Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is left or biventricular dilatation with systolic dysfunction not explained by coronary disease, hypertension, valve disease or congenital heart disease.

Prevalence is about 1 in 250 to 500. Familial in 30 to 50%, autosomal dominant mainly, with TTN truncating variants (15 to 25%), LMNA, MYH7, BAG3, DSP, RBM20, FLNC, desmin.

Acquired causes: viral myocarditis, alcohol, anthracyclines, trastuzumab, immune checkpoint inhibitors, cocaine, amphetamines, peripartum cardiomyopathy, tachycardia induced cardiomyopathy, thyroid disease, haemochromatosis, nutritional deficiency (thiamine, selenium), HIV, Chagas disease, sarcoidosis, autoimmune disease.

Prognosis: 5 year transplant free survival about 70 to 80% with modern therapy. LMNA, FLNC and DSP carriers have high arrhythmic risk.

• Dyspnoea, fatigue, oedema, orthopnoea, palpitations, syncope.
• Thromboembolism, arrhythmia, sudden death.
• Displaced apex, S3 gallop, functional mitral and tricuspid regurgitation, raised venous pressure.
• Extracardiac features guide genetics (skeletal myopathy, conduction disease, deafness).

• Echocardiography: dilated, hypokinetic ventricle, ejection fraction usually below 45%.
• Cardiac MRI: exclude ischaemia, characterise fibrosis (mid wall late gadolinium enhancement predicts sudden death), myocarditis, infiltrative disease.
• Coronary angiography or CT angiography.
• ECG, Holter, NT proBNP, troponin, ferritin and transferrin saturation, TSH, HIV, creatine kinase, autoimmune screen, toxicology.
• Genetic testing with panel in all patients, and cascade screening of first degree relatives with ECG and echocardiogram.
• Endomyocardial biopsy for fulminant onset, giant cell myocarditis or eosinophilic disease.

• Remove reversible causes: abstain from alcohol, treat tachycardia (rate or rhythm control, ablation), stop cardiotoxic drugs, replace thiamine (100 mg daily), correct thyroid disorder.
• Guideline directed therapy: sacubitril/valsartan 24/26 mg to 97/103 mg twice daily, bisoprolol 10 mg or carvedilol 25 mg twice daily, spironolactone 25 to 50 mg, dapagliflozin 10 mg daily, loop diuretics, ivabradine.
• Anticoagulation for atrial fibrillation (apixaban 5 mg twice daily), prior thromboembolism or intracardiac thrombus.
• ICD for ejection fraction 35% or less on therapy, or earlier in high risk genotypes (LMNA with risk factors: ICD at ejection fraction under 45%). CRT for left bundle branch block with QRS 150 ms or more.
• Ablation of ventricular tachycardia; amiodarone for symptomatic arrhythmia.
• Left ventricular assist device and transplantation for end stage disease.
• Immunosuppression only for proven inflammatory cardiomyopathy (giant cell, sarcoid).
• Vaccination, rehabilitation, avoid NSAIDs, pregnancy counselling. About 25 to 40% show left ventricular recovery.