RESTRICTIVE CARDIOMYOPATHY

✓ Medically ReviewedDISEASEID: MDBT0164🚨 TRIAGE: URGENTICD-10: I42.5

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Definition

CLINICAL DEFINITION

Restrictive cardiomyopathy is a myocardial disorder characterised by restrictive ventricular filling and reduced diastolic volume of either or both ventricles, with normal or near-normal systolic function and wall thickness. It results from increased myocardial stiffness due to infiltrative, storage, or fibrotic processes.

IN PLAIN ENGLISH

A condition where the heart muscle becomes unusually stiff, preventing the heart chambers from relaxing and filling properly with blood between beats. This stiffness leads to fluid backup and symptoms of heart failure, even though the heart's pumping strength remains relatively normal.

COMMON MISCONCEPTION / WHAT IT DOES NOT MEAN

Restrictive cardiomyopathy is NOT primarily a disease of impaired pumping (systolic) function, which defines dilated cardiomyopathy, nor is it caused by external compression of the heart, which defines constrictive pericarditis.

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Word Breakdown

re-

=back, again, or in this context forming 'restrictive' from Latin 'restringere' (to bind back, limit)

cardi-

=heart (from Greek 'kardia')

-myopathy

=disease of muscle (from Greek 'mys' = muscle, 'pathos' = disease)

Literal Meaning: A disease of the heart muscle characterised by restriction

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Abbreviations

RCM=Restrictive Cardiomyopathy — the standard clinical abbreviation

HFpEF=Heart Failure with preserved Ejection Fraction — the typical haemodynamic profile of RCM

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Synonyms & Variants

Infiltrative Cardiomyopathy›Stiff Heart Syndrome›

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Category-Specific Context

As a Disease, restrictive cardiomyopathy represents a specific pathophysiological spectrum of myocardial disorders primarily affecting diastolic function. It is classified alongside dilated, hypertrophic, and arrhythmogenic cardiomyopathies, but is the least common and often secondary to systemic infiltrative or fibrotic diseases.

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Clinical Context & Usage

CLINICAL SETTINGS

Cardiology Outpatient ClinicHeart Failure UnitGeneral Medicine WardIntensive Care Unit

USAGE & DOCUMENTATION NOTES

Clinicians typically document RCM when echocardiography demonstrates severe diastolic dysfunction with biatrial enlargement and preserved ejection fraction, in the absence of significant hypertrophy or pericardial thickening. Notes often specify the suspected underlying aetiology, such as 'cardiac amyloidosis' or 'idiopathic RCM', and track filling pressures and functional class.

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Primary Causes & Pathophysiology

PATHOPHYSIOLOGY

The primary defect in restrictive cardiomyopathy is decreased ventricular compliance due to abnormal myocardial stiffness, caused by interstitial infiltration (e.g., amyloid proteins), storage products (e.g., iron), or endomyocardial fibrosis. This stiffness severely impairs early diastolic relaxation and ventricular filling, leading to a steep rise in ventricular filling pressures for small changes in volume. The elevated left and right ventricular diastolic pressures transmit backward, causing pulmonary venous congestion and systemic venous hypertension. Over time, chronic pressure overload leads to marked biatrial enlargement, while ventricular cavity sizes and systolic function (ejection fraction) typically remain normal or near-normal until late in the disease course.

PRIMARY CAUSES

Amyloidosis (AL and ATTR)

Extracellular deposition of misfolded amyloid fibrils in the myocardial interstitium, causing profound stiffness and restrictive physiology.

Sarcoidosis

Non-caseating granulomatous infiltration of the myocardium leading to fibrosis and restricted filling.

Haemochromatosis

Iron deposition in the myocardium, though it more classically causes dilated cardiomyopathy, it can present with restrictive physiology in earlier or specific stages.

Endomyocardial fibrosis

Fibrotic thickening of the endocardium and inner myocardium, predominantly affecting the apices and inflow tracts, commonly seen in tropical regions.

Radiation-induced heart disease

Mediastinal radiation causes diffuse myocardial and endocardial fibrosis, leading to late-onset restrictive physiology.

Idiopathic

Primary myocardial fibrosis without an identifiable systemic infiltrative or storage disease.

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Drug-Induced Causes

💊 Ergot-derived dopamine agonists (cabergoline, pergolide) ↗

Mechanism: Stimulation of 5-HT2B receptors on cardiac fibroblasts promotes excessive collagen deposition and endomyocardial fibrosis.

→ Discontinue the drug; monitor with serial echocardiography; manage heart failure symptoms.

💊 Chemotherapeutic agents (e.g., cyclophosphamide, anthracyclines) ↗

Mechanism: Direct myocardial toxicity and subsequent fibrotic replacement can lead to restrictive filling patterns.

→ Stop or adjust chemotherapy; standard heart failure management; monitor diastolic function.

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Epidemiology

Prevalence:Rare; accounts for approximately 5% of all cardiomyopathies. Idiopathic RCM has an estimated prevalence of less than 1 in 100,000, though secondary causes like ATTR amyloidosis are increasingly recognised in older populations.

Age Group:Depends heavily on aetiology: idiopathic RCM often presents in childhood or middle age; AL amyloidosis typically affects adults over 50; ATTR amyloidosis predominantly affects older adults (over 65).

Sex Predilection:Male

Geographic Distribution:Endomyocardial fibrosis is highly prevalent in tropical and subtropical regions (e.g., sub-Saharan Africa, South America, India), likely linked to nutritional, infectious, or environmental factors. Infiltrative causes like amyloidosis are globally distributed.

Red Flags & Triage ★

TRIAGE LEVEL

🚨 URGENT

DO NOT MISS — LIFE-THREATENING PRESENTATIONS

New-onset heart failure with preserved ejection fraction and low ECG voltage — raises high suspicion for cardiac amyloidosis, requiring urgent tissue biopsy (e.g., fat pad, bone marrow, or endomyocardial) and specific typing.
Signs of right heart failure out of proportion to left heart disease — consider constrictive pericarditis or right-sided infiltrative disease, necessitating cardiac MRI or catheterisation to differentiate.

URGENT EVALUATION TRIGGERS

Acute decompensated heart failure with severe dyspnoea or hypoxia requiring hospitalisation.
New-onset atrial fibrillation or flutter with rapid ventricular response causing haemodynamic instability.
Syncope or presyncope, which may indicate a malignant arrhythmia or transient high-grade AV block.

Contraindications & Precautions

CONTRAINDICATIONS

Aggressive diuresis must be balanced carefully; over-diuresis can severely reduce preload
leading to a catastrophic drop in cardiac output due to the fixed
stiff ventricular volumes.
Standard heart failure therapies like ACE inhibitors and beta-blockers
while used cautiously
may cause severe hypotension and are not universally beneficial as they are in systolic heart failure.

SPECIAL PRECAUTIONS

Maintain adequate preload to ensure ventricular filling
while carefully managing congestion.
Monitor closely for arrhythmias
particularly atrial fibrillation
which can cause acute haemodynamic collapse due to the loss of atrial kick.
Evaluate for specific treatable causes (e.g.
haemochromatosis
sarcoidosis) before assuming the disease is idiopathic.

Complications

DOWNSTREAM CLINICAL COMPLICATIONS

Heart failure with preserved ejection fraction (HFpEF) — progressive fluid overload and exercise intolerance due to elevated filling pressures.
Atrial fibrillation and thromboembolism — marked biatrial enlargement and stasis predispose to arrhythmias and stroke.
Conduction system disease — infiltration of the AV node and bundle branches can cause heart block requiring pacing.
Pulmonary hypertension — chronic left-sided filling pressures transmit to the pulmonary circulation.

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Confused With (LASA & DDx) ★

LEXICAL (LASA) — SIMILAR NAMES

Constrictive Pericarditis

Shares identical clinical presentation and haemodynamic profile (restrictive filling); distinguishing the two is a classic diagnostic challenge requiring advanced imaging.

Hypertrophic Cardiomyopathy

Both present with diastolic heart failure and preserved ejection fraction, but HCM is characterised by thickened ventricular walls rather than normal wall thickness with stiff myocardium.

CLINICAL DIFFERENTIAL DIAGNOSES (DDx)

Constrictive Pericarditis

Key Distinguishing Feature: Pericardial thickening and calcification on CT/MRI; ventricular interdependence on echo (respiratory variation in inflow velocities); responds to pericardiectomy.

Hypertrophic Cardiomyopathy (HCM)

Key Distinguishing Feature: Asymmetric septal hypertrophy and dynamic left ventricular outflow tract obstruction on echocardiography, unlike the normal wall thickness seen in RCM.

Ischaemic Heart Disease (severe diastolic dysfunction)

Key Distinguishing Feature: History of coronary artery disease, regional wall motion abnormalities, and significant coronary stenosis on angiography.

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Clinical Pearls

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The classic haemodynamic hallmark of RCM on right heart catheterisation is the 'dip-and-plateau' or 'square root' sign in the ventricular pressure tracing, reflecting rapid early diastolic filling followed by an abrupt halt due to the stiff myocardium.

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A striking discordance between ECG voltage and echocardiographic wall thickness is a major red flag for infiltrative disease: low voltage on ECG despite thickened walls on echo strongly suggests cardiac amyloidosis.

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Tissue Doppler Imaging (TDI) is crucial for differentiating RCM from constrictive pericarditis; in RCM, the mitral annular early diastolic velocity (e') is typically reduced (< 8 cm/s), whereas it is often preserved or increased in constrictive pericarditis (annulus reversus).

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Because the stiff ventricles cannot accommodate volume changes, patients with RCM are exquisitely sensitive to both fluid overload (causing pulmonary oedema) and over-diuresis (causing severe low cardiac output states).

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Example Usage & SOAP

CLINICAL SENTENCE

"The patient presented with progressive exertional dyspnoea and peripheral oedema; echocardiography revealed severe biatrial enlargement, normal left ventricular ejection fraction, and a restrictive filling pattern, prompting a workup for infiltrative cardiomyopathy."

IN A SOAP NOTE

S: 68-year-old male presents with worsening lower extremity oedema, abdominal distension, and exertional dyspnoea over the past 3 months. Reports fatigue and early satiety. O: BP 110/70 mmHg, HR 88 bpm irregular. JVP elevated to 10 cm H2O. Bilateral crackles at lung bases. 3+ pitting oedema to the thighs. Ascites present. Echo shows biatrial enlargement, LVEF 60%, severe diastolic dysfunction (grade III), and normal wall thickness. ECG shows low voltage in limb leads and atrial fibrillation. A: Restrictive cardiomyopathy, highly suspicious for cardiac amyloidosis given low ECG voltage and clinical presentation. Decompensated right and left heart failure. P: Admit for diuresis with IV furosemide. Consult Cardiology for cardiac MRI and consideration of endomyocardial biopsy or technetium pyrophosphate (PYP) scan to evaluate for ATTR amyloidosis. Rate control for AF with cautious use of beta-blockers.

DIFFERENTIAL DIAGNOSIS CONTEXT

Differential for restrictive filling pattern on echocardiography: (1) Restrictive Cardiomyopathy (infiltrative/idiopathic) — characterised by abnormal myocardial tissue properties, reduced tissue Doppler e' velocity, and often systemic signs of amyloid or sarcoid; (2) Constrictive Pericarditis — characterised by pericardial thickening, ventricular interdependence (respiratory variation in inflows), and preserved tissue Doppler e' velocity; (3) Severe Hypertrophic Cardiomyopathy — distinguished by marked ventricular hypertrophy and dynamic obstruction; (4) Ischaemic cardiomyopathy with severe diastolic dysfunction — supported by regional wall motion abnormalities and CAD history.

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Prognosis

SHORT-TERM OUTCOME

Highly variable based on aetiology. Idiopathic RCM in children carries a poor prognosis with rapid deterioration without transplantation. In adults with secondary causes, short-term prognosis depends on the reversibility of the underlying infiltrative disease and response to heart failure management.

LONG-TERM PROGNOSIS

Generally poor for idiopathic and amyloid-associated RCM, with median survival often ranging from 1 to 5 years after diagnosis without disease-modifying therapy or transplantation. Endomyocardial fibrosis has a variable course but can be surgically managed in selected cases.

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References & Coding

ICD-10 DIAGNOSTIC CODE

I42.5

LITERATURE CITATIONS & GUIDELINES

[1]Arbustini E, Narula N, Mortara A, et al. Restrictive cardiomyopathy. Nat Rev Dis Primers. 2019;5(1):1-20.

[2]Garcia MJ. Constrictive pericarditis versus restrictive cardiomyopathy. N Engl J Med. 2016;374(13):1254-1264.

[3]McDonagh TA, Metra M, Adamo M, et al. 2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure. Eur Heart J. 2021;42(36):3599-3726.

MEDICAL DISCLAIMER — This content is intended for educational purposes and qualified healthcare professionals only. Always refer to current clinical diagnostic criteria, institutional protocols, and official guidelines. Medobo is not responsible for clinical decisions made based on this content.