Constrictive Pericarditis

Constrictive pericarditis (CP) is a stiff, poorly compliant pericardium restricting diastolic ventricular filling — a unique form of diastolic heart failure from abnormal passive compliance, without myocardial involvement or systolic dysfunction. Recognizing it is genuinely important: pericardiectomy can be curative. Its central diagnostic challenge is distinguishing it from restrictive cardiomyopathy (RCM), a myocardial compliance problem that can look clinically identical — the symptoms, physical findings, and many diagnostic tests frequently fail to separate the two, and occasionally the diagnosis is only established at exploratory thoracotomy. Echocardiography has become the technique of choice for this distinction.

Etiology and Demographics

The cause can’t be established in 30–70% of cases (idiopathic CP). In the United States and other Western countries, cardiac surgery has now overtaken idiopathic/viral disease as the most common identifiable cause — a shift from the historical pattern, in which idiopathic and infectious causes predominated. Other causes include prior pericarditis of any type, mediastinal radiation (constriction typically manifests more than 20 years after treatment — a genuinely long latency), and complications of cardiac surgery. In developing countries and TB-endemic regions, tuberculous, bacterial, fungal, and parasitic pericarditis remain the more common causes. About 0.3% of all cardiac surgery patients go on to develop CP.

Pathophysiology

With the heart encased by a stiff, noncompliant pericardium, the end-diastolic pressure-volume relationship shifts upward and to the left, and diastolic pressures become elevated and equal across all four chambers. Because total pericardial volume is fixed, an increase in one ventricle’s volume forces a decrease in the other’s — pronounced ventricular interdependence.

Early diastolic filling is actually faster than normal, not slower — the restraining effect of the pericardium doesn’t engage until mid-diastole, once the “box” is full, at which point filling ceases abruptly. This produces the classic “dip-and-plateau” or “square root sign” on invasive pressure tracings: a rapid early diastolic pressure fall, followed by a high, flat mid-diastolic plateau.

Respiratory mechanics drive the diagnostic Doppler findings. With inspiration, intrathoracic pressure falls, and this fall is normally transmitted to the pulmonary veins and left atrium — but the thick, rigid pericardium isolates the heart from that pressure change. The pulmonary-venous-to-LA pressure gradient therefore declines with inspiration, reducing transmitral flow and LV filling; the reduced LV volume leaves more of the fixed intrapericardial space available for the RV, which expands to accommodate increased systemic venous return, and the septum shifts leftward. Expiration reverses all of this — LV filling increases, RV filling is limited, and the excess systemic venous return backs up into the IVC and hepatic veins, producing the diastolic flow reversal seen there specifically on the first beat of expiration.

Constriction Is Not Tamponade, Even Though the Physiology Overlaps

Both conditions share fixed cardiac volume, ventricular interdependence with septal shift, and elevated, equalized diastolic pressures — but they diverge in ways worth knowing precisely, not just in general terms. See Cardiac Tamponade for the full tamponade picture; the key contrasts:

Feature	Tamponade	Constriction
Early diastolic filling	Impaired throughout diastole	Rapid, then abruptly ceases mid-diastole
Y descent	Attenuated	Exaggerated
Pulsus paradoxus	Common	Uncommon
Kussmaul’s sign	Absent	Present
Pericardial effusion	Present, often significant	May be absent (thickened pericardium alone)

Kussmaul’s sign — a paradoxical rise in jugular venous pressure with inspiration, rather than the normal fall — reflects the fixed, noncompliant pericardium preventing the usual inspiratory drop in RA pressure. Its presence in constriction and absence in tamponade, paired with the reverse pattern for pulsus paradoxus, is a genuinely useful bedside distinction that’s easy to get backward.

Clinical Findings

• Symptoms: progressive dyspnea, fatigue, weakness, abdominal swelling, peripheral edema, orthopnea.
• Signs: elevated JVP (see Right Atrium Evaluation) with a rapid Y descent; Kussmaul’s sign; a pericardial knock — a sharp, high-pitched early diastolic sound from the abrupt cessation of ventricular filling; hepatomegaly; ascites; a notable absence of murmurs on auscultation.
• Often not clinically considered at presentation — many patients are referred for imaging with heart failure, dyspnea, or peripheral edema as the working diagnosis, with CP only suspected once abnormal septal motion or pericardial thickening is seen.

ECG

Usually nonspecific — normal in many cases, sometimes showing low voltage or nonspecific ST-T changes. Atrial fibrillation is common, reflecting chronic atrial pressure and size elevation. The ECG is not diagnostic on its own.

Chest X-Ray and Cardiac Catheterization

Chest x-ray shows clear lungs with a normal or smaller-than-normal cardiac silhouette; pericardial calcification may be visible. Cardiac catheterization, once the gold standard, shows elevation and equalization of all diastolic pressures with the dip-and-plateau (square root sign) pattern; RV diastolic pressure reaches at least one-third of RV systolic pressure, and pulmonary artery pressure is not markedly elevated. When diastolic pressures are borderline-equalized, a fluid challenge (500 mL IV saline) can help distinguish CP from RCM: in CP the equalization persists, while in RCM the LV diastolic pressure separates and exceeds the RV’s.

Echocardiographic Findings

M-Mode and 2D

• Pericardial thickening appears as parallel-moving, echo-dense layers posterior to the LV epicardium, persisting even at low gain settings — but a normal-appearing pericardium never excludes CP: in one series of surgically confirmed cases, pericardial thickness was normal (≤2 mm) in 18% of patients.
• Diastolic septal bounce/shudder — abrupt posterior septal motion in early diastole, flat motion through mid-diastole, and abrupt anterior motion following atrial contraction — reflects the sequence of rapid early RV filling, equalization at the pressure plateau, and the atrial-contraction filling burst.
• Flat LV posterior wall motion — under 2 mm of posterior excursion from early to late diastole — from impaired diastolic filling.
• IVC and hepatic vein dilation with blunted or absent respiratory collapse, reflecting elevated RA pressure.
• Chamber size: LV wall thickness, dimensions, and systolic function are usually normal; the atria are enlarged from chronically elevated filling pressure — typically moderate enlargement, in contrast to the more severe biatrial enlargement often seen with RCM.
• Premature pulmonic valve opening can occur when RV diastolic pressure approaches or exceeds pulmonary artery diastolic pressure.
• Lateral wall tethering (“annulus reversus” territory, below) — the lateral mitral annulus is restricted in its early-diastolic motion because it’s tethered to the thickened, adherent pericardium, in contrast to the septum, which moves relatively more.

Pulsed Doppler: A Restrictive Transmitral Pattern — Not a Normal One

Transmitral and transtricuspid inflow show a genuinely restrictive pattern — see LV Diastolic Function for the broader restrictive-filling framework this builds on — with a high E velocity, a short deceleration time (under 160 ms), and a small A velocity — giving an elevated E/A ratio, often above 2. A preserved A velocity with a normal E/A ratio would argue against, not support, significant constriction.

• Respiratory variation, with precise timing. Mitral E velocity falls with inspiration — usually, though not always, by 25–40% — with the maximal drop occurring on the first beat of inspiration. Tricuspid E velocity rises with inspiration by a larger margin, often exceeding 40–60%, with the maximal drop occurring on the first beat of expiration — the same moment as the peak hepatic vein atrial reversal. The standard formula for percentage respiratory variation is (expiration velocity − inspiration velocity) ÷ expiration velocity.
• When variation isn’t apparent despite high suspicion, it may be masked by markedly elevated left atrial pressure. Preload reduction — head-up tilt, sitting upright, or nitrates — can unmask the respiratory variation by lowering LA pressure; this maneuver is often less necessary when mitral annular tissue velocity is used instead (below).
• Hepatic vein Doppler shows a prominent a-wave, a deep Y descent, and — the key finding — diastolic flow reversal that increases with expiration, reflecting the dissociation between intrathoracic and intracardiac pressure. This contrasts with SVC flow, which shows little respiratory change in systolic forward velocity. Inspiratory (rather than expiratory) hepatic vein diastolic flow reversal instead suggests restrictive cardiomyopathy — a specific, useful reversal of the expected pattern worth checking for directly.
• Pulmonary venous flow shows a prominent diastolic phase and blunted systolic phase, with the diastolic component increasing specifically with expiration in CP.
• Color M-mode flow propagation velocity is normal or increased in CP — commonly cited thresholds are around 45 cm/s or, in some series, over 100 cm/s — reflecting preserved LV relaxation; it’s reduced in RCM, where the myocardium itself is diseased.
• LV isovolumic relaxation time (IVRT) increases by a mean of roughly 20% with inspiration in CP.

Tissue Doppler: The Two Findings Closest to Pathognomonic

Because the myocardium itself is normal in CP, early diastolic active relaxation is preserved or even enhanced — producing two findings that, together, are unusual enough to be genuinely diagnostic when both are present:

• Annulus reversus. The lateral mitral annular e′ velocity is lower than the septal e′ velocity — the reverse of the normal pattern (where lateral e′ normally exceeds septal e′) — because the lateral annulus is tethered to the thickened, adherent pericardium while the septum moves relatively freely.
• Annulus paradoxus. Despite elevated LV filling pressure, medial/septal e′ is normal or even increased (commonly cited thresholds are 8 cm/s or higher; RCM is generally below 7–8 cm/s), so the E/e′ ratio stays within normal limits or even low (often cited around 8 or below) — the opposite of the usual positive relationship between E/e′ and filling pressure. Medial e′ actually tends to increase further as constriction becomes more severe, which is precisely why E/e′ becomes progressively less, not more, informative about filling pressure as the disease worsens. This combination — high filling pressure with a low or normal E/e′ — is considered close to pathognomonic for CP.
• Confounders that can produce a falsely low e′ despite true CP: regional LV dysfunction and mitral annular calcification. Confounders that can mimic respiratory variation without true constriction: COPD (where transmitral flow isn’t truly restrictive, peak E occurs at end-expiration rather than with inspiration, and SVC flow is exaggerated with inspiration instead), acute pulmonary embolism, RV infarction, and a large pleural effusion.

Strain Imaging

Global longitudinal strain is typically preserved or near-normal in CP, while circumferential strain, LV torsion, and early diastolic untwisting are reduced — the opposite pattern from RCM, where longitudinal strain is reduced but circumferential strain and twisting are relatively preserved. A regional pattern within longitudinal strain can also appear — lateral wall strain reduced relative to preserved septal strain, mirroring the same lateral-tethering mechanism behind annulus reversus.

Constriction vs. Restrictive Cardiomyopathy: A Structured Comparison

No single feature reliably separates the two — the combination, interpreted against clinical context, is what makes the diagnosis.

Feature	Constrictive Pericarditis	Restrictive Cardiomyopathy
Pericardial thickening	Present (may still be absent in ~18% of confirmed cases)	Absent
Respiratory variation in mitral E	Significant (often >25%)	Minimal or absent
Respiratory variation in IVRT	Present, increases with inspiration	Constant, little respiratory change
Septal motion	Abnormal — septal bounce/shudder	Normal
Annulus reversus (lateral e′ vs. septal e′)	Lateral < septal	Lateral > septal (normal pattern)
Septal/medial e′	Normal or increased (often ≥8 cm/s)	Reduced (often under 7–8 cm/s)
E/e′ ratio	Normal or low despite high filling pressure	Elevated, tracks filling pressure normally
Hepatic vein diastolic reversal	Expiratory	Inspiratory (if present)
Pulmonary artery systolic pressure	Mild elevation (roughly 35–40 mmHg)	Moderate-to-severe elevation (often ≥60 mmHg)
Biatrial enlargement	Moderate	Often severe
Longitudinal strain	Preserved	Reduced
Circumferential strain / torsion	Reduced	Preserved
Color M-mode flow propagation	Normal or increased	Reduced
Definitive treatment	Pericardiectomy	Medical management; no surgical cure

Localized (non-uniform) constriction is a genuine variant worth knowing about: when pericardial thickening or calcification is asymmetric, it can constrict some chambers more than others, producing intracavitary pressure gradients — usually affecting the right-sided chambers preferentially — and a less classic overall echo picture.

Effusive-Constrictive Pericarditis: A Distinct Entity

Effusive-constrictive pericarditis (ECP) combines pericardial effusion or tamponade with a constricted visceral pericardium — genuinely distinct from simple effusion with an incidentally thick parietal layer. It’s formally defined by persistence of elevated intracardiac pressure after pericardiocentesis for tamponade: specifically, failure of RA pressure to fall by 50%, or to 10 mmHg or below, once intrapericardial pressure has been normalized by drainage.

• Prevalence varies sharply by clinical context: about 1.3% of all pericarditis, 1.4–3.6% of patients presenting with effusion, and 6.9–7.9% of those presenting with tamponade — rising to 16.1% in one study using routine post-pericardiocentesis Doppler assessment, suggesting the true incidence may be considerably higher than older figures suggest.
• Geography drives cause, just as with classic CP: in TB-endemic regions, tuberculous pericarditis dominates (up to 15% of TB pericarditis cases meet ECP criteria); in Western countries, idiopathic disease predominates, but radiation- and malignancy-related causes are proportionally more common than in classic (non-effusive) CP.
• Three clinical presentations: (1) apparent tamponade that transitions to constrictive physiology once drained; (2) chronic or subacute CP with a partially organized effusion; (3) chronic effusion with right heart failure signs.
• A genuinely useful early echo clue after drainage: a persistently plethoric, noncollapsing IVC immediately after pericardiocentesis — before other constrictive features are fully established — suggests ECP rather than successfully treated simple tamponade.
• Pericardial fluid analysis can help: a higher neutrophil percentage and lower monocyte percentage in the aspirated fluid correlates with constrictive physiology after drainage.
• Calcification is rare in ECP, unlike classic chronic CP, and when present tends to occur in atypical locations.
• Nearly half of ECP is transient, following three phases — acute pericarditis with effusion, then resolution of the effusion with persistent constrictive physiology and heart failure symptoms, then resolution of the constrictive physiology itself — with a mean time to full resolution of 2.7 months (range 12 days to 10 months). Idiopathic and non-calcific tuberculous ECP are more likely to follow this transient course.
• Epicardiectomy — removal of the visceral, not just the parietal, pericardium — is the surgical procedure of choice when surgery is needed, and reported early surgical mortality (15–30%) is notably higher than for classic CP (5–8%), underscoring why adequate time for medical therapy matters before committing to surgery.

Additional Imaging and Diagnostic Confirmation

• CT shows pericardial thickening (commonly cited thresholds are over 3–4 mm) and calcification; indirect signs include tubular ventricular deformity, IVC or hepatic vein dilation, ascites, and pleural effusion.
• Cardiac MRI can also assess pericardial thickening, and — via late gadolinium enhancement — can identify active pericardial inflammation, which is clinically important because inflamed, LGE-positive constriction can genuinely improve with anti-inflammatory therapy (including corticosteroids) rather than requiring surgery. Cine and tagged CMR can also directly show septal bounce, abrupt cessation of diastolic filling, ventricular interdependence, and pericardial-myocardial tethering from adhesions.
• A lack of pericardial thickening or calcification on CT/CMR does not rule out CP, and their presence does not guarantee it — imaging findings must still be interpreted alongside the hemodynamic and Doppler picture.
• TEE is more accurate than TTE specifically for measuring pericardial thickness, correlating well with CT.
• Right and left heart catheterization remains useful when noninvasive findings are equivocal.

How to Diagnose It: A Practical Sequence

1. Maintain a high index of suspicion in unexplained right heart failure, ascites, or peripheral edema, particularly with a history of cardiac surgery, mediastinal radiation, prior pericarditis, or TB exposure — many cases are referred without CP already being considered.
2. Look for pericardial thickening and echo-bright, parallel-moving pericardial layers, but don’t rule out CP if the pericardium looks normal.
3. Look for septal bounce/shudder and flat LV posterior wall diastolic motion on 2D and M-mode.
4. Record transmitral and transtricuspid inflow with a respirometer trace, confirming a restrictive pattern (high E, short deceleration time, low A, elevated E/A) and checking the precise respiratory timing — peak mitral E drop on the first inspiratory beat, peak tricuspid E drop on the first expiratory beat.
5. If respiratory variation isn’t apparent despite suspicion, try preload reduction (head-up tilt, sitting, or nitrates) before concluding it’s absent.
6. Record hepatic vein Doppler, confirming expiratory (not inspiratory) diastolic flow reversal.
7. Record mitral annular tissue Doppler at both the septal and lateral annulus, checking for annulus reversus (lateral e′ < septal e′) and annulus paradoxus (normal/low E/e′ despite the restrictive transmitral pattern).
8. Add strain imaging if available — preserved longitudinal strain with reduced circumferential strain/torsion supports CP over RCM.
9. Actively exclude confounders: atrial fibrillation and markedly elevated filling pressure can blunt respiratory variation; COPD, pulmonary embolism, RV infarction, and large pleural effusions can each produce some respiratory Doppler variation without true constriction. Also screen for alternative or coexisting explanations for the clinical picture — RV dysfunction and severe tricuspid regurgitation can each mimic or complicate the presentation.
10. Escalate to CT or CMR when findings are equivocal, to assess pericardial thickness, calcification, and — with CMR specifically — active inflammation via late gadolinium enhancement.
11. Consider cardiac catheterization, including a fluid challenge if diastolic pressures are borderline- equalized, when noninvasive testing remains inconclusive.
12. If tamponade has recently been drained and constrictive features persist or emerge, consider effusive-constrictive pericarditis specifically, and reassess the IVC and hepatic veins even after the effusion itself is gone.

Treatment and the Current Management Framework

• A trial of anti-inflammatory therapy before surgery is now explicitly recommended for newly diagnosed CP. The 2025 ESC guideline recommends 3 to 6 months of anti-inflammatory therapy before referral for pericardiectomy in newly diagnosed, non-calcific cases — since roughly 10% of pericarditis cases develop transient constrictive physiology, and more than half of transient cases resolve with anti-inflammatory treatment. Biomarkers (elevated CRP) and multimodality imaging, particularly CMR for pericardial inflammation, help decide who’s a reasonable candidate for this trial.
• Formal risk stratification now guides management: low risk (clinical remission and normalized imaging after therapy) is managed with outpatient follow-up; intermediate risk (improved but incomplete resolution) gets close follow-up within a month; high risk (persistent symptoms and persistent imaging signs of constriction) proceeds to pericardiectomy.
• It’s possible to have constrictive physiology on imaging without heart failure symptoms — septal bounce, respiratory septal shift, and Doppler constriction features can all be present without clinical decompensation, and this distinction matters for how aggressively to intervene.
• Pericardiectomy remains the definitive treatment for chronic, symptomatic CP that doesn’t respond to medical therapy, with a perioperative mortality of roughly 5–8%. Predictors of worse long-term outcome include age over 55, a history of prior radiation, advanced (NYHA class IV) preoperative status, and incomplete pericardiectomy. Survivors show marked functional improvement, though late survival remains somewhat inferior to age- and sex-matched controls.

Clinical Importance

Constrictive pericarditis is the pericardial disease most likely to be curable and most likely to be missed — curable because pericardiectomy (or, increasingly, medical therapy for the transient, inflammatory form) can genuinely reverse it, and missed because its physical findings, ECG, and even many individual echo signs overlap so heavily with restrictive cardiomyopathy and ordinary heart failure. The findings that actually separate it — annulus reversus, annulus paradoxus, the precise respiratory timing of transmitral and hepatic vein flow, and expiratory (not inspiratory) hepatic vein reversal — reward exactly the kind of careful, deliberate technique this diagnosis has always demanded.