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# Dilated cardiomyopathy

In dilated cardiomyopathy the ventricles enlarge and pump weakly, leading to heart failure. In Latin America Chagas disease is a key cause.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Left ventricle](https://durgical.com/en/anatomy/left-ventricle/)
- [Right ventricle](https://durgical.com/en/anatomy/right-ventricle/)
- [Left atrium](https://durgical.com/en/anatomy/left-atrium/)
- [Mitral anterior leaflet](https://durgical.com/en/anatomy/anterior-leaflet-of-left-atrioventricular-valve/)
- [Left ventricle papillary muscles](https://durgical.com/en/anatomy/superior-papillary-muscle-of-left-ventricle/)
- [Bundle branches](https://durgical.com/en/anatomy/right-bundle-branch/)

## In the clinical exam

- [Precordial inspection and palpation: apex beat, heaves and thrills](https://durgical.com/en/clinical-exam/precordial-inspection-and-palpation-apex-beat-heaves-and-thrills/)
- [Heart failure syndrome: left- and right-sided signs](https://durgical.com/en/clinical-exam/heart-failure-syndrome-left-and-right-sided-signs/)

## Why it happens

- [Hypertrophy: physiologic and pathologic](https://durgical.com/en/general-pathology/hypertrophy-physiologic-and-pathologic/)
- [Mendelian inheritance: autosomal dominant, recessive and X-linked](https://durgical.com/en/general-pathology/mendelian-inheritance-autosomal-dominant-recessive-and-x-linked/)
- [Alcohol: how it injures the liver, brain, heart and fetus](https://durgical.com/en/general-pathology/alcohol-how-it-injures-the-liver-brain-heart-and-fetus/)
- [Systemic (arterial) thromboembolism](https://durgical.com/en/general-pathology/systemic-thromboembolism/)
- [Heart failure physiology](https://durgical.com/en/physiology/heart-failure-physiology/)
- [The Frank–Starling mechanism](https://durgical.com/en/physiology/the-frank-starling-mechanism/)

## Show 2 more

- [Preload, afterload and contractility](https://durgical.com/en/physiology/preload-afterload-and-contractility/)
- [Cardiac muscle: intercalated discs](https://durgical.com/en/histology/cardiac-muscle-intercalated-discs/)

## What it is

A heart muscle disease with dilation and reduced systolic function of the [left ventricle](https://durgical.com/en/anatomy/left-ventricle/), or both ventricles, not explained by coronary artery disease or abnormal loading conditions. It is a leading cause of heart failure and heart transplantation.

## Who gets it

A common cardiomyopathy in adults. In Colombia and other Latin American countries, Chagas disease is an important cause of dilated cardiomyopathy, and up to a third of people with chronic Trypanosoma cruzi infection develop heart involvement decades later.

## Causes

- Genetic (for example titin and lamin A/C mutations) or idiopathic
- Chagas disease (Trypanosoma cruzi), important in Latin America
- Viral myocarditis
- Toxic: alcohol, cocaine, anthracycline chemotherapy and trastuzumab
- Peripartum cardiomyopathy
- Tachycardia-induced, thyroid disease and thiamine deficiency (wet beriberi)

## Risk factors

- Family history of cardiomyopathy or sudden death
- Heavy alcohol use
- Living or having lived in Chagas-endemic areas
- Previous cardiotoxic chemotherapy
- Late pregnancy and the months after delivery

## Pathophysiology

Loss or dysfunction of myocytes reduces contractility. The ventricle dilates to keep stroke volume (eccentric remodelling), wall stress rises, and neurohormonal systems (renin-angiotensin-aldosterone, sympathetic) are activated, causing fluid retention and further remodelling. Annular dilation produces functional mitral regurgitation, and scar and stretch favour arrhythmias and mural thrombi.

## Classification

- By cause: genetic/familial, inflammatory, toxic, infectious (Chagas), peripartum, tachycardia-induced, idiopathic
- Heart failure class (NYHA I to IV) and stage (ACC/AHA A to D)

## Symptoms and signs

- Exertional dyspnoea, orthopnoea and paroxysmal nocturnal dyspnoea
- Fatigue and reduced exercise tolerance
- Leg oedema, weight gain and abdominal swelling
- Palpitations and syncope from arrhythmias
- S3 gallop, displaced apex beat and a mitral regurgitation murmur
- Embolic events (stroke) from ventricular or atrial thrombus

## Red flags

- Syncope or sustained ventricular arrhythmias
- Rest dyspnoea, hypotension or signs of low output
- Rapid weight gain and worsening oedema
- New heart failure in late pregnancy or after delivery

## Diagnosis

**Clinical**
Signs and symptoms of heart failure with a search for the cause: family history, alcohol and drug use, chemotherapy, recent viral illness, pregnancy, and residence in Chagas-endemic areas.

**Tests**
ECG (bundle branch block, arrhythmias; [right bundle branch](https://durgical.com/en/anatomy/right-bundle-branch/) block with left anterior fascicular block suggests Chagas), natriuretic peptides, troponin, thyroid function, iron studies, Chagas serology when relevant, Holter; genetic testing when familial disease is suspected.

**Imaging**
Echocardiography shows dilated ventricles with reduced ejection fraction and often functional mitral regurgitation; cardiac MRI characterises fibrosis and inflammation; coronary angiography or CT excludes ischaemic cardiomyopathy.

## Differential diagnosis

- Ischaemic cardiomyopathy
- Valvular heart disease (severe aortic or mitral regurgitation)
- Hypertensive heart disease
- Myocarditis
- Restrictive or infiltrative cardiomyopathy

## Goal of treatment

Relieve congestion, block the neurohormonal pathways that drive remodelling, treat reversible causes, prevent sudden death and thromboembolism, and improve survival.

## Treatment

**Medical**
Guideline-directed therapy for reduced ejection fraction: ACE inhibitors, ARBs or an angiotensin receptor-neprilysin inhibitor; beta-blockers; mineralocorticoid receptor antagonists; SGLT2 inhibitors.

**Medical**
Loop diuretics for congestion, and anticoagulation when there is atrial fibrillation or intracardiac thrombus.

**Medical**
Treatment of the cause: stopping alcohol or cardiotoxic drugs, controlling tachyarrhythmias and thyroid disease, thiamine replacement, and antiparasitic treatment in Chagas when indicated.

**Procedure**
Implantable cardioverter-defibrillator when ejection fraction stays very low despite treatment, and cardiac resynchronisation therapy with left bundle branch block and a wide QRS.

**Surgical**
Left ventricular assist device or heart transplantation for advanced heart failure.

**Lifestyle**
Salt and fluid advice, daily weight, physical activity adapted to the patient, vaccination, and avoiding alcohol.

**Follow-up**
Regular echocardiography, [kidney](https://durgical.com/en/anatomy/kidney/) function and potassium on neurohormonal drugs, and family screening in genetic forms.

## Complications

- Progressive heart failure and cardiogenic shock
- Ventricular arrhythmias and sudden cardiac death
- Atrial fibrillation
- Stroke and systemic embolism from mural thrombus
- Functional mitral and tricuspid regurgitation

## Prognosis

Variable. Modern drug and device therapy has improved survival, and some forms (alcohol, peripartum, tachycardia-induced) can recover substantially. Chagas cardiomyopathy tends to have a worse prognosis than other causes.

## Prevention

- Avoiding heavy alcohol use and stimulant drugs
- Cardiac monitoring during cardiotoxic chemotherapy
- Vector control and screening for Chagas in endemic areas, and screening of pregnant women and blood donors
- Screening relatives in familial forms

## Test yourself

Think of the answer, then tap the question to see it.

## What defines dilated cardiomyopathy?

Ventricular dilation with reduced systolic function not explained by coronary artery disease or abnormal loading conditions.

## Which infectious cause of dilated cardiomyopathy is characteristic of Latin America?

Chagas disease (Trypanosoma cruzi).

## Which are the main drug classes of guideline-directed therapy for reduced ejection fraction?

ACE inhibitor, ARB or ARNI; beta-blocker; mineralocorticoid receptor antagonist; and SGLT2 inhibitor.

## Which ECG pattern suggests Chagas cardiomyopathy?

Right bundle branch block with left anterior fascicular block.

## Which toxic causes of dilated cardiomyopathy are classic in exams?

Alcohol, cocaine, anthracyclines and trastuzumab.

[Add to my cards (5)](https://durgical.app/estudiar/?add=/en/conditions/dilated-cardiomyopathy/)

## Related conditions

- [Heart failure](https://durgical.com/en/conditions/heart-failure/)
- [Chagas cardiomyopathy](https://durgical.com/en/conditions/chagas-cardiomyopathy/)
- [Chagas disease](https://durgical.com/en/conditions/chagas-disease/)
- [Ventricular tachycardia](https://durgical.com/en/conditions/ventricular-tachycardia/)
- [Atrial fibrillation](https://durgical.com/en/conditions/atrial-fibrillation/)
- [Mitral regurgitation](https://durgical.com/en/conditions/mitral-regurgitation/)
- [Cardiac arrest (VF, pulseless VT, asystole, PEA)](https://durgical.com/en/conditions/cardiac-arrest/)
- [Myocardial Infarction (Heart Attack)](https://durgical.com/en/conditions/myocardial-infarction/)
- [Hypertrophic cardiomyopathy](https://durgical.com/en/conditions/hypertrophic-cardiomyopathy/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Dilated cardiomyopathy: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/000168.htm) (MedlinePlus, US National Library of Medicine, 2026); [Chagas disease (also known as American trypanosomiasis)](https://www.who.int/news-room/fact-sheets/detail/chagas-disease-(american-trypanosomiasis)) (World Health Organization, 2026).

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Source: https://durgical.com/en/conditions/dilated-cardiomyopathy/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/dilated-cardiomyopathy/