAS & SNS)
↓
Fluid retention + Ventricular remodeling
↓
Heart failure (HFrEF)
↓
Mitral regurgitation + Arrhythmias + Thrombus formation

Clinical Presentation

Symptoms of Dilated Cardiomyopathy :

  • Progressive exertional dyspnea
  • Orthopnea
  • Paroxysmal nocturnal dyspnea
  • Fatigue
  • Reduced exercise tolerance
  • Peripheral edema
  • Palpitations
  • Syncope (advanced disease)

Signs of Dilated Cardiomyopathy :

  • Tachycardia
  • Elevated JVP
  • S3 gallop
  • Displaced, diffuse apex beat
  • Functional mitral regurgitation murmur
  • Bibasal crackles
  • Hepatomegaly
  • Peripheral edema

History Taking

Key Questions:

  • When did the symptoms begin?
  • Is dyspnea worsening?
  • Orthopnea or PND?
  • Chest pain?
  • Palpitations?
  • Syncope?
  • Alcohol intake?
  • Recreational drug use?
  • Chemotherapy history?
  • Recent viral illness?
  • Family history of sudden cardiac death or cardiomyopathy?

Red Flags:

  • Syncope
  • Sustained ventricular arrhythmias
  • Cardiogenic shock
  • Sudden worsening heart failure

Investigations

Laboratory

  • CBC
  • Electrolytes
  • Renal function
  • Liver function
  • BNP/NT-proBNP
  • Troponin
  • Thyroid function
  • Iron studies
  • Viral/autoimmune tests (selected patients)

ECG:

  • Sinus tachycardia
  • Left bundle branch block (LBBB)
  • Atrial fibrillation
  • Ventricular arrhythmias
  • Nonspecific ST-T changes

Imaging:

  • Chest X-ray
    • Cardiomegaly
    • Pulmonary congestion
  • Echocardiography (gold standard)
    • Dilated LV
    • Reduced LVEF
    • Global hypokinesia
    • Functional MR
  • Cardiac MRI
    • Myocardial fibrosis
    • Myocarditis evaluation

Additional Tests:

  • Coronary angiography/CT coronary angiography
  • Genetic testing (familial disease)
  • Endomyocardial biopsy (selected cases)

Diagnosis

Diagnosis is based on:

  • Clinical features of heart failure
  • Echocardiographic evidence of ventricular dilation with reduced systolic function
  • Exclusion of significant coronary artery disease or abnormal loading conditions
  • Identification of an underlying cause when possible
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Dilated Cardiomyopathy (DCM) · Diagnostic Criteria

Diagnostic Criteria — all components required
1
Clinical features of heart failure
Presence of symptoms and signs consistent with HF — dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea, fatigue, and peripheral oedema. Examination may reveal elevated JVP, S3 gallop, displaced apex beat, and pulmonary crackles. Severity often graded using NYHA functional class.
Some patients may be asymptomatic at diagnosis — identified incidentally on imaging or during family screening.
2
Echocardiographic evidence of ventricular dilation with reduced systolic function
Left ventricular end-diastolic diameter (LVEDD) increased beyond normal reference range for body surface area, accompanied by reduced ejection fraction LVEF <40%. Global hypokinesia is typical rather than regional wall motion abnormality. Right ventricle may also be involved in advanced disease.
Cardiac MRI can complement echo — useful for tissue characterisation (fibrosis pattern) and confirming chamber dimensions when echo windows are poor.
3
Exclusion of significant coronary artery disease or abnormal loading conditions
Coronary angiography or CT coronary angiography to rule out obstructive CAD as the cause of LV dysfunction (i.e. ischaemic cardiomyopathy). Must also exclude abnormal loading conditions — significant valvular disease (severe MR, AR, AS) and uncontrolled systemic hypertension — that could independently explain the dilation and dysfunction.
This exclusion step is essential — DCM is a diagnosis of exclusion once secondary causes have been ruled out.
4
Identification of an underlying cause when possible
Comprehensive workup for aetiology: family history and genetic testing (30–50% familial), viral serology / endomyocardial biopsy (myocarditis), alcohol and substance use history, peripartum status, autoimmune screen, thyroid function, iron studies (haemochromatosis), and review of cardiotoxic medication exposure (e.g. anthracyclines).
Genetic / Familial Viral myocarditis Alcohol-induced Peripartum Tachycardia-induced Cardiotoxic drugs Autoimmune Idiopathic
Identifying a treatable cause (e.g. tachycardia-induced, alcohol-induced) can lead to partial or complete recovery of LV function — making this step clinically important, not just academic.

Management

Lifestyle

  • Salt restriction
  • Fluid restriction (selected patients)
  • Alcohol cessation
  • Smoking cessation
  • Regular exercise as tolerated
  • Vaccinations
  • Family screening if inherited

Medications (Guideline-Directed Medical Therapy)

  • ARNI (preferred) or ACE inhibitor/ARB
  • Evidence-based β-blocker
  • Mineralocorticoid receptor antagonist (MRA)
  • SGLT2 inhibitor
  • Loop diuretics for congestion
  • Anticoagulation if atrial fibrillation or LV thrombus

Devices

  • ICD for prevention of sudden cardiac death
  • CRT for selected patients with LBBB and reduced EF

Advanced Therapy

  • LVAD
  • Heart transplantation

Complications

  • Heart failure progression
  • Atrial fibrillation
  • Ventricular tachycardia/fibrillation
  • Sudden cardiac death
  • Functional mitral regurgitation
  • Left ventricular thrombus
  • Stroke/systemic embolism
  • Cardiogenic shock

Prognosis

  • Variable depending on etiology and response to therapy
  • Many patients improve with modern GDMT
  • Poor prognosis with severe LV dysfunction or recurrent ventricular arrhythmias
  • Advanced disease may require transplantation

Key Points / Clinical Pearls

  • Dilated Cardiomyopathy is the most common cause of HFrEF.
  • Echocardiography is the first-line imaging modality.
  • Exclude ischemic heart disease before diagnosing idiopathic DCM.
  • Early guideline-directed medical therapy improves survival.
  • ICD reduces the risk of sudden cardiac death in eligible patients.
  • Consider genetic testing and family screening in familial Dilated Cardiomyopathy.
  • Mahmaljy H, Yelamanchili VS, Singhal M. National Center for Biotechnology Information (NIH). Dilated Cardiomyopathy, StatPearls.
  • Arbelo E, Protonotarios A, Gimeno JR, et al. 2023 ESC Guidelines for the Management of Cardiomyopathies. Eur Heart J. 2023;44:3503-3626. doi: 10.1093/eurheartj/ehad194.
  • MedlinePlus, National Library of Medicine (NIH). Dilated Cardiomyopathy: Medical Encyclopedia.
  • Diagnosis and Management of Dilated Cardiomyopathy: A Systematic Review of Clinical Practice Guidelines and Recommendations. Eur Heart J. PMID: 39674807.
  • Heidenreich PA, Bozkurt B, Aguilar D, et al. 2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure. Circulation. 2022;145:e895-e1032. PMID: 35363499.