Summary

Dilated Cardiomyopathy (DCM) is a myocardial disease characterised by left ventricular or biventricular dilation and systolic dysfunction in the absence of coronary artery disease, valvular disease, or other causes sufficient to explain the degree of dysfunction. DCM is the most common cardiomyopathy and a leading indication for heart transplantation. Genetic mutations account for 30-50% of cases, with titin (TTN) mutations being the most prevalent. Treatment follows standard HFrEF guidelines, with emphasis on genetic testing, family screening, and consideration of advanced therapies for refractory cases.

Key Facts

• Definition: LV or biventricular dilation with EF under 45% without sufficient CAD or valvular cause
• Prevalence: 1 in 250-500 adults; most common cardiomyopathy
• Genetic Contribution: 30-50% have identifiable genetic cause
• Most Common Gene: TTN (titin) mutations (20-25% of familial DCM)
• Prognosis: 5-year survival 50-80% depending on severity and treatment
• Treatment: Standard HFrEF therapy; genetic testing and family screening essential

Clinical Pearls

High-Yield Points:

• Always exclude reversible causes: alcohol, thyroid, tachycardia-induced, peripartum
• Genetic testing recommended for all DCM patients (ESC guidelines)
• First-degree relatives should be screened with echo
• TTN truncating variants are most common but may have better prognosis
• LMNA mutations have high arrhythmic risk - early ICD consideration
• Some patients recover EF with optimal therapy (especially recent-onset)

Why This Matters

DCM is a major cause of heart failure and sudden cardiac death, particularly in younger patients. Identifying reversible causes can lead to recovery. Genetic diagnosis enables cascade family screening, potentially identifying at-risk relatives before symptoms develop. Understanding the heterogeneous nature of DCM is essential for personalised management.

Key Findings

Cardiovascular:

• Displaced apex beat (lateral and inferior)
• S3 gallop (increased filling pressures)
• Pansystolic murmur at apex (functional MR)
• Elevated JVP with prominent v waves

Respiratory:

• Bibasal crackles
• Reduced air entry (pleural effusions)

Peripheral:

• Bilateral pitting oedema
• Cool extremities (low output)
• Hepatomegaly

Phenotypic Classification

By Aetiology

• Familial/Genetic: Positive family history or genetic test
• Post-inflammatory: Following documented myocarditis
• Alcoholic: History of chronic excess alcohol
• Peripartum: Develops in last month of pregnancy or 5 months postpartum
• Idiopathic: No cause identified

Key Guidelines

Key Recommendations

• Genetic testing for all DCM patients (Class I)
• Family screening for first-degree relatives (Class I)
• Standard HFrEF therapy for all with reduced EF (Class I)
• ICD for EF ≤35% after 3 months optimal therapy (Class I)

What is Dilated Cardiomyopathy?

Dilated cardiomyopathy is a condition where your heart muscle becomes stretched and weakened. The main pumping chamber (left ventricle) gets larger but weaker, so it cannot pump blood as efficiently.

What causes it?

• Genetics: About 30-50% of cases run in families
• Viral infections: Some people develop this after a heart infection
• Alcohol: Long-term heavy drinking can cause this
• Unknown: In many cases, we cannot find a specific cause

Why is genetic testing important?

If we find a genetic cause, we can test your family members to see if they might be at risk, even before they develop symptoms. Early detection leads to better outcomes.

How is it treated?

• Medications to support your heart and reduce stress on it
• Sometimes a pacemaker or defibrillator device
• In severe cases, a heart pump or transplant may be considered
• Lifestyle changes: no alcohol, healthy diet, appropriate exercise