Constrictive Pericarditis

Table of Contents

  1. Overview
  2. Causes and Epidemiology
  3. Pathophysiology
  4. Clinical Presentation
  5. Hemodynamics
  6. Diagnosis
  7. Differentiation from Restrictive Cardiomyopathy
  8. Treatment
  9. Radiation-Associated Constrictive Pericarditis
  10. Prognosis
  11. Research Papers
  12. Connections
  13. Featured Videos

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1. Overview

Constrictive pericarditis (CP) is a chronic condition in which the pericardium — the fibrous sac surrounding the heart — becomes thickened, fibrotic, and often calcified, losing its normal compliance and imposing a rigid external constraint on all four cardiac chambers. Unlike cardiac tamponade, which causes compression through accumulated fluid, CP is a solid structural restriction: the pericardium itself has been replaced by an inelastic scar that physically prevents normal diastolic expansion of the ventricles.

The defining hemodynamic consequence is equal restriction of diastolic filling in all four chambers. Because the rigid pericardial shell limits total cardiac volume, ventricular filling pressures equilibrate — right atrial pressure, left atrial pressure, and both ventricular end-diastolic pressures converge to the same elevated value. This diastolic equalization is the hemodynamic fingerprint of CP and distinguishes it from most other cardiac conditions.

A critically important clinical point: CP is one of the few forms of heart failure that is potentially surgically curable. Pericardiectomy — surgical removal of the fibrotic pericardium — can restore normal cardiac filling and dramatically improve symptoms in the majority of patients. This makes accurate diagnosis and distinction from restrictive cardiomyopathy (which carries a very different prognosis and has no surgical cure) one of the highest-stakes differentials in clinical cardiology.

CP may present insidiously over months to years, often mimicking liver disease (from hepatic congestion and ascites) or nephrotic syndrome, leading to delayed diagnosis. Recognizing the clinical syndrome early — particularly the combination of right heart failure, Kussmaul's sign, a pericardial knock on auscultation, and a history of pericardial injury — is essential for timely referral to an experienced center.

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2. Causes and Epidemiology

Constrictive pericarditis results from any process that triggers pericardial inflammation followed by fibrosis and scarring. The relative importance of individual etiologies varies markedly by geographic region and socioeconomic context.

Radiation Therapy

In the developed world, prior chest radiation therapy has become the most common identifiable cause of CP. Mediastinal radiation for breast cancer, Hodgkin lymphoma, and lung cancer delivers doses to the pericardium that trigger an initial radiation pericarditis, followed by fibrosis that evolves over a characteristically long latency period of 10–20 years after treatment. Radiation-associated CP is among the most severe forms — the pericardium is densely fibrotic and may be inseparably fused to the underlying myocardium and epicardium. The myocardium itself is frequently damaged by radiation (radiation cardiomyopathy, coronary artery disease), making surgical intervention substantially more complex and increasing operative risk.

Idiopathic and Post-Viral

In many patients in developed countries, no specific cause can be identified — these cases are classified as idiopathic. Many are presumed to represent sequelae of unrecognized or subclinical viral pericarditis (most commonly coxsackievirus B, echovirus, and adenovirus). Idiopathic CP often responds better to pericardiectomy than radiation-associated forms, with superior long-term outcomes.

Cardiac Surgery

Post-cardiac surgery CP — following coronary artery bypass grafting (CABG), valve repair or replacement, or other cardiac procedures — is an increasingly recognized cause. Post-pericardiotomy syndrome (an immune-mediated pericarditis occurring weeks to months after cardiac surgery) may evolve into CP. The incidence of CP after cardiac surgery is estimated at 0.2–0.3%, but given the large volume of cardiac operations performed annually, it constitutes a meaningful absolute number.

Tuberculosis

TB pericarditis remains the most common cause of CP globally, particularly in sub-Saharan Africa, Southeast Asia, and other regions with high TB prevalence. Tuberculous pericarditis follows a characteristic course: initial exudative pericarditis → organized effusive-constrictive phase → progressive pericardial fibrosis and calcification. Heavy pericardial calcification visible on chest X-ray or CT in the correct geographic and demographic context should prompt TB evaluation. Antituberculous therapy can prevent progression to CP if given early, but established CP requires pericardiectomy.

Other Causes

Epidemiology: CP is uncommon, with an estimated prevalence of approximately 1 in 10,000 in general populations. It represents a small fraction of heart failure cases but is disproportionately important because it is surgically curable. CP affects men slightly more often than women. It can occur at any age; radiation-associated CP presents later (latency 10–20 years after treatment) and TB-associated CP tends to affect younger patients in endemic regions.

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3. Pathophysiology

The fundamental pathophysiological derangement in constrictive pericarditis is loss of pericardial compliance. The normal pericardium is a relatively inelastic fibrous sac that passively accommodates cardiac motion without imposing significant constraint under normal filling volumes. In CP, progressive fibrosis and calcification eliminate this accommodation, converting the pericardium into a rigid shell that limits total cardiac volume.

Equal Restriction of All Four Chambers

Because the rigid pericardium constrains the total cardiac volume, the filling of one chamber can only occur at the expense of another. This fixed total volume constraint means that all four chambers share the same absolute filling limit — producing the characteristic diastolic pressure equalization: right atrial pressure = left atrial pressure = right ventricular end-diastolic pressure (RVEDP) = left ventricular end-diastolic pressure (LVEDP) = pulmonary artery diastolic pressure (PAD), all within 5 mmHg of each other. This equalization is pathognomonic and forms the basis for the diagnostic hemodynamic criterion at cardiac catheterization.

Ventricular Interdependence and Septal Bounce

A second key consequence of the rigid pericardial shell is exaggerated ventricular interdependence. Normally, inspiration increases right ventricular (RV) filling and slightly decreases left ventricular (LV) filling — the interventricular septum shifts slightly leftward with inspiration. In CP, the rigid pericardium amplifies this interdependence. Because the total cardiac volume cannot change, increased RV filling during inspiration must displace the interventricular septum sharply leftward, producing the characteristic septal bounce visible on echocardiography — an abnormal, exaggerated septal motion with respiration. This can also be visualized on M-mode echocardiography as abnormal posterior wall motion.

The respiratory variation in ventricular filling also accounts for the exaggerated variation in transvalvular Doppler flow velocities: mitral E velocity decreases by >25% with inspiration (as LV filling is impaired by rightward septal shift) and tricuspid E velocity increases with inspiration. This reciprocal respiratory variation >25% across the atrioventricular valves is a key echocardiographic criterion for CP.

Kussmaul's Sign — Mechanism and Contrast with Tamponade

Kussmaul's sign (jugular venous pressure rises or fails to fall with inspiration) is present in CP. Normally, inspiration increases venous return to the right heart and JVP falls as the RV accommodates the increased flow. In CP, the rigid pericardial shell cannot accommodate the increased RV volume during inspiration — the increased venous return is transmitted back to the jugular veins, causing JVP to rise or remain elevated. Kussmaul's sign is a physical examination hallmark of CP.

In cardiac tamponade, Kussmaul's sign is characteristically absent. Instead, tamponade presents with pulsus paradoxus — an exaggerated fall in systolic blood pressure (>10 mmHg) with inspiration, caused by increased RV filling during inspiration shifting the septum leftward and reducing LV stroke volume. Tamponade also features muffled heart sounds, elevated JVP, and hypotension (Beck's triad). The distinction between tamponade (fluid = compressible, pulsus paradoxus present, urgent pericardiocentesis) and CP (solid fibrosis = rigid shell, Kussmaul's sign present, surgical pericardiectomy) is fundamental.

Transient (Inflammatory) vs. Permanent (Fibrotic) CP

An important clinical distinction: early in the evolution of pericardial disease — particularly post-viral or post-surgical pericarditis — an effusive-constrictive or transient constrictive physiology may develop during the active inflammatory phase. This early constriction is mediated by pericardial inflammation and edema rather than permanent fibrosis. In this phase, anti-inflammatory therapy (NSAIDs + colchicine ± corticosteroids) can resolve the constriction over weeks to months without surgery. Identifying the transient, inflammatory phase is critical — these patients should receive a trial of anti-inflammatory therapy before surgical referral. Gadolinium enhancement of the pericardium on cardiac MRI (suggesting active inflammation rather than inert fibrosis) is the key imaging discriminator.

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4. Clinical Presentation

The clinical presentation of constrictive pericarditis is dominated by the consequences of chronically elevated venous pressures — primarily right heart failure — in a patient who may have surprisingly preserved biventricular systolic function. The insidious, slowly progressive course frequently leads to diagnostic delay, with patients sometimes labeled as having idiopathic liver disease, nephrotic syndrome, or cryptogenic ascites before CP is identified.

Symptoms

Signs

Contrast with Cardiac Tamponade

The bedside distinction between CP and tamponade is of immediate clinical importance, since tamponade requires urgent pericardiocentesis while CP requires planned pericardiectomy. Key differentiators:

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5. Hemodynamics

Cardiac catheterization provides the definitive hemodynamic characterization of constrictive pericarditis. While echocardiography and cardiac MRI can strongly suggest the diagnosis non-invasively, right heart catheterization — and often simultaneous right and left heart catheterization — remains the gold standard for confirming constrictive physiology and differentiating CP from restrictive cardiomyopathy.

The Square Root Sign (Dip-and-Plateau)

The most characteristic hemodynamic waveform in CP is the square root sign on ventricular pressure tracings. During diastole, ventricular pressure demonstrates:

  1. Rapid early diastolic pressure drop: as the atrioventricular valve opens, blood rushes rapidly into the ventricle (the "dip") — early diastolic filling is actually accelerated in CP because of the steep atrio-ventricular pressure gradient built up by elevated atrial pressures
  2. Abrupt mid-diastolic plateau: filling abruptly halts when the expanding ventricle meets the rigid pericardial wall (the "plateau") — no further filling occurs through mid and late diastole

On the ventricular pressure trace, this creates a waveform resembling a square root symbol (√), also called the "dip-and-plateau" pattern. On the atrial pressure tracing, the rapid early diastolic filling is reflected as a prominent, steep Y descent (rapid fall in atrial pressure as blood empties into the ventricle during early diastole).

Diastolic Pressure Equalization

The pathognomonic hemodynamic finding in CP is equalization of all diastolic filling pressures within 5 mmHg:

Respiratory Discordance of RV and LV Pressures

A critical differentiating hemodynamic feature between CP and restrictive cardiomyopathy (RCM) is the respiratory behavior of simultaneous RV and LV systolic pressures. In CP, the fixed total pericardial volume means that as inspiration increases RV filling and RV systolic pressure rises, LV filling simultaneously decreases and LV systolic pressure falls — the two ventricular pressure peaks move in opposite directions with respiration (discordance). In RCM, both pressures rise and fall together with respiration (concordance), because there is no fixed external constraint. This RV-LV pressure discordance on respiratory variation, measured on simultaneous high-fidelity pressure tracings during right and left heart catheterization, is the most definitive invasive test for distinguishing CP from RCM when the diagnosis remains uncertain after non-invasive testing.

Pulmonary Artery Pressure

Pulmonary artery systolic pressure in CP is typically modestly elevated (30–45 mmHg), reflecting the chronically elevated left atrial pressure. Severely elevated pulmonary hypertension (>60 mmHg) is unusual in CP and should prompt consideration of an alternative or concurrent diagnosis. By contrast, in severe RCM, pulmonary hypertension may be more prominent. The relatively modest pulmonary hypertension in CP (proportionate to the elevated PCWP) is consistent with passive pulmonary venous hypertension rather than reactive pulmonary arterial disease.

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6. Diagnosis

The diagnosis of CP integrates clinical history, physical examination, imaging, and hemodynamics. No single test is definitively diagnostic in isolation; the diagnosis rests on the convergence of multiple supportive findings.

Chest X-Ray

Pericardial calcification on plain chest X-ray — appearing as a curvilinear opacity following the cardiac contour, best seen on the lateral view — is highly specific for CP when present. However, it is absent in many cases (particularly idiopathic and post-surgical CP) and its absence does not exclude the diagnosis. Pleural effusions and signs of pulmonary venous congestion may also be present.

CT of the Chest

CT is the most sensitive imaging modality for detecting pericardial calcification and thickening. Key CT findings in CP:

Cardiac MRI

Cardiac MRI (CMR) is the most informative non-invasive test for evaluating pericardial disease and myocardial structure. CMR findings in CP:

Echocardiography

Echocardiography is the first-line imaging modality and provides multiple complementary signs. No single echo finding is pathognomonic, but the combination is highly diagnostic:

Right Heart Catheterization

When non-invasive testing is inconclusive or when differentiation from RCM is critical, right heart catheterization (with simultaneous left heart catheterization if needed) provides definitive hemodynamic characterization as detailed in the Hemodynamics section. Provocative testing (rapid saline infusion to unmask constrictive physiology that is not apparent at rest) may be required in early or partially treated CP where resting pressures are only mildly elevated.

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7. Differentiation from Restrictive Cardiomyopathy

The differential diagnosis of CP versus restrictive cardiomyopathy (RCM) is one of the most clinically important distinctions in cardiology. Both conditions present with diastolic heart failure, elevated filling pressures, and diastolic pressure equalization on cardiac catheterization. The critical difference: CP is potentially surgically curable by pericardiectomy; RCM has no surgical cure and carries a worse prognosis. Misclassifying CP as RCM denies the patient a curative operation; misclassifying RCM as CP exposes the patient to high-risk surgery with no benefit.

Clinical and Imaging Features Favoring CP

Clinical and Imaging Features Favoring RCM

Hemodynamic Differentiation at Catheterization

When imaging is inconclusive, simultaneous high-fidelity RV and LV pressure recording during catheterization provides the most definitive differentiation:

Role of Cardiac MRI

CMR is the most useful single non-invasive test for differentiating CP from RCM. Pericardial thickening, myocardial tethering, and gadolinium pericardial enhancement all favor CP. The LGE pattern in RCM is characteristically myocardial (global subendocardial in amyloid, patchy mid-wall in sarcoid or other infiltrative diseases) rather than pericardial. CMR also characterizes myocardial tissue properties (T1 mapping for amyloid, T2 mapping for edema, ECV for fibrosis quantification) that may establish the cause of RCM.

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8. Treatment

Treatment of CP is fundamentally divided based on whether the constriction is transient (inflammatory, potentially reversible) or permanent (established fibrosis/calcification, requiring surgery).

Transient Constrictive Pericarditis — Anti-Inflammatory Trial

In patients with recent-onset CP (weeks to a few months post-viral pericarditis, post-cardiac surgery, or post-pericardiocentesis) where gadolinium enhancement of the pericardium on CMR suggests active inflammation, a structured anti-inflammatory trial of 3 months should be attempted before surgical referral:

Permanent Constrictive Pericarditis — Pericardiectomy

Pericardiectomy (surgical decortication — removal of the fibrotic/calcified pericardium) is the definitive and standard treatment for established CP that has failed or is not a candidate for anti-inflammatory therapy.

Medical Management (Palliative or Bridge)

Medical therapy does not change the natural history of established CP but provides symptom relief:

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9. Radiation-Associated Constrictive Pericarditis

Radiation-associated CP deserves special emphasis as the most severe and surgically challenging form of the disease. As cancer survival improves — particularly for breast cancer, Hodgkin lymphoma, and lung cancer — the long-term cardiac complications of mediastinal and thoracic radiation therapy are becoming increasingly prevalent.

Pathogenesis and Latency

Ionizing radiation damages vascular endothelium, myocardial cells, and pericardial mesothelium through direct DNA damage, reactive oxygen species generation, and downstream inflammatory cascades. Radiation pericarditis may be acute (occurring during or shortly after radiation, usually asymptomatic) or delayed. The characteristic latency for clinically significant constrictive pericarditis is 10–20 years after chest radiation, though cases have been reported as early as 5 years and as late as 30+ years post-treatment. The latency reflects the slow evolution of fibrosis over years following the initial radiation-induced injury.

Pathological Severity

Radiation-associated CP differs qualitatively from idiopathic or post-viral CP in pathological severity:

Surgical Outcomes

Pericardiectomy for radiation-associated CP carries substantially higher operative risk than for other etiologies:

Prevention

Modern radiation oncology techniques have dramatically reduced the cardiac dose delivered during cancer treatment. Intensity-modulated radiation therapy (IMRT), proton beam therapy, deep-inspiration breath-hold techniques (for left breast cancer), and cardiac-sparing radiation planning aim to minimize pericardial dose. These advances are expected to reduce the future incidence of radiation-associated CP, though the 10–20 year latency means that cases from older treatment regimens will continue to present for years to come.

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10. Prognosis

The prognosis of constrictive pericarditis is highly dependent on etiology, timeliness of diagnosis, and access to surgical expertise.

Without Treatment

Untreated established CP follows a course of progressive right and eventually biventricular heart failure. Chronically elevated venous pressures lead to cardiac cirrhosis (hepatic fibrosis from persistent congestion), protein-losing enteropathy, nutritional depletion, renal venous congestion, and cachexia. Without pericardiectomy, median survival from the onset of significant symptoms is typically less than 5 years, with progressive functional decline dominating the clinical course.

After Pericardiectomy

Pericardiectomy dramatically improves outcomes for most patients with non-radiation CP:

Predictors of Poor Outcomes After Pericardiectomy

Recurrence

Recurrent CP after complete pericardiectomy is uncommon, occurring in fewer than 5% of cases. Incomplete resection, leaving residual pericardial tissue (particularly at the posterior left ventricle and great vessels), is the primary cause of persistent or recurrent constrictive physiology. When recurrence does occur, re-do pericardiectomy carries substantially higher risk than the initial operation due to pericardial and epicardial adhesions, and outcomes are more variable.

Transient CP

Patients with inflammatory (transient) CP who respond to anti-inflammatory therapy have an excellent prognosis. Complete resolution of constrictive physiology occurs in the majority, with no requirement for pericardiectomy. Long-term follow-up is warranted, as some patients may develop recurrent episodes or ultimately progress to permanent CP if anti-inflammatory therapy is inadequate.

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11. Research Papers

  1. Imazio M et al. Constrictive pericarditis. J Am Coll Cardiol. 2015;75(16):1935-1950.
  2. Cho YH et al. Pericardiectomy for constrictive pericarditis: etiology and outcomes. Heart. 2015;101(20):1616-1621.
  3. Bertog SC et al. Constrictive pericarditis: etiology and cause-specific survival after pericardiectomy. J Am Coll Cardiol. 2004;43(8):1445-1452.
  4. Nishimura RA. Constrictive pericarditis in the modern era: a diagnostic dilemma. Heart. 2001;86(6):619-623.
  5. Feng D et al. Intrapericardial calcification on chest computed tomography: clinical correlates of 125 cases. J Am Coll Cardiol. 2011;58(21):2171-2178.
  6. Hatle LK et al. Differentiation of constrictive pericarditis and restrictive cardiomyopathy by Doppler echocardiography. Circulation. 1989;79(2):357-370.
  7. Syed FF et al. Diagnosis of constrictive pericarditis. Heart. 2012;98(5):334-342.
  8. Talreja DR et al. Constrictive pericarditis in 26 patients with histologically normal pericardial thickness. Circulation. 2003;108(15):1852-1857.
  9. Myers RB et al. Cardiovascular complications of mediastinal radiotherapy: pathogenesis, diagnosis, and management. Best Pract Res Clin Haematol. 2008;21(1):163-176.
  10. Klein AL et al. American Society of Echocardiography clinical recommendations for multimodality cardiovascular imaging of patients with pericardial disease. J Am Soc Echocardiogr. 2013;26(9):965-1012.
  11. Imazio M et al. Indications for pericardiectomy: pathophysiology, clinical presentation, and diagnostic workup. Int J Cardiol. 2015;191:138-141.
  12. Garcia MJ. Constrictive pericarditis versus restrictive cardiomyopathy? J Am Coll Cardiol. 2016;67(17):2061-2076.

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Connections

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