5th July 2026

Dilated cardiomyopathy

• Prevalence: DCM affects approximately 1 in 250 to 1 in 500 adults globally. 
• Most common form of cardiomyopathy.
• Age: It can occur at any age, but is most commonly diagnosed in people between the ages of 20 and 60.
• Gender: It is more prevalent in men than in women.

Dilated cardiomyopathy (DCM) is characterised by the presence of left ventricular (LV) or biventricular dilatation and global systolic dysfunction (LVEF <50%) that cannot be solely determined by coronary artery disease or abnormal loading conditions. The prevalence of DCM is estimated to range from 1 in 2500 to 1 in 250 people, and disease onset is typically observed in the third or fourth decade of life. There is a predilection towards the male population, with a 3:1 ratio compared to females, and it is a leading cause for heart transplantation. 

Patients with DCM can present with signs of heart failure (shortness of breath, orthopnoea, paroxysmal nocturnal dyspnoea), arrhythmias (both atrial and ventricular), conduction blocks, or sudden cardiac death (SCD). These presentations are a late consequence of severe contractile dysfunction and biventricular remodelling that occur following a period of silent disease progression, where patients have been asymptomatic. To note, DCM patients with a genetic mutation to the lamin A/C protein, in particular, are predisposed to developing SCD from life-threatening ventricular arrhythmias regardless of the severity of LV dysfunction. This phenomenon highlights the importance of early disease detection through systematic genetic screening of a proband and their family members.

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 

Diagnosis

Signs and symptoms

Patients with DCM may present with symptoms of:

• cardiac failure: shortness of breath on exertion, orthopnoea, fatigue, paroxysmal nocturnal dyspnoea, abdominal discomfort, or leg swelling

Clinical signs that may be elicited on examination include: 

• bilateral basal crackles on lung auscultation
• hepatomegaly
• jugular venous distension
• peripheral oedema
• S3 gallop during rapid ventricular phase of diastole, indicating ventricular dilatation

Investigations

All patients with suspected DCM require a comprehensive diagnostic work-up to identify the aetiology and provide morphological and prognostic information. They include a detailed series of serological and genetic testing in addition to imaging modalities as described in Table 2. 

Table 2: List of investigations involved in the diagnostic workup of DCM. 

Management

General Management 

Generally speaking, patients with diagnosed DCM should restrict dietary intake of fluid (<1.5-2L fluid/day) and sodium (<5g/day). This is in addition to avoiding obvious precipitants such as alcohol and recreational drugs. Those with acquired causes of DCM require prompt treatment of the underlying metabolic, infective, endocrinological or electrolyte abnormality. 

High-intensity exercise, including competitive sport, is not recommended in symptomatic individuals, those with a left ventricular ejection fraction ≤40%, exercise-induced arrhythmias, or pathogenic variants in LMNA or TMEM43. 

Medical Management 

All patients with DCM should be treated according to established guidelines for the treatment of chronic heart failure. ACE inhibitors/angiotensin receptor blocker (ARB), angiotensin receptor-neprilysin inhibitor (ARNi), beta-blocker, mineralocorticoid receptor antagonist (MRA) and sodium-glucose co-transporter-2 (SGLT2) inhibitors are recommended to reduce hospitalisation and mortality. Moreover, loop diuretics provide symptomatic relief from fluid overload. 

Anticoagulation is advised in DCM patients with coexistent atrial fibrillation according to CHA2DS2-VA score to reduce thromboembolic risk. 

Patients with peripartum cardiomyopathy have a 50% chance of spontaneous recovery after delivery. However, they should be counselled regarding risk of potential recurrence even with recovery of LV function. Pregnancy is not advised in women with peripartum cardiomyopathy or DCM if LV function does not normalise. Beta-blockers and loop diuretics should be initiated carefully to the maximum tolerated dose while avoiding teratogenic agents (ACE inhibitors, ARB, ARNi, MRA) in this cohort of patients. 

Surgical Management

• ICDs
  • Patients with DCM and a high risk of sudden cardiac death, as determined by clinical risk stratification including cardiac risk factors, high-risk genotypes (especially so in those with LVEF=<35%), LVEF =<35% or in cardiac arrest or VT with haemodynamic compromise, may undergo implantation of an ICD for primary or secondary prevention of ventricular arrhythmias. However, particularly in young patients, ICDs can have several complications and may require multiple replacements.
• Cardiac Resynchronisation Therapy (CRT)/Biventricular pacing
  • CRT/biventricular pacing may be indicated in DCM patients with evidence of electrical dys-synchrony (e.g., widened QRS complex) and symptomatic heart failure despite optimal medical therapy.
• Heart Transplantation
  • Heart transplantation is considered in end-stage DCM patients with refractory heart failure and poor prognosis despite optimal medical and surgical management. It offers the potential for long-term survival and improvement in quality of life.
• LVADs
  • LVADs may be used while awaiting heart transplantation in patients with advanced heart failure or used in patients unsuitable for heart transplantation.
• Surgical Ventricular Reconstruction (SVR)
  • In select patients with severe left ventricular dilation and dysfunction, SVR involves surgical removal of scarred or non-contractile myocardium, reshaping the left ventricle, and restoring ventricular geometry to improve cardiac function.

Complications

• Heart Failure
  • DCM is characterised by progressive dilation and systolic dysfunction of the ventricles, leading to heart failure symptoms.
• Ventricular Arrhythmias
  • DCM is associated with an increased risk of ventricular arrhythmias, including ventricular tachycardia and ventricular fibrillation, which can lead to syncope, cardiac arrest, or sudden cardiac death.
• Thromboembolism
  • Stasis of blood within dilated ventricles can increase the risk of thrombus formation and subsequent thromboembolic events.