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Rapid Review·Cardiovascular

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Cardiomyopathy

T1Must know

Dilated Cardiomyopathy

Focus on

A big, weak heart: EF < 40% with dilated chambers, an S3 and functional MR. The cause list is the exam — alcohol (reversible with abstinence), doxorubicin (irreversible) vs trastuzumab (reversible), viral myocarditis, Chagas, peripartum, tachycardia, wet beriberi, hemochromatosis — and treatment is HFrEF therapy plus removing the cause.

Key takeaways

Cardiomyopathies at a glance

Working up a cardiomyopathy: an ischemic workup, then a transthoracic echo sorts it. Dilated: larger chambers with thin walls and reduced systolic function. Hypertrophic: thick left ventricular walls, normal or small cavity, usually preserved systolic function. Restrictive: diastolic dysfunction with normal or mildly thick walls and normal or slightly reduced systolic function. Stress-induced: akinesis of the apex. All get treatment of the underlying disease and guideline-directed therapy.
What this shows
Working up a cardiomyopathy: an ischemic workup, then a transthoracic echo sorts it. Dilated: larger chambers with thin walls and reduced systolic function. Hypertrophic: thick left ventricular walls, normal or small cavity, usually preserved systolic function. Restrictive: diastolic dysfunction with normal or mildly thick walls and normal or slightly reduced systolic function. Stress-induced: akinesis of the apex. All get treatment of the underlying disease and guideline-directed therapy.

A cardiomyopathy

a disease of the heart muscle, acquired or inherited, that impairs pumping and leads to arrhythmias and heart failure.

Dilated cardiomyopathy (DCM)

dilation with impaired contraction of one or both ventricles, with an ejection fraction (EF) under 40 percent.

Eccentric hypertrophy

sarcomeres are added in series, so the chambers dilate.
The three structural cardiomyopathies beside a normal heart. Hypertrophic: a thicker left ventricular wall with septal predominance. Dilated: ventricular dilation with thin walls and possible atrial dilation. Restrictive: stiff ventricles with dilated atria.
What this shows
The three structural cardiomyopathies beside a normal heart. Hypertrophic: a thicker left ventricular wall with septal predominance. Dilated: ventricular dilation with thin walls and possible atrial dilation. Restrictive: stiff ventricles with dilated atria.
The cardiomyopathies at a glance
TypeMechanismCausesFindings
Dilated (DCM)Systolic dysfunction; eccentric hypertrophy (sarcomeres in series)Idiopathic or familial (TTN gene); ischemic heart disease (most common secondary), hypertension, alcohol, myocarditis, drugs (doxorubicin, zidovudine, cocaine), peripartum, radiation, infections (coxsackievirus, HIV, Chagas), endocrine disease, wet beriberiS3, systolic regurgitant murmur; "balloon" heart on chest radiograph; dilated chambers on echo
Hypertrophic (HCM)Diastolic dysfunction; concentric hypertrophy (sarcomeres in parallel)Hypertension (most common acquired), aortic stenosis, Friedreich ataxia, hypertrophic obstructive cardiomyopathy (HOCM)S4, systolic murmur with mitral regurgitation; left ventricular hypertrophy with septal Q waves; septal hypertrophy, systolic anterior motion of the mitral valve, outflow obstruction on echo
Restrictive (RCM)Diastolic dysfunction without systolic dysfunction; normal or near-normal EFInfiltration (amyloidosis, hemochromatosis, sarcoidosis), scleroderma, Loeffler eosinophilic endocarditis, endomyocardial fibrosis, radiationRight-sided failure predominates (jugular distension, edema, ascites); low voltage or left bundle branch block; rapid early filling on echo; biopsy may show the infiltrate
Stress-induced (Takotsubo)Transient apical ballooning from catecholamine surgeMarked physical or emotional stressLooks like an infarct (chest pain, ST elevation, troponin) with normal coronaries; mid and apical hypokinesis with basal hyperkinesis

Causes of dilated cardiomyopathy

Primary

idiopathic or familial, most often a mutation in the TTN gene (titin).

Ischemic heart disease

the most common secondary cause.
  • It gives focal wall-motion abnormalities, whereas a non-ischemic DCM gives global hypokinesis.

Infection

viral myocarditis (coxsackievirus, HIV), Chagas disease, Lyme disease.

Systemic disease

long-standing poorly controlled hypertension, endocrine disease (thyroid disease, acromegaly, pheochromocytoma), late hemochromatosis, sarcoidosis.

Nutritional

thiamine deficiency (wet beriberi).

Peripartum

the last month of pregnancy or the first five months after delivery (Peripartum Cardiomyopathy).

Toxic

alcohol, chemotherapy, zidovudine, cocaine, radiation.

Tachycardia-mediated

a chronically rapid rate, such as untreated atrial fibrillation with a rapid ventricular response.

Clinical features and diagnosis

Systolic heart failure.

Auscultation

an S3, and a systolic regurgitant murmur from the dilated mitral or tricuspid rings.

Transthoracic echocardiography (TTE)

the gold standard imaging test; shows dilated chambers.
  • The full workup by cause is on the DCM workup.

Chest radiograph

a "balloon" appearance of the heart.

Management

Treat as heart failure with reduced ejection fraction

(Heart Failure) guideline-directed therapy.
  • A beta blocker, an angiotensin-system inhibitor, a mineralocorticoid receptor antagonist and a sodium-glucose cotransporter-2 (SGLT2) inhibitor.

Diuretics

first line for symptoms of volume overload.

Treat the cause

two classic examples.
  • Abstinence is the mainstay for alcoholic cardiomyopathy.
  • Rate or rhythm control is the initial treatment for tachycardia-mediated cardiomyopathy.
A woman treated for breast cancer develops a dilated cardiomyopathy. Which chemotherapy drug makes recovery likely when it is stopped, and which one does not?

Trastuzumab damage is not structural and usually reverses fully when the drug is stopped. Doxorubicin damage is irreversible.

How it's tested

A 45-year-old man drinking a bottle of whiskey daily presents with heart failure and an EF of 20% with global hypokinesis: alcoholic dilated cardiomyopathy — abstinence plus HFrEF drugs; function often recovers.

A breast-cancer patient develops heart failure after her anthracycline course: doxorubicin cardiomyopathy — dose-dependent and usually irreversible; trastuzumab-related dysfunction would be expected to recover.

Persistent AF with ventricular rates of 130–150 for months, now EF 30%: tachycardia-mediated cardiomyopathy — rate control or ablation first; the EF improves.

Immigrant from Brazil with heart failure, an apical LV aneurysm and dysphagia: Chagas cardiomyopathy.

Alcoholic with heart failure, warm extremities and high output: wet beriberi — thiamine before glucose.

Go deeper

Guidelines: 2023 ESC Cardiomyopathy Guideline · 2022 AHA/ACC/HFSA Heart Failure Guideline

Related Step 2 pages: Dilated Cardiomyopathy, Heart Failure, Myocarditis, Peripartum Cardiomyopathy, Atrial Fibrillation, Cardiac Implantable Devices

High-yield images3
Working up a cardiomyopathy: an ischemic workup, then a transthoracic echo sorts it. Dilated: larger chambers with thin walls and reduced systolic function. Hypertrophic: thick left ventricular walls, normal or small cavity, usually preserved systolic function. Restrictive: diastolic dysfunction with normal or mildly thick walls and normal or slightly reduced systolic function. Stress-induced: akinesis of the apex. All get treatment of the underlying disease and guideline-directed therapy.
The three structural cardiomyopathies beside a normal heart. Hypertrophic: a thicker left ventricular wall with septal predominance. Dilated: ventricular dilation with thin walls and possible atrial dilation. Restrictive: stiff ventricles with dilated atria.
Dilated cardiomyopathy workup: symptoms lead to ECG, blood tests, chest film and echo; a dilated ventricle with low ejection fraction is then sorted by history into peripartum, toxin-induced, tachycardia-induced, Chagas, viral myocarditis and ischemic cardiomyopathy, each with its own treatment on top of guideline-directed therapy. Open it full size to read each branch.

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# What is the initial treatment for tachycardia-mediated cardiomyopathy? 

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