---
title: Dilated cardiomyopathy
description: What dilated cardiomyopathy is, why it develops, how it is detected and which treatment approaches clinical guidelines describe.
type: disease
preset: heart-failure
aliases:
  - DCM
sources:
  - tier: guideline
    org: esc
    title: 2023 ESC Guidelines for the management of cardiomyopathies
    year: 2023
    doi: 10.1093/eurheartj/ehad194
    url: https://doi.org/10.1093/eurheartj/ehad194
  - tier: guideline
    org: minzdrav-rf
    title: Дилатационная кардиомиопатия
    year: 2025
    url: https://cr.minzdrav.gov.ru/view-cr/1008_1
  - tier: reference
    org: statpearls
    title: Dilated Cardiomyopathy
    year: 2023
    url: https://www.ncbi.nlm.nih.gov/books/NBK441911/
sources_checked: 2026-10-11
review: null
---

Dilated cardiomyopathy (DCM) is a genetic or acquired disease of the heart muscle in which the <Structure id="left-ventricle">left ventricle</Structure> (or both ventricles) becomes enlarged and contracts less well.<Cite n={2} /> These changes cannot be explained only by coronary artery disease, high blood pressure or valve disease.<Cite n={[1, 2]} /> DCM is the most common cardiomyopathy.<Cite n={2} />

<Diagram name="dilated-cardiomyopathy">
  <p slot="normal">
    Normally the left ventricle is not enlarged and its ejection fraction is not reduced; DCM is
    diagnosed by exactly these two changes, enlargement and a reduced ejection fraction.<Cite
      n={2}
    />
  </p>
  <p slot="disease">
    In DCM the left ventricle, and sometimes both ventricles, are enlarged and contract less
    strongly.<Cite n={[1, 2]} /> The left ventricular ejection fraction is reduced: markedly (40% or
    less) or moderately (41–49%).<Cite n={2} />
  </p>
</Diagram>

## Why it happens

<Patient>

DCM can be inherited: 20–40% of cases run in families.<Cite n={2} /> It can also be caused by other factors.<Cite n={[2, 3]} /> Among infections, the strongest link has been found with a viral (enterovirus) infection, and inflammation of the heart muscle (myocarditis) can lead to DCM.<Cite n={[2, 3]} /> One of the most important causes worldwide is long-term heavy drinking.<Cite n={2} /> Long-term cocaine use and some medicines, above all anthracyclines, can also cause it.<Cite n={2} /> DCM can also develop in connection with pregnancy (peripartum cardiomyopathy).<Cite n={3} />

</Patient>

<Student>

The European guideline defines DCM as LV dilatation with global or regional systolic dysfunction unexplained solely by abnormal loading conditions (hypertension, valve disease, congenital heart disease) or coronary artery disease.<Cite n={1} /> In DCM the structure and function of the right ventricle are affected primarily (by direct involvement of RV myocardium) and secondarily.<Cite n={2} />

DCM is familial in 20–40% of cases.<Cite n={2} /> Among infections, the strongest link is with enterovirus infection; autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus and systemic sclerosis are rare causes, accounting for 5–10% of cases.<Cite n={2} /> Other secondary causes include chronic alcohol intoxication, long-term cocaine use and medicines, first of all anthracyclines.<Cite n={2} />

The incidence of DCM is estimated at 5–7.5 cases per 100,000 people per year and the prevalence at 13.1–36.5 per 100,000.<Cite n={2} /> The European guideline gives an adult prevalence of 0.036–0.400%.<Cite n={1} />

</Student>

## Symptoms

<Patient>

In a person with DCM the heart contracts less well, but there may be no obvious symptoms of heart failure.<Cite n={3} /> When symptoms do occur, they are usually signs of heart failure: breathlessness, breathlessness when lying flat, attacks of breathlessness at night, tiring easily, and swelling of the shins and ankles.<Cite n={[2, 3]} />

Heart rhythm disturbances are common.<Cite n={2} /> Because of enlarged chambers and arrhythmias, blood clots can form in the heart and travel with the blood into the vessels.<Cite n={2} /> Sudden cardiac death can occur.<Cite n={2} />

</Patient>

<Student>

The clinical picture is dominated by heart failure symptoms: dyspnoea, orthopnoea, paroxysmal nocturnal dyspnoea, fatigue, and swelling of the shins and ankles.<Cite n={2} /> Ventricular arrhythmias are found in 40–50% of cases and atrial fibrillation in 15–30% of patients.<Cite n={2} /> Chamber dilatation and arrhythmias lead to thromboembolic complications in 1–6% of patients; sudden cardiac death occurs in about 12% of patients with DCM.<Cite n={2} />

</Student>

## How it is diagnosed

<Patient>

The main test is a heart ultrasound (echocardiography), which is done for everyone suspected of having DCM.<Cite n={[2, 3]} /> It shows the size of the ventricles and how they contract.<Cite n={3} /> An ECG is also recommended for everyone with DCM.<Cite n={2} />

The doctor asks in detail about illnesses in the family: whether relatives have had DCM, sudden death or fainting.<Cite n={2} /> Relatives of a person with DCM may have a related heart muscle disease in which the ventricle is not enlarged.<Cite n={2} />

</Patient>

<Student>

According to the Russian Ministry of Health guideline, the diagnosis is based on structural and functional changes of the heart not caused by ischaemia, heart defects or hypertension; one criterion is a markedly (≤40%) or moderately (41–49%) reduced left ventricular ejection fraction.<Cite n={2} />

Echocardiography is recommended for all patients with suspected DCM to confirm the diagnosis and define the phenotype; a 12-lead ECG is recommended for all patients with DCM.<Cite n={2} /> The ECG may show nonspecific ST-segment and T-wave abnormalities.<Cite n={3} /> The European guideline advises multimodality imaging to characterise the phenotype.<Cite n={1} />

A family history should be taken in all patients with suspected DCM: DCM, sudden cardiac death, syncope, pacemaker implantation, stroke at a young age and systemic diseases in relatives.<Cite n={2} /> A three- to four-generation family pedigree helps to identify Mendelian forms of inheritance.<Cite n={1} /> Relatives of a patient with DCM may have non-dilated left ventricular cardiomyopathy.<Cite n={2} />

</Student>

## How it is treated

<Patient>

DCM is treated on the same principles as heart failure.<Cite n={3} /> Treatment includes medicines and non-drug methods.<Cite n={2} /> Which treatment is right is decided by the doctor together with the patient.

To prevent sudden death, an implantable cardioverter-defibrillator may be considered for some people.<Cite n={3} /> Cardiac resynchronisation therapy may also be considered for some people.<Cite n={3} /> If the disease does not respond to all available treatment, a heart transplant is considered.<Cite n={3} />

</Patient>

<Student>

The management of DCM is consistent with standard heart failure guidelines.<Cite n={3} /> Disease-modifying therapy in DCM consists of drug therapy and non-drug interventions.<Cite n={2} />

Implantable cardioverter-defibrillators for primary prevention of sudden cardiac death and cardiac resynchronisation therapy can be considered and are recommended by the heart failure guidelines.<Cite n={3} /> Patients with disease refractory to maximum medical therapy should be considered for cardiac transplantation.<Cite n={3} /> The European guideline stresses that care for patients with cardiomyopathy requires the collaboration of different specialties.<Cite n={1} />

</Student>

## When to call an ambulance

DCM can lead to dangerous arrhythmias, thromboembolism and sudden cardiac death.<Cite n={2} /> If a person with DCM faints, suddenly finds it much harder to breathe, especially when lying down, or has severe chest pain or a fast heartbeat with feeling faint, call your local emergency number (112 in the EU, 911 in the US and Canada, 999 in the UK).

<Quiz />