Pericardial diseases include pericarditis, constriction, and congenital or traumatic pericardial lesions. Although the etiologies for pericarditis are numerous (Table 18-1), the initiating factors for inflammation and effusion are shared and any of these factors, if chronic, can eventually cause pericardial constriction.4,6
There are three stages to pericardial inflammation: (1) vasodilation leading to transudation of a protein-poor, cell-free fluid; (2) increased vascular permeability allowing protein (fibrin) to leak; and (3) inflammatory cell migration. The presenting complaint is usually substernal chest pain, radiating to the left scapular ridge, pleuritic, and positional (often relieved leaning forward). As an effusion develops, symptoms from compression of adjacent structures (trachea, esophagus, phrenic nerve, and recurrent laryngeal nerve) include dyspnea, cough, dysphagia, singultus, and dysphonia.3,5,6
Patients with pericarditis have systemic evidence of inflammation on blood testing, including a leukocytosis and elevated C-reactive protein level and erythrocyte sedimentation rate. Troponin levels are elevated in 35–50% of pericarditis cases (creatine kinase-MB fraction less often) due to epicardial inflammation, and typically return to baseline within 1–2 weeks. The magnitude of the troponin rise appears to correlate with the height of the ST-segment elevation but does not necessarily predict an adverse outcome. Serum troponin levels remaining elevated for more than 2 weeks suggest an associated myocarditis, which does predict a worse prognosis.6,7 The initial workup and management for any patient with presumed pericarditis should be: (1) an evaluation for possible underlying or causative conditions; (2) echocardiography to determine if there is an effusion (and, if so, its size), tamponade, or other structural abnormalities; (3) alleviation of symptoms with anti-inflammatory medications; and (4) treatment for a specific condition if identified.4,5,7
Viral agents are the most common cause of pericarditis, as documented by rising antibody titers, but also represent the majority of cases thought to be idiopathic (Table 18-2). Enteroviridae (Coxsackie B), Adenoviridae, Echoviridae, and Retroviridae are usually responsible, and pericardial involvement typically occurs 1–3 weeks following a URI or GI infection, although rarely pericarditis can occur with the primary infection. Viral pericarditis is typically “dry”—without a pericardial effusion—with a rub present, or may develop a small effusion that is asymptomatic and resolves spontaneously.5,7,8 Although atrial arrhythmias can be seen, mostly with constrictive disease, patients with uncomplicated pericarditis predominantly remain in sinus rhythm and have no significant arrhythmias. When arrhythmias occur, underlying conductive disease or an associated myocarditis is usually responsible and should be sought. The classic example is Lyme pericarditis, which is really a pancarditis that can cause a bundle branch or A-V nodal block.3,9
Table 18-2. Microbiology of Infectious Pericarditis |Favorite Table|Download (.pdf)
Table 18-2. Microbiology of Infectious Pericarditis
- Coxsackievirus A and B
- Epstein–Barr virus
- Paramyxovirus (mumps)
- Gram-negative bacilli
- Haemophilus influenzae
- Bordetella pertussis
- Francisella tularensis
- Toxoplasma gondii
- Trypanosoma cruzi
- Filarioidea (microfilaria)
- Avium-intracellulare complex
In the pre-antibiotic era, purulent pericarditis resulted in a nearly 100% mortality rate. Unfortunately today it still carries a high mortality rate (30–50%) since affected patients typically have severe underlying medical disease. Bacterial pericarditis is not a primary infection but is almost exclusively a complication from an underlying one.10,11 In one study, 13% of the cases of purulent pericarditis (confirmed by pericardial fluid analysis or at autopsy) were found in patients admitted to the ICU with a diagnosis of sepsis.12 Risk factors include advanced age, diabetes mellitus, untreated infection (pneumonia), extensive burns, an immunosuppressed state, and a preexisting pericardial effusion (renal failure, CHF). The physician must maintain a high index of suspicion in patients with a septic presentation (fever and hypotension) to avoid missing this diagnosis since the only confirmatory test is sampling a known effusion.
The presentation is always acute, with hectic fevers and frank rigors. Tachycardia is invariably present; other findings vary, based on the underlying etiology. An evanescent three-component pericardial rub (early diastole, late diastole, and systole) is found in about one third of cases. Tamponade can develop rapidly, as an effusion of 500 cm3 can accumulate rapidly over several days. It is important to note that after cardiac surgery, the pericardium is not typically closed, so a suppurative infection will not result in tamponade, making the diagnosis even more difficult in these patients.10,11
Previously, the most likely manner a patient developed suppurative pericarditis was through pneumonia with empyema development, so the most common organism was Streptococcus pneumoniae. The accepted etiologies of suppurative pericarditis include seeding from circulating bacteremia, contiguous intrathoracic source (empyema), penetrating trauma, surgical wounds (sternal osteomyelitis), intracardiac source, esophageal rupture with fistula formation, retropharyngeal abscess, and hepatic/subdiaphragmatic abscess. One study by Rubin demonstrated the risk of infectious endocarditis (I.E.) leading to pericardial disease; at autopsy, 13% of patients with I.E. had suppurative pericarditis, and 20% had a myocardial abscess (this figure increased to 36% if the microbe was Staphylococcus aureus).10,13
The current microbiology of pericardial infections has changed with the advent of antibiotics, as well as with the development of thoracic and cardiac surgery. Several recent studies note the trend toward more diverse microbes involved, and an important finding of anaerobes as a common cause. Since anaerobes are the leading flora of the oral cavity, where they outnumber aerobes 100:1, it reasons they would be the infectious agents if the source were esophageal, pharyngeal, GI, or pulmonic (aspiration). One large retrospective study by Brook and Frazier found primary anaerobic infections in 40% of bacterial pericarditis cases and mixed (aerobic/anaerobic) in 13%, but there were no clinical or diagnostic differences found between theses types of infections.13,14
Optimum therapy should include 4 weeks of a bactericidal drug, with the microbe's sensitivity known. Antibiotics penetrate well into the pericardial sac so that intrapericardial instillation is not necessary. Surgical pericardial drainage is also recommended, not only to eradicate gross pus but also to prevent constriction from occurring (a late complication with a variable time course); there has been recent evidence that supports the use of video-assisted thoracoscopic surgery (V.A.T.S.) in place of open thoracotomy.15 If the patient were unable to tolerate these procedures, intrapericardial catheter placement would be advised. This is an old therapy that has had resurgence with multiple recent studies demonstrating its effectiveness and safety. Streptokinase and streptodornase can be instilled and the catheter clamped, and then flushed out and the procedure repeated. These substances aid in the drainage of clotted blood and thickened nucleoproteins (pus) and significantly improve resolution of loculated effusions. This procedure does not affect systemic coagulation studies and has no increased bleeding events associated, but does prevent development of constrictive disease.16,17
Although there are many fungi known to cause purulent pericarditis, Histoplasmosis and Candida are the most common. These organisms usually affect immunosuppressed patients (leukemia, organ transplant, AIDS, long hospital stay on multiple antibiotics), but there are differences between these two organisms.
Histoplasmosis capsulatum spores are found in the soil of the Ohio and Mississippi river valleys, and are inhaled causing a pneumonitis. From there, hematogenous spread occurs to the mediastinal nodes and reticuloendothelial system until cellular immunity develops. In immunocompetent individuals, this process takes about 10–14 days and has a self-limited course. But in an immunosuppressed individual, pericardial disease can occur from the primary infection or at a later time from reactivation; in the latter case, the source is usually adjacent mediastinal nodes, although rarely it is disseminated disease. Ten percent of patients clinically infected will develop pericardial disease.3,4,18
Candida albicans and tropicalis are common host flora that can infect even immunocompetent individuals under certain circumstances. Intravenous drug abuse, indwelling venous catheters (particularly for parenteral nutrition with lipids), thoracic surgery, and prosthetic heart valves are risk factors for pericarditis from these entities. The route is typically hematogenous, intracardiac, or contiguous spread from a surgical site. The presentation for fungal infections is similar to bacterial, but the course is slightly slower in terms of effusion accumulation and pericardial thickening and scarring.
Therapy is similar to that of bacterial pericarditis, with systemic antifungal therapy and open drainage/pericardial resection.3,4,19
Still the leading cause of chronic pericardial disease and constriction worldwide, tuberculosis incidence in the United States fell by 5% per year until 1985 and the increased spread of HIV. TB is now estimated to be the cause of 2–4% of all admitted pericarditis patients and 5–6% of cases with pericardial constriction. The reported incidence of pericardial involvement among patients with pulmonary tuberculosis ranges from 1% to 8%; evidence of active pulmonary disease at the time is rare, however, with only 11–50% of patients with pericarditis having positive sputum cultures.13,20 Pericardial involvement can occur with a primary infection or reactivation of latent infection. The most common pathway is retrograde extension via lymphatics from peribronchial and mediastinal nodes; other recognized pathways include hematogenous spread from distant foci (genitourinary or skeletal) and direct extension from a contiguous source (lymph nodes, lung, pleura, spine).
Four pathologic stages have been identified: (1) fibrinous—fibrin deposition with many PMNs, abundant organisms, and loose granuloma formation; (2) effusive—serosanguineous effusion accumulation with lymphocytes and monocytes predominating; (3) absorptive—effusion diminishes, mycobacterium cells are now scarce, and dense caseating granulomas thicken the pericardium; (4) constrictive—granulomas replaced by fibrous tissue that begins to contract. Calcification may occur at any pathologic stage.3,20,21
Unlike bacterial pericarditis, these patients have a subacute/chronic course. The onset is insidious, with nonspecific features only, until late in the course. Diagnosis can be made by stain or culture of pericardial fluid, although this is only positive in 15% of patients clinically diagnosed with tubercular disease. These figures can be improved by doing ELISA and PCR assays on the fluid. Pericardial biopsy is thought to have the highest diagnostic yield, although still not 100%, and is dependent on the stage of disease and amount of tissue obtained. PPD testing is not helpful since patients may be anergic (low sensitivity), or may be reactive but have no pericardial involvement (low specificity). Treatment consists of four-drug therapy for at least 1 month, followed by two-drug therapy for 1–2 years. Careful follow-up is needed to evaluate for signs of constriction, and some recommend pericardiectomy as initial therapy due to the high percentage (30–50%) of appropriately treated patients that still develop constriction by 4 months. Steroids should also be given in the first month; they have been shown to significantly decrease mortality and improve patient symptoms, although they have little effect on pericardial constriction.2,20,21
Significant cardiac morbidity due to HIV disease is estimated at 6–7%, with pericardial effusion and myocarditis the most common abnormalities. At autopsy, 40% of patients have large effusions, and several studies have found that an effusion is an independent risk factor (separate from CD4 count) for decreased survival. In a study of HIV patients, 25% had an effusion by echocardiography, of which 20% were large. The majority were asymptomatic, and at follow-up 42% of the effusions had spontaneously resolved. Still, in a series of patients requiring intervention for tamponade, the most common underlying disorders were malignancy and HIV.22
Pericardial disease can result from opportunistic infections, medical treatment of HIV, and the HIV itself. In these immunocompromised patients, one must consider not only viral and bacterial pathogens but also fungal, mycobacterial, and parasitic infections,23,24 as well as noninfectious causes such as lymphoma and Kaposi's sarcoma. The risk factors for death associated with moderate–severe pericardial effusion are tuberculosis (OR 47.2), heart failure (OR 30.3), other pulmonary infection (OR 15.0), and Kaposi's sarcoma (OR 8.6). Based on this information, it would be prudent for an HIV patient symptomatic with a persistent pericardial effusion to be empirically treated for tuberculosis until that diagnosis can be excluded.23
Uremic pericarditis occurs in 6–10% of patients with advanced renal disease before or shortly after starting dialysis and correlates with the degree of azotemia; it is unusual to occur with a BUN <60 mg/dL. Treatment is initiation or intensification of dialysis with avoidance of heparin because of concern for a hemorrhagic effusion. Dialysis-associated pericarditis occurs in 13% of patients receiving hemodialysis and, occasionally, peritoneal dialysis; the etiology and treatment are unclear.3,6
Pericarditis can occur early in the first few days post-MI due to transmural infarction that causes inflammation of the local pericardium. It is a marker of larger infarct size, but it is not associated with increased morbidity or mortality. The incidence has decreased significantly since reperfusion therapies have become the standard of care for MI.25 Treatment is full-dose aspirin while avoiding other NSAIDs or steroids that prevent scar formation and may increase the incidence of myocardial rupture. Delayed pericarditis, also known as Dressler's syndrome, is due to a diffuse immunopathologic process involving the entire pericardium and is the same etiology of postpericardiotomy syndrome. It is best treated with ibuprofen or colchicine.5,25,26
Pericarditis is associated with numerous autoimmune and collagen-vascular diseases. It is necessary to first evaluate for uremic, infectious, or neoplastic causes. But once these are ruled out, intensifying treatment of the underlying conditions and symptomatic analgesics are helpful. Intrapericardial steroids offer extended effectiveness without the systemic adverse effects.27,28
Mesothelioma is the most common primary pericardial malignancy, but metastatic cancers (lung, breast, lymphoma, melanoma) are 40 times more likely to cause pericardial disease. Twenty percent of large effusions without an obvious cause have been found to be due to an undiagnosed malignancy. Neoplastic effusions are typically exudative, fibrinous, and hemorrhagic, and often require open surgical drainage. Intrapericardial chemotherapy and sclerosing agents are an option if tamponade does not exist.3,29
Hemopericardium may occur secondary to penetrating or blunt chest trauma; pericardial rupture may occur following blunt injuries causing cardiac herniation that presents as tamponade. Seventeen to 45% of type A aortic dissections are complicated by hemopericardium. In these cases, unless the patient is in extremis due to tamponade, pericardiocentesis is contraindicated due to potentially extending the dissection.30 Invasive procedures, such as endomyocardial biopsy, electrophysiology (EP) studies, permanent pacemaker insertion, and coronary angiography, can cause unintended cardiac or vascular perforation producing tamponade. EP procedures have a 1–6% risk of cardiac perforation with the risk increased by higher energy use and ablations for atrial fibrillation. Coronary perforation occurs in 0.1–0.6% of all PCI resulting in 42% mortality; its risk is increased by atheroablative procedures. The immediate treatment is to seal the coronary injury and reverse all anticoagulation while monitoring closely for tamponade.4,30
Pericardial tamponade is due to pericardial pressure exceeding cardiac chamber diastolic pressure, therefore not allowing filling to occur. While there are several risk factors for developing pericardial tamponade (Table 18-3), only three factors determine the clinical presentation: (1) volume of fluid; (2) rate at which fluid accumulates; (3) pericardial compliance. The pressure–volume curve is nonlinear, with the initial flat section due to the pericardial reserve volume. This volume is made up of the recesses and sinuses of the pericardial sac (Figure 18-2). The gradual upslope of the curve is due to the elastic fibers stretching and the wavy collagen fibers straightening. The steep slope is due to the exhaustion of these mechanisms, and any increase in volume above that critical point causes severe increases in pressure that are transduced as compressive forces on the heart. If the fluid accumulates rapidly or if the pericardium is pathologically stiff, then relatively small amounts of fluid can result in marked elevations in pressure. In contrast, if the effusion grows slowly, the pericardium can gradually stretch to accommodate the volume, stretching the pressure–volume curve to the right.2,4,31
Cardiac tamponade. Pericardial pressure–volume (or strain–stress) curves are shown in which the volume increases slowly or rapidly over time. In the left-hand panel, rapidly increasing pericardial fluid first reaches the limit of the pericardial reserve volume (the initial flat segment) and then quickly exceeds the limit of parietal pericardial stretch, causing a steep rise in pressure, which becomes even steeper as smaller increments in fluid cause a disproportionate increase in the pericardial pressure. In the right-hand panel, a slower rate of pericardial filling takes longer to exceed the limit of pericardial stretch, because there is more time for the pericardium to stretch and for compensatory mechanisms to become activated. (Reproduced with permission from DH Spodick. N Engl J Med. 2003;349(7):684–690.)
Table 18-3. Common Risk Factors for Pericardial Tamponade |Favorite Table|Download (.pdf)
Table 18-3. Common Risk Factors for Pericardial Tamponade
- History of pericarditis
- Blunt or penetrating chest trauma
- Cardiac surgery
- Cardiac catheterization (PCI or EP study)
- Known or suspected intrathoracic neoplasm
- Known or suspected aortic dissection
- Renal failure or hemodialysis
Symptoms of tamponade include dyspnea, tachypnea, and fatigue, while signs include tachycardia, elevated jugular venous distension, a quiet precordium, hypotension, and pulsus paradoxus. Another notable finding is dullness to percussion at the left scapular angle with bronchial breath sounds due to compressive atelectasis from the effusion. It is often commented that a pericardial rub disappears when an effusion develops, but a rub may still be present (typically on inspiration) caused by pericardial–pleural friction. The elevated pericardial pressure results in elevated right atrial and venous pressure giving a characteristic jugular venous waveform lacking the Y descent. These changes result from decreased right atrial emptying due to impaired ventricular expansion and filling.4,31,32
The description of pulsus paradoxus by Kussmaul in 1873 was of the “paradox” of not palpating a pulse despite detecting a heartbeat during inspiration. It has since been described in patients with normal physiology that during inspiration there is a consistent decrease in left ventricular stroke volume (7%) and arterial pressure (3%). These effects are due to ventricular interdependence and can be accentuated in pericardial disease, leading to the suggested renaming of the finding as pulsus exageratus (Figure 18-3). It is thought to be pathognomonic of tamponade when positive (inspiratory drop in SBP of 10% or 10 mm Hg), but there can be false positives as well as false negatives. A pulsus exageratus may be present without tamponade in severe COPD/asthma or with a large pulmonary embolism; exaggeration of intrathoracic pressures is believed to be responsible. Tamponade may be present without a pulsus in hypovolemia, called low-pressure tamponade; if blood volume/preload is already diminished, minimal increases in pericardial pressure limit right-sided filling without causing an effect on left-sided function. Alternatively, an atrial septal defect will shunt blood from left to right, nullifying ventricular interdependence. Finally, right ventricular hypertrophy causing a thick, noncompliant septum, aortic regurgitation, congestive heart failure, and severe left ventricular hypertrophy all increase LVEDP; these conditions also limit ventricular interdependence and therefore limit the formation of a pulsus.4,31,32
Schematic representation of the competitive ventricular filling that occurs during respiration with pericardial tamponade. (Reproduced with permission from Cosio FG, et al. Abnormal septal motion in cardiac tamponade with pulsus paradoxus. Chest. 1977;71:787.)
There are several diagnostic tests that can assist in the diagnosis of tamponade; a chest radiograph is not one of them since it gives only static anatomic data, not dynamic functional data. Acutely the pericardial silhouette will be normal, requiring approximately 250 cm3 of fluid to gather before it assumes a globular shape (Figure 18-4). But even if this finding is present, it still does not prove the effusion is causing any pathologic effects. Likewise, there are EKG findings suggestive of pericarditis (diffuse ST abnormalities; Figure 18-5) or an effusion (low voltages due to insulating effects, and electrical alternans; Figure 18-6), but these also are not helpful in diagnosing tamponade.5,30
Chest radiograph of an asymptomatic patient with a large effusion due to severe CHF.
An EKG of an adolescent with fever and chest pain during an episode of diabetic ketoacidosis. Note ST-segment elevations in all leads except aVL (an isoelectric lead here so the ST segment is compressed) and aVR and V1, which have expected ST-segment depressions. PR-segment depression is best seen in lead II.
EKG of a patient with ESRD on chronic hemodialysis with a large, symptomatic effusion. Electrical alternans is present with the voltages varying over a three-beat cycle. Mild tachycardia (rate 102) and low voltages in the limb leads are also present. A pericardial window was performed.
Echocardiography is a valuable noninvasive means to evaluate a patient for tamponade, but it should be remembered that no single finding has 100% sensitivity or specificity. The presence of an effusion, graded as small (posterior only), moderate (anterior also but <1 cm), or large (>1 cm), is required, but alone does not confirm tamponade (Figure 18-7). Right atrial collapse is more sensitive but less specific for tamponade than ventricular diastolic collapse (collapse occurs when chamber pressures are lowest) (Figure 18-8). The absence of IVC plethora (suggesting normal right atrial pressure) makes the diagnosis of tamponade unlikely. Flow velocity paradoxus, the immediate marked decrease in transmitral (and increase in transtricuspid) Doppler flow with inspiration, like the pulsus, is an accentuation of normal physiology.33,34
Subxiphoid pericardial ultrasound reveals a large pericardial fluid collection. (Reproduced with permission from Brunicardi FC, Andersen DK, Billiar TR, et al. Schwartz's Principles of Surgery. 9th ed. New York, NY: McGraw-Hill Inc; 2010. Figure 7-9.)
RV compression (arrow) in cardiac tamponade (apical four-chamber plane). RA, right atrium; RV, right ventricle; LV, left ventricle; E, effusion. (Reproduced with permission from Fuster V, O'Rourke RA, Walsh RA, Poole-Wilson P. Hurst's the Heart. 12th ed. New York, NY: McGraw-Hill Inc; 2008. Figure 16-135B.)
On right heart catheterization, pulmonary artery wedge pressure and atrial and ventricular end-diastolic pressures are elevated and equalized (within 5 mm Hg) in tamponade. These values reflect the elevated intrapericardial pressure, but again there are other pathologic conditions that can cause diastolic equalization of pressure.
For hemodynamically stable patients (including those patients stabilized with the use of fluids and vasopressors), a controlled drainage of the effusion under guided imaging is preferable. This procedure can be done bedside with echocardiography, or in the cardiac catheterization lab under fluoroscopy while monitoring right and left heart pressures. A catheter is usually left in the pericardium for at least 72 hours to continue draining any recurrent effusion. Surgical drainage employing either a subxyphoid pericardial window or an open thoracotomy is also an option.
For hemodynamically unstable patients, immediate relief of the tamponade by percutaneous subxyphoid needle aspiration is required (Figure 18-9). The patient should be positioned upright at 45° in order to have gravity assist the fluid into a dependent position anteriorly. If ultrasonography is not available, a precordial lead can be clipped to the metal hub of the needle, and a continuous EKG strip is run while aspirating; epicardial contact is indicated by ST-segment elevation or PVCs indicating the needle should be withdrawn slightly. Potential serious complications include ventricular puncture, coronary artery laceration, and pneumothorax.30,35
The paraxiphoid technique for pericardiocentesis is usually performed with the needle directed toward the left shoulder or left scapula tip. However, if one aims toward the tip of the right scapula, the needle tends to go parallel to the lateral border of the right heart and is less apt to penetrate the coronary artery or myocardium. (Reproduced with permission from Wilson RF. Injury to the heart and great vessels. In: Henning RS, ed. Critical Care Cardiology. New York, NY: Churchill Livingstone; 1989.)
Constriction has been referred to as pseudocirrhosis because of its ability to mimic chronic liver disease. The most common etiologies include postradiation, lung and breast cancer, TB, and renal failure. The final common pathway is thickening and scarring of the pericardial layers, which, in turn, become adherent, obliterating the pericardial space. There can be focal disease, usually involving the apex and the right atrium (particularly the atrial–ventricular groove), due to increased local friction, and a minority of cases can have constriction resulting from the visceral pericardium alone.1,3 Whatever the cause or location, the fibrotic encasement causes a fixed diastolic chamber volume with impaired expansion and an isolation of the cardiac chambers from changes in intrathoracic pressure.
Normally, the majority of ventricular filling occurs in phase 2 (rapid filling) of diastole, with up to 20% during phase 4 (atrial contraction), and increasing heart rate shortens diastole, thereby decreasing filling. With constriction, elevated atrial pressures cause increased ventricular filling (75%) in the first phase of diastole, which is then halted abruptly by mid-diastole. In this case, increasing heart rate actually improves cardiac output since very little filling occurs in the shortened late diastole.
With the abrupt cessation of filling, a “knock” is produced in 30–70% of patients; it is a loud diastolic sound 0.6–0.12 seconds after S2, but of higher frequency than an S3. Respiratory pressure variations are still transmitted to other intrathoracic structures (vena cava, pulmonary vasculature) but not to the heart. Inspiration reduces the pressure gradient between the pulmonary veins and the left heart, resulting in decreased diastolic flow and ventricular filling; based on accentuated ventricular interdependence, the septum shifts leftward allowing a simultaneous increase in right ventricular filling. The opposite effects are seen with expiration. In pure constrictive pericarditis (CP), the pulsus is usually less than 10 mm Hg and, if greater, it suggests concomitant tamponade (effusive–constrictive pericarditis).1,3,36
The onset of constrictive disease is typically insidious, with symptoms developing from weeks to decades after the inciting event. In one study by Ling, the average duration of symptoms prior to a diagnosis was 23.4 months. Peripheral edema, abdominal swelling (from hepatomegaly or ascites), dyspnea, and orthopnea are common initial complaints, illustrating the potential confusion with intrinsic liver disease. Physical exam will reveal elevated JVP in 96% of patients, and Kussmaul's sign (paradoxical increase in JVP with inspiration, since the right atrium cannot accommodate the increased venous return) may be present. It is not specific for constriction, however, and may be seen in any condition with elevated right heart pressures including right ventricular infarct, pulmonary hypertension, tricuspid stenosis, and restrictive cardiomyopathy (RCM). Early cessation of diastolic filling produces Fridreich's sign, a rapid Y descent of the JVP, seen in 94% of cases in one series. A dampened apical impulse and a pericardial knock, more prominent with squatting but attenuated by nitroglycerin, are also common findings. Pulsatile hepatomegaly with ascites was found in 70% of patients in one study, but there are differences in the liver function tests and ascitic fluid analysis of these patients with passive congestion compared with those of cirrhotic patients as seen in a study by Runyon.36,37
EKG findings include low voltages (60%) and atrial fibrillation in the late stages (25%), although these are insensitive and nonspecific. Diagnosis can be made by CT or MRI, demonstrating a pericardial thickness of greater than 4 mm, sometimes with calcifications, but since there may be focal disease only, relying on these modalities will miss a certain percentage of cases. Echocardiography can be useful in evaluating for constriction, with transesophageal being superior to transthoracic echo in detecting pericardial thickening. Other echo findings include preserved systolic function with rapid diastolic filling causing exaggerated posterior wall and septal motion (septal bounce), early closure of the mitral valve, and premature opening of the tricuspid valve.
RCM, such as caused by amyloidosis, sarcoidosis, hemochromatosis, glycogen storage diseases, or endomyocardial elastosis, may have a similar clinical presentation and echo abnormalities to constrictive pericarditis, and it is still a challenge for cardiologists to differentiate the entities (short of sending a patient for a thoracotomy). There have been studies that have found a faster filling rate with a shorter interval to peak filling in constriction, and Garcia et al. used Doppler tissue imaging to show that left ventricular expansion peak velocity is markedly reduced in restrictive disease, but is preserved in constriction.38
Cardiac catheterization can also be used to help make the diagnosis, but again there is overlap of many of the findings with RCM. Right atrial pressure tracings show the typical M or W pattern formed by the prominent Y descent. Diastolic pressures are elevated and approximately equal in all four chambers, with simultaneous ventricular tracings giving a characteristic dip and plateau pattern (square root sign); RVEDP has been found to be at least one third of RVSP in 95% of constriction. If all chamber diastolic pressures are low, and there is clinical suspicion of CP, a rapid infusion of 1 L of saline may be given to identify occult disease; in a normal patient, the pressures should rise and separate, but with CP they rise and remain equally related.4,39
Medical therapy using diuretics may be initially attempted, but the overwhelming majority of patients will require pericardiectomy as definitive therapy. In a large series from the Mayo Clinic, preoperative risk factors were identified as severity of RVEDP elevation, renal insufficiency, and previous mediastinal radiation; intraoperative risk factors that worsen prognosis were unresectable calcifications and incomplete decortication (usually due to involvement of the epicardium). Poor postoperative response is found when the fibrosis and calcification had progressed to involve the myocardium also. Operative mortality is based on NYHA functional class status, with 1% for class I or II, 10% for class III, and 46% for class IV; these data illustrate the importance of making the diagnosis sooner rather than later.36,37