Constrictive Pericarditis vs Restrictive Cardiomyopathy

Definition

Constrictive pericarditis and restrictive cardiomyopathy both produce right-sided heart failure, raised and equalised diastolic pressures across all four chambers, and a dip-and-plateau ventricular tracing. What separates them is where the constraint sits: a rigid pericardium in one, a stiff myocardium in the other. The distinction is pursued because it changes treatment — pericardiectomy can relieve the first, while the second is managed medically and may progress to transplantation — although, as the contradictions below record, that fork is less absolute than it was once taught.

Key Concepts

Aetiology and Context

• Constrictive pericarditis in the modern era follows previous cardiac surgery, mediastinal radiation, viral pericarditis or occurs idiopathically; where tuberculosis is endemic it is the commonest cause. Patients with both radiation and previous surgery frequently have pericardial and myocardial disease together. (sources/hemodynamics-circ-2012, rating: high)
• Restrictive cardiomyopathy is most often amyloidosis in adults, followed by haemochromatosis, sarcoidosis, endomyocardial fibrosis, Fabry disease and the glycogen storage disorders. (sources/rhc-hf-ehj-2025, rating: high)
• The disease-specific detail is on concepts/Constrictive-Pericarditis and entities/RCM; this page covers only what distinguishes them.

Clinical Clues

• Both present with biventricular failure, a raised jugular venous pressure with a Kussmaul sign, peripheral oedema and ascites. Pulsus paradoxus is more prominent in tamponade than in constriction.
• Constriction: an early diastolic knock, and pericardial calcification on imaging — though calcification is absent in many patients.
• Restriction: biatrial enlargement, higher natriuretic peptide levels, and more severe pulmonary hypertension are typical.

Echocardiography and CMR

• Constriction: respirophasic septal shift, an E-wave-predominant mitral inflow varying more than 25% with respiration, a preserved or raised medial mitral annular e′ velocity (>8 cm/s) despite a high E/e′ — the pattern called annulus reversus, in which medial e′ exceeds lateral — a dilated inferior vena cava, and hepatic vein end-diastolic expiratory reversal with a reversal-to-forward velocity ratio of at least 0.8. (sources/pericarditis-acc-2025, rating: very high)
• Restriction: no septal shift, no respiratory variation in inflow, and a markedly reduced e′ (<8 cm/s) reflecting myocardial disease rather than an external constraint.
• Cardiac magnetic resonance adds pericardial thickness and enhancement in constriction — T2-STIR and LGE marking active inflammation in the transient form — and myocardial LGE in a distribution matching the underlying cause in restriction. (sources/pericarditis-acc-2025; sources/rhc-hf-ehj-2025)

The Two Phenotypes Side by Side

(sources/pericarditis-acc-2025, rating: very high; sources/hemodynamics-circ-2012, rating: high)

Shared Haemodynamic Findings

• Both conditions show early rapid filling with a prominent y-descent, dip-and-plateau morphology, equalisation of diastolic pressures (right and left ventricular end-diastolic pressures within about 5 mmHg) and a right atrial to wedge ratio of 0.5 or more. (sources/rhc-hf-ehj-2025, rating: high)
• Absolute pulmonary artery pressures, the ratio of right ventricular end-diastolic to systolic pressure, and the left-right ventricular end-diastolic difference were all used historically, but each has low specificity and none is diagnostic in an individual patient. (sources/hemodynamics-circ-2012)

The Discriminating Finding — Ventricular Interaction

The question is whether ventricular filling is discordant or concordant across the respiratory cycle. (sources/hemodynamics-circ-2012, rating: high)

• In constriction, the rigid pericardium dissociates intrathoracic from intracardiac pressure. Inspiration lowers intrathoracic pressure without transmitting it to the heart, so the gradient driving flow from the pulmonary veins to the left ventricle falls and left ventricular filling falls with it. Because total cardiac volume is fixed within the pericardium, the blood the left ventricle does not take is available to the right — ventricular interaction is enhanced, and right ventricular pressure rises as left ventricular pressure falls. That is discordance.
• In restriction, there is no pericardial constraint and intrathoracic-to-intracardiac coupling is preserved, so both ventricles fill less during inspiration and both pressures fall together. That is concordance.

Measuring the Discordance

• Use high-fidelity manometer-tipped catheters and record simultaneous right and left ventricular tracings during spontaneous respiration. (sources/rhc-hf-ehj-2025, rating: high)
• The systolic area index — the area under the systolic pressure curve, integrated across several respiratory cycles — formalises the comparison: in constriction the right ventricular area increases as the left ventricular area decreases, and this separates constriction from restriction more reliably than the absolute pressures do.

Volume Loading and the Mimics

• Volume loading may be needed to unmask the findings. In a diuretic-treated patient whose diastolic pressures have been normalised, the classic haemodynamics of either condition may not appear until volume is restored. (sources/hemodynamics-circ-2012, rating: high)
• Severe right heart failure is the important mimic. Severe right ventricular systolic or diastolic dysfunction, or severe tricuspid regurgitation, can raise and equalise diastolic pressures and produce a mild degree of respiratory discordance, imitating constriction. Careful examination of how left and right ventricular diastolic pressures change with respiration is what separates the mimic from true constrictive physiology. (sources/hemodynamics-circ-2012)

Constrictive Pericarditis vs Cardiac Tamponade

(sources/hemodynamics-circ-2012, rating: high)

• Effusive-constrictive pericarditis is recognised at the table: after pericardiocentesis the diastolic pressures remain elevated and a prominent y-descent emerges, indicating constriction beneath the effusion. The treatment is pericardiectomy, not further drainage. (sources/hemodynamics-circ-2012)

Management — Where the Distinction Leads

• Constriction: anti-inflammatory therapy for 3–6 months in the transient form, and radical pericardiectomy at an experienced centre in the chronic form. Transient and chronic disease, imaging and surgical technique are on concepts/Constrictive-Pericarditis. (sources/pericarditis-acc-2025, rating: very high)
• Restriction: treat the underlying disease where a specific therapy exists — enzyme replacement or chaperone therapy in Fabry disease, stabilisers in transthyretin amyloidosis — and manage congestion; progression may require transplantation. See entities/RCM and entities/ATTR-Amyloidosis.

Contradictions / Open Questions

• Mixed pericardial and myocardial disease produces intermediate physiology. This is common after radiation or previous surgery: the patient shows neither pure discordance nor pure concordance, and the diagnosis cannot be made from the catheter alone. It requires CMR, the haemodynamics and the clinical context read together. (sources/hemodynamics-circ-2012, rating: high)
• The hepatic vein sign is reported inconsistently. The ACC pericarditis statement places end-diastolic expiratory reversal with a reversal-to-forward ratio of at least 0.8 in constriction, and that is the only assignment the ingested sources support; other accounts give the same sign to restriction, or reverse the inspiratory and expiratory assignment. Until the timing is settled, the sign carries less weight than the respiratory ventricular interaction. (sources/pericarditis-acc-2025, rating: very high)
• "Constriction is curable and restriction is not" is too clean. Transient inflammatory constriction resolves with anti-inflammatory therapy over 3–6 months without surgery, so not every constrictive picture needs pericardiectomy — and the decision to wait is made on imaging evidence of inflammation rather than on haemodynamics. (sources/pericarditis-acc-2025)
• No trial defines the optimal work-up. Whether to proceed to catheterisation, to CMR, or to combine them has never been tested against an outcome; the choice reflects local availability and the degree of diagnostic uncertainty.
• The discordance threshold varies by institutional method. The systolic area index and the various respiratory-discordance ratios are not standardised across laboratories, which is part of why high-fidelity catheters are insisted upon rather than optional. (sources/rhc-hf-ehj-2025, rating: high)

Connections

• concepts/Constrictive-Pericarditis — transient versus chronic disease, imaging and pericardiectomy
• entities/RCM — restrictive cardiomyopathy in depth
• concepts/Cardiac-Tamponade — the other filling obstruction, and the y-descent that separates them
• concepts/Pericarditis — the inflammatory process that precedes constriction
• concepts/RHC-Clinical-Applications — where the ratio and respiratory behaviour are used clinically
• concepts/RHC-Haemodynamic-Interpretation — how simultaneous pressures are measured and read
• entities/Heart-Failure — the syndrome both conditions present with
• entities/ATTR-Amyloidosis — the commonest cause of restrictive cardiomyopathy in adults
• entities/Anderson-Fabry-Disease — an infiltrative cause with specific therapy
• concepts/Pulmonary-Hypertension — the post-capillary picture both can produce

Sources

• sources/hemodynamics-circ-2012
• sources/pericarditis-acc-2025
• sources/rhc-hf-ehj-2025