Cardiovascular · Topic 13 of 48

Dilated, Restrictive & Stress Cardiomyopathy

Cardiovascular · cardiomyopathy

Dilated, Restrictive & Stress Cardiomyopathy

Dilated hearts pump weakly, restrictive hearts fill poorly, and takotsubo stuns the apex after a stressor — find the cause, then treat the physiology.

Key numbers

ICD when LVEF stays ≤ 35% on GDMTLVEF ≤ 35%

DCM is familial in 30–40%familial 30–40%

Takotsubo recovers within days to 3 monthsrecovery ≤ 3 months

01 · What it isDilated: big weak ventricle, no CAD

Dilated cardiomyopathy = LV or biventricular dilation with systolic dysfunction not explained by coronary disease, valve disease or abnormal loading; evaluate for ischemia first, because obstructive coronary disease is common and must be excluded.

02 · What it isRestrictive: stiff small ventricle, big atria

Restrictive cardiomyopathy = a stiff, nondilated ventricle with impaired filling, usually preserved EF, biatrial enlargement and high filling pressures; suspect it in HFpEF with a systemic infiltrative disease such as amyloidosis.

03 · What it isTakotsubo: stress-triggered apical ballooning mimicking MI

Takotsubo (stress) cardiomyopathy is reversible LV dysfunction, classically apical ballooning beyond one coronary territory, after an emotional or physical stressor, mostly in postmenopausal women; it presents like an acute coronary syndrome.

Causes & risk factors

Why it happens

DCM causes: toxins, infection, tachycardia, pregnancy, genesCauses of a dilated heart include alcohol, cocaine and amphetamines, anthracyclines (doxorubicin) and trastuzumab, viral myocarditis, Chagas disease, thyroid disease, thiamine deficiency, persistent tachyarrhythmia, the peripartum period and inherited variants.

Tachycardia-mediated cardiomyopathy is reversiblePersistent tachyarrhythmia (uncontrolled atrial fibrillation), frequent ventricular ectopy or chronic right ventricular pacing can cause LV systolic dysfunction that may reverse once the rate or ectopy is controlled.

DCM is familial in 30–40%About 30–40% of dilated cardiomyopathy is familial (TTN and LMNA are the commonest genes): take a family history of early heart failure or sudden death and consider genetic testing and relative screening.

Presentation

What you'll see

Restrictive: high JVP, rapid y descent, no KussmaulRestrictive cardiomyopathy shows marked JVD with a rapid y descent but no Kussmaul sign, an S3 or S4 (not a pericardial knock), no pulsus paradoxus, crackles, edema and often atrial fibrillation.

Amyloid: thick ventricle with low ECG voltageCardiac amyloidosis is suggested by low QRS voltage despite a thickened ventricle; carpal tunnel syndrome, biceps tendon rupture or spinal stenosis often precede wild-type transthyretin (ATTR) cardiomyopathy by years.

Takotsubo ECG: ST elevation, T inversion, long QTTakotsubo commonly shows precordial ST elevation without reciprocal ST depression, then large diffuse T-wave inversions that may persist for months, and QT prolongation.

Diagnosis & monitoring

Work-up

Takotsubo recovers within days to 3 monthsWall motion in takotsubo usually recovers within days to weeks and is expected to be complete by 3 months; persistent dysfunction at 3 months calls for cardiac MRI to look for another diagnosis.

Management

Orders

Treat the cause plus HFrEF therapy must knowTreat any reversible cause (tachyarrhythmia, alcohol, thyroid, nutritional, inflammatory) and give full HFrEF guideline-directed therapy: beta-blocker, ARNI (or ACE inhibitor/ARB), MRA and SGLT2 inhibitor, with diuretics for congestion.

Suspected takotsubo with ST elevation: urgent angiographyTakotsubo is a diagnosis made after excluding MI: a patient with ST elevation goes for urgent coronary angiography with ventriculography; stable patients without ST elevation may have coronary CT angiography instead.

ICD when LVEF stays ≤ 35% on GDMTA primary-prevention ICD is recommended for symptomatic patients whose LVEF stays ≤ 35% despite chronic guideline-directed therapy; add cardiac resynchronization when the QRS is prolonged, especially with LBBB.

Restrictive: gentle diuresis; vasodilators poorly toleratedPatients with restrictive physiology are preload dependent: diurese cautiously, expect nitrates and RAAS/neprilysin inhibitors to cause hypotension, prefer rhythm control for poorly tolerated AF, and anticoagulate AF, flutter or thrombus.

Exclude AL amyloid before a PYP scanOrder serum and urine protein electrophoresis with immunofixation and serum free light chains to exclude AL amyloidosis; a technetium-99m pyrophosphate scan then diagnoses ATTR cardiomyopathy without biopsy.

ATTR cardiomyopathy: tafamidis or acoramidisTransthyretin stabilizers (tafamidis, acoramidis) lower mortality and hospitalization in ATTR cardiomyopathy; in amyloid heart disease, digoxin, calcium channel blockers, beta-blockers and ACE inhibitors/ARBs are poorly tolerated.

Red flags & don'ts

Avoid harm

Takotsubo shock: avoid catecholamines and inotropes avoidIn takotsubo shock avoid catecholamines (dopamine, dobutamine, norepinephrine), and avoid an intra-aortic balloon pump when there is LVOT obstruction; use temporary mechanical circulatory support for refractory pump failure or LVOT obstruction.

Restrictive cardiomyopathy or constrictive pericarditis?

Commonly confused

Kussmaul sign	Absent
Extra sound	S3 and/or S4
Respiratory variation in ventricular pressures	Minimal
Pericardium	Normal

More detail

Reference

Show 7 reference facts

In dilated cardiomyopathy, anticoagulation is indicated for atrial fibrillation or a documented intracardiac thrombus — not for a low ejection fraction alone.

Large apical ballooning carries LV thrombus risk: anticoagulate (heparin, then oral) until wall motion recovers. Beta-blockers and RAS blockers suit LVEF below 40%, but avoid beta-blockers in pulmonary edema or shock.

Restrictive causes: infiltrative (amyloidosis, sarcoidosis), storage (hemochromatosis, Fabry disease), endomyocardial (hypereosinophilic syndrome, carcinoid, radiation, endomyocardial fibrosis) and idiopathic.

Disease-specific restrictive therapy: immunosuppression for cardiac sarcoidosis, iron chelation for iron overload, enzyme replacement for Fabry disease; a small LV cavity and RV dysfunction often preclude an LVAD, leaving transplant for selected patients.

In peripartum or pregnancy-associated cardiomyopathy, ACE inhibitors, ARBs, ARNI, MRAs, SGLT2 inhibitors and some anticoagulants are potentially teratogenic; anticoagulation may be considered with severe LV dysfunction.

Contemporary 5-year mortality in dilated cardiomyopathy is 20–30% (historically about 50%); deaths are from pump failure and sudden cardiac death.

Constrictive pericarditis — a thickened, sometimes calcified pericardium — gives a Kussmaul sign and a pericardial knock; cardiac CT shows the pericardial thickening, which restrictive cardiomyopathy lacks.

Pearl

Takotsubo looks like a STEMI with clean coronaries; amyloid looks like a thick heart with a quiet ECG.

Sources · Merck Manual Professional — Dilated Cardiomyopathy · Merck Manual Professional — Restrictive Cardiomyopathy · Merck Manual Professional — Amyloidosis · Yalta K et al. Takotsubo Syndrome: An International Expert Consensus Report on Practical Challenges and Specific Conditions (Part 1). Balkan Med J 2024;41:421–441 (PMC11589216) · Ghadri JR et al. International Expert Consensus Document on Takotsubo Syndrome (Part II): Diagnostic Workup, Outcome, and Management. Eur Heart J 2018;39:2047–2062 · Merck Manual Professional — Pericarditis (including constrictive pericarditis) · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).