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Cardiomyopathy Overview: Dilated, Hypertrophic, Restrictive

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Heart Failure & CardiomyopathyIntermediateIn progressOne-page PDF

Compare DCM, HCM, and restrictive cardiomyopathy with causes, echo clues, workup, treatment, and referral triggers.

Combines dilated, hypertrophic, and restrictive cardiomyopathy on one comparison sheet.

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Pending initial clinical review

Disclaimer: Educational reference only. Not a substitute for clinician judgment, local protocols, or current guideline review.

Draft content pending the site owner’s clinical review. Verify against the sources above and local protocol before clinical use.

Diseases of heart muscle. Three classic phenotypes: dilated (DCM), hypertrophic (HCM), and restrictive (RCM).
Phenotype guides workup, treatment, family screening, and sudden-death risk assessment.

Feature	DCM	HCM	RCM
Ejection fraction	Reduced	Usually preserved	Preserved / near-normal
Hallmark	Dilated LV, systolic dysfunction	Asymmetric septal hypertrophy, SAM, LVOT obstruction	Stiff ventricle, impaired filling, biatrial enlargement
Common causes	Idiopathic, ischemic, genetic, alcohol, tachycardia-mediated, peripartum, myocarditis	Sarcomere gene mutations (autosomal dominant)	Amyloid, sarcoid, hemochromatosis, radiation, fibrosis
Key risks	HF, arrhythmia, SCD	SCD (esp. young/athletes), AF, HF	HF, AF, conduction disease

Echocardiography is first-line; cardiac MRI adds tissue characterization (fibrosis, infiltration).
HCM: murmur intensifies with Valsalva/standing (less preload); screen for LVOT obstruction.
RCM: look for infiltrative disease — suspect amyloid with LVH + low ECG voltage + neuropathy → PYP scan and serum/urine free light chains.
Genetic testing and first-degree relative screening for HCM and many DCM cases.

Avoid dehydration and arterial vasodilators if obstructive
Beta-blocker or verapamil; disopyramide or a cardiac myosin inhibitor (e.g., mavacamten) for obstructive symptoms
SCD risk stratification for ICD; septal reduction (myectomy/alcohol ablation) for refractory obstruction; activity counseling

HCM with syncope, exertional symptoms, or a family history of sudden death → urgent risk stratification.
New high-grade conduction disease with HF → consider infiltrative disease (sarcoid/amyloid).

HCM is a leading cause of sudden cardiac death in young athletes.
A preserved EF does not mean a normal heart — HCM and RCM both cause symptoms with normal EF.
Suspect cardiac amyloidosis in "HFpEF" with LVH, low voltage, bilateral carpal tunnel, or neuropathy.

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