5th July 2026

Aetiology

DCM encompasses a heterogeneous variety of genetic or acquired disorders that result in the same phenotype. They are not, however, mutually exclusive. The presence of environmental risk factors such as pregnancy, viral myocarditis or reported excessive alcohol intake can aggravate the expression of DCM in patients who carry a pathogenic gene variant. It is imperative to mention that the diagnosis of “idiopathic DCM” should only be established after ruling out acquired causes, as some causes may be reversible. A detailed list of acquired, non-genetic causes of DCM are described in Table 2. 

Inherited causes 

Idiopathic or familial DCM account for approximately 30-40% of cases of DCM, with the most common pattern of inheritance being autosomal dominant. Nevertheless, the true prevalence of familial DCM may be underestimated due to variable clinical presentation and incomplete penetrance. A negative family history does not exclude a genetic form of DCM due to the presence of de novo mutations. The most commonly described genetic mutations involve genes that encode proteins of the cardiac myocyte, including titin, lamin A, filamin C, dystrophin and phospholamban. 

Acquired causes

• Cardiovascular 
  • Chronic hypertension increases afterload, which can lead to left ventricular hypertrophy and subsequent dilation, impairing cardiac output. 
  • MI results in scar formation and remodelling, which can weaken the heart muscle and lead to dilation. 
  • Chronic ischaemia from CHD can cause myocardial damage and remodelling, leading to heart muscle weakening. This can also be the result of vasculitis.

• Infective
  • Viral causes include HIV, which can cause direct viral infection of the myocardium, result in opportunistic infections, or side effects of antiretroviral therapy. Myocarditis may also be a complication following coxsackievirus infection, leading to dilation. 
  • Common viral causes: HIV, adenovirus, parvovirus B19, herpes viruses, echovirus, enterovirus, SARS-CoV-2
  • Bacterial: Lyme disease
  • Mycobacterial
  • Parasitic: Chagas disease
  • Fungal
• Drug-related
  • Recreational drugs such as cocaine and methamphetamines, or toxins including cobalt, moreover, have direct toxic effects on the myocardium and can induce severe hypertension and vasospasm. 
  • Alcohol excess is toxic to the myocardium, leading to oxidative stress and cellular apoptosis and may result in deficiencies in essential nutrients like thiamine; these metabolic disturbances can lead to impaired myocardial energy production.
  • Anabolic steroids
  • Systemic anti-cancer treatment: doxorubicin, trastuzumab, and immune checkpoint inhibitors. Anthracyclines, CAR-T therapy
• Pregnancy
  • May occur during pregnancy or postpartum. 
• Endocrine
  • Hypo- and hyperthyroidism – high output cardiac failure, bradycardia, decreased cardiac contractility
  • Cushing/Addison disease
  • Phaeochromocytoma
  • Acromegaly
  • Diabetes Mellitus
• Systemic conditions
  • Giant cell myocarditis
  • Inflammatory (biopsy-proven, non-infectious myocarditis)
  • Eosinophilic granulomatosis with polyangiitis
  • Sarcoidosis
  • Systemic lupus erythematosus
  • Rheumatoid arthritis
  • Haemochromatosis
  • Sarcoidosis  
• Nutritional deficiencies
  • Thiamine deficiency (Beri-beri)
  • Zinc, copper and selenium deficiency 
  • Carnitine deficiency
• Electrolyte disturbances
  • Hypocalcaemia
  • Hypophosphatemia