Dilated Cardiomyopathy 💔

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💔 Dilated Cardiomyopathy (DCM) is a myocardial disease where the left ventricle becomes enlarged and poorly contracting, leading to impaired systolic function. It can affect both young and older adults. Diagnosis is usually by echocardiography showing LV dilatation + reduced EF.

📖 About

• Characterised by LV dilatation + reduced ejection fraction.
• Most cases are idiopathic (often post-viral), but many secondary causes exist.
• Before labelling “idiopathic DCM”, exclude IHD and hypertension.
• DCM is a leading cause of heart transplantation 🌱 worldwide.

⚠️ Causes

• Idiopathic – most common.
• 🦠 Infectious: Post-viral myocarditis, Chagas, HIV.
• 🍷 Toxins: Alcohol, cocaine, anthracyclines, trastuzumab.
• 🥗 Metabolic: Thiamine (B1), selenium deficiency.
• 🧬 Endocrine: Thyrotoxicosis, myxoedema, acromegaly, diabetes.
• 👨‍👩‍👧 Genetic: Familial, Duchenne/Becker, mitochondrial disorders.
• 🛡️ Autoimmune/infiltrative: SLE, sarcoidosis.
• 🤰 Pregnancy: Peripartum cardiomyopathy.

🧬 Genetics

• ~25% of cases are familial (often AD).
• 🔎 Family screening advised due to SCD risk.
• X-linked: Duchenne & Becker muscular dystrophy.
• Mitochondrial → think diabetes, deafness, epilepsy.

🩺 Clinical Presentation

• 🌬️ HF symptoms: Dyspnoea, fatigue, orthopnoea, PND.
• ⚡ Arrhythmias: AF common; VT ↑ risk of sudden death.
• 👂 Exam: S3/S4 gallop, displaced apex, pansystolic MR murmur.
• 🌊 Right HF: raised JVP, hepatomegaly, oedema.
• 🧨 Thromboembolism: mural thrombi → stroke/embolism.

🔬 Investigations

• Bloods: FBC, U&E, LFTs, troponin, CK, ESR/CRP, viral serology.
• Screen: Ferritin/iron (haemochromatosis), TFTs.
• ECG: AF, LBBB, LVH, Q waves, NSVT.
• Imaging: - 📸 CXR: Cardiomegaly + pulmonary congestion. - 🩻 Echo: Dilated LV, EF <45%, global hypokinesia ± thrombus. - 🧲 Cardiac MRI: Myocarditis, fibrosis.
• Coronary angiography: Exclude IHD before idiopathic Dx.

📊 Diagnostic Criteria (Idiopathic DCM)

• EF <45% OR fractional shortening <25%.
• LVEDD >112% predicted.
• Exclusion of other causes (HTN, IHD, alcohol, systemic disease).

⚠️ Complications

• 💔 End-stage HF.
• ⚡ Arrhythmias → AF, VT, sudden cardiac death.
• 🧨 Thromboembolism (stroke, systemic emboli).
• 🫀 Progression → transplant.

💊 Management

• 🌱 Lifestyle: stop alcohol, vaccines, genetic counselling.
• 💊 HF therapy: - Diuretics (symptoms) - ACEi/ARB/ARNI - Beta-blockers (carvedilol, bisoprolol) - MRA (spironolactone/eplerenone)
• ⚡ Arrhythmia: - Anticoagulation if AF/thrombus/EF very low - ICD if EF ≤35% despite therapy
• 🚑 Advanced: LVAD, cardiac transplant.

🔑 Exam Tip: Always exclude ischaemic heart disease before diagnosing “idiopathic DCM”. Look out for clues: chronic alcohol use, anthracycline chemotherapy, or family history.

📊 Rapid Comparison Table

📚 References

• Elliott – Diagnosis & management of dilated cardiomyopathy

🩺 Case 1 — Alcohol-Related DCM

A 55-year-old man with a long history of heavy alcohol intake presents with progressive exertional breathlessness, orthopnoea, and ankle swelling. On exam: displaced apex beat, S3 gallop, and bibasal crackles. Echo shows dilated LV with global hypokinesia and EF 25%. Management: 💊 Abstinence from alcohol, standard heart failure therapy (ACE inhibitors/ARNI, beta-blockers, MRAs, diuretics for congestion). Cardiology follow-up for device consideration if EF remains low. Avoid: ❌ Continuing alcohol use; avoid NSAIDs which worsen fluid retention and HF.

🩺 Case 2 — Peripartum DCM

A 32-year-old woman, 2 months postpartum, presents with fatigue, orthopnoea, and palpitations. Exam shows elevated JVP, bibasal crackles, and pedal oedema. Echo: dilated LV, EF 30%, no valvular disease. Management: 🏥 Standard heart failure therapy (diuretics, beta-blockers, ACE inhibitors if not pregnant/breastfeeding), anticoagulation if severe LV dysfunction, close follow-up with cardiology. Avoid: ❌ ACE inhibitors/ARBs during pregnancy or lactation; avoid further pregnancies until LV function recovers (risk of recurrence and mortality).

🩺 Case 3 — Familial/Genetic DCM

A 28-year-old man presents with syncope while exercising. His father died suddenly at 35. Exam: displaced apex, soft S1, and S3. ECG shows LBBB; echo reveals a dilated LV with EF 20%. Genetic testing confirms familial DCM. Management: 🚑 Standard HF therapy, consider ICD for primary prevention of sudden cardiac death. Genetic counselling and cascade screening for family. Avoid: ❌ Failure to screen relatives; avoid competitive sports due to arrhythmia risk.