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Pericarditis
is inflammation of the pericardium, often with fluid accumulation.
Pericarditis may be caused by many disorders (eg, infection, MI, trauma,
tumors, metabolic disorders) but is often idiopathic. Symptoms include
chest pain or tightness, often worsened by deep breathing. Cardiac output
may be greatly reduced. Diagnosis is based on symptoms, a friction
rub, ECG changes, and evidence of pericardial fluid accumulation
on x-ray or echocardiogram. Finding the cause requires further evaluation.
Treatment depends on the cause, but general measures include analgesics,
anti-inflammatory drugs, and sometimes surgery.
Pericarditis is the most common pericardial disorder. Congenital pericardial disorders are rare.
Anatomy
and Pathophysiology
The pericardium has 2 layers. The visceral pericardium is a single layer of mesothelial cells that is attached to the myocardium, folds back (reflects) on itself over the origin of the great vessels, and joins with a tough, fibrous layer to envelop the heart as the parietal pericardium. The sac created by these layers contains a small amount of fluid (< 25 to 50 mL), composed mostly of an ultrafiltrate of plasma. The pericardium limits distention of the cardiac chambers and increases the heart's efficiency.
The pericardium is richly innervated with sympathetic and somatic afferents. Stretch-sensitive mechanoreceptors sense changes in cardiac volume and tension and may be responsible for transmitting pericardial pain. The phrenic nerves are embedded in the parietal pericardium and are vulnerable to injury during surgery on the pericardium.
Pericarditis may be acute or chronic. Acute pericarditis develops quickly, producing an inflammatory reaction. Chronic pericarditis (defined as persisting > 6 mo) develops more slowly; its prominent feature is effusion. Acute disease may become chronic. Adverse hemodynamic effects and rhythm disturbance are rare, although cardiac tamponade is possible. Occasionally, pericarditis produces a marked thickening and stiffening of the pericardium (constrictive pericarditis). Pericarditis can lead to inflammation of the epicardial myocardium.
Pericardial
effusion is accumulation of fluid in the pericardium. The fluid may be serous fluid (sometimes with fibrin strands), serosanguineous fluid, blood, pus, or chyle.
Cardiac
tamponade occurs when a large pericardial effusion impairs cardiac filling, leading to low cardiac output and sometimes shock and death. If fluid (usually blood) accumulates rapidly, even small amounts (eg, 150 mL) may produce tamponade because the pericardium cannot stretch quickly enough to accommodate it. Slow accumulation of up to 1500 mL may not produce tamponade. Loculated effusion may produce localized tamponade on the right or left side of the heart.
Constrictive
pericarditis, which is uncommon, results from marked inflammatory, fibrotic thickening of the pericardium. Sometimes the visceral and parietal layers adhere to each other or to the myocardium. The fibrotic tissue often contains Ca deposits. The stiff, thickened pericardium markedly impairs ventricular filling, decreasing stroke volume and cardiac output. Significant pericardial fluid accumulation is rare. Rhythm disturbance is common. The diastolic pressures in the ventricles, atria, and venous beds become virtually the same. Systemic venous congestion occurs, causing considerable transudation of fluid from systemic capillaries, with dependent edema and, later, ascites. Chronic elevation of systemic venous and hepatic venous pressure may lead to cardiac cirrhosis. Constriction of the left atrium, the left ventricle, or both may elevate pulmonary venous pressure.
Etiology
Acute pericarditis may result from infection, autoimmune and inflammatory disorders, uremia, trauma, MI, or certain drugs (see Table 1: Pericarditis: Causes of Acute Pericarditis ). Infectious pericarditis is most often viral. Purulent bacterial pericarditis is uncommon but may follow infective endocarditis, pneumonia, septicemia, penetrating trauma, or cardiac surgery. Often, the cause cannot be identified (called nonspecific or idiopathic pericarditis), but many of these cases are probably viral. Overall, the most common causes are viral and idiopathic. Acute MI causes 10 to 15% of cases of acute pericarditis. Post-MI syndrome (Dressler's syndrome) is a less common cause now, occurring mainly when reperfusion with percutaneous transluminal coronary angioplasty (PTCA) or thrombolytic drugs is ineffective in patients with transmural infarction. Pericarditis occurs after pericardiotomy (called postpericardiotomy syndrome) in 5 to 30% of cardiac operations.
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Table 1
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Causes of Acute Pericarditis
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Idiopathic
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Viral infections (echovirus, influenza virus, coxsackie B virus, HIV*)
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Bacterial infections† (streptococci; staphylococci; gram-negative bacilli; in children, Haemophilus influenzae)
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Fungal infections (histoplasmosis, coccidioidomycosis, candidiasis, blastomycosis)
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Parasitic infections (toxoplasmosis, amebiasis, echinococcosis)
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Autoimmune disorders (RA, SLE, scleroderma)
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Inflammatory disorders (amyloidosis, inflammatory bowel disease, sarcoidosis)
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Uremia
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Trauma
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MI
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Post-MI (Dressler's) syndrome
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Post pericardiotomy
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Drugs (eg, hydralazine, isoniazid, methysergide, phenytoin, procainamide)
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*If patients with AIDS develop lymphoma, Kaposi's sarcoma, or certain infections (ie, Mycobacterium avium, M. tuberculosis, Nocardia, other fungal or viral infections), pericarditis may follow.
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†Tuberculous pericarditis accounts for < 5% of cases of acute or subacute pericarditis in the US but the majority of cases in some areas of India and Africa.
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Chronic pericardial effusion or constrictive pericarditis may follow almost any disorder that causes acute pericarditis, as well as TB, tumor, irradiation, rheumatoid disease, and cardiac surgery. Sometimes no cause of chronic pericarditis is identified. Pericarditis with large effusion (serous, serosanguineous, or bloody) is most commonly caused by metastatic tumors, most often by lung or breast carcinoma, sarcoma (especially melanoma), leukemia, or lymphoma.
Fibrosis of the pericardium may follow purulent pericarditis or myocardial infection (myocarditis—a common cause in young people) or accompany a connective tissue disorder. In elderly patients, common causes are malignant tumors, MI, and TB. Hemopericardium (accumulation of blood within the pericardium) may lead to pericarditis or pericardial fibrosis; common causes include chest trauma, iatrogenic injury (eg, from cardiac catheterization, pacemaker insertion, or central venous line placement), and rupture of a thoracic aortic aneurysm.
Symptoms,
Signs, and Diagnosis
Some patients present with symptoms and signs of inflammation (acute pericarditis); others present with those of fluid accumulation (pericardial effusion). Symptoms and signs vary depending on the severity of inflammation and the amount and rate of fluid accumulation. Even a large amount of pericardial fluid may be asymptomatic if it develops slowly (eg, over months).
Acute pericarditis:
Acute pericarditis tends to cause chest pain and a pericardial rub, sometimes with dyspnea. The first evidence can be tamponade, with hypotension, shock, or pulmonary edema.
Because the innervation of the pericardium and myocardium is the same, the chest pain of pericarditis is sometimes similar to that of myocardial inflammation or ischemia: Dull or sharp precordial or substernal pain may radiate to the neck, trapezius ridge (especially the left), or shoulders. Pain ranges from mild to severe. Unlike ischemic chest pain, pain due to pericarditis is usually aggravated by thoracic motion, cough, breathing, or swallowing food; it may be relieved by sitting up and leaning forward. Tachypnea and nonproductive cough may be present; fever, chills, and weakness are common. In 15 to 25% of patients with idiopathic pericarditis, symptoms recur intermittently for months or years.
The most important physical finding is a triphasic or a systolic and diastolic precordial friction rub. However, the rub is often intermittent and evanescent; it may be present only during systole or, less frequently, only during diastole. If no rub is heard with the patient seated and leaning forward, auscultation may be attempted with the patient on all fours and listening with the diaphragm of the stethoscope. Sometimes, a pleural component to the rub is noted during breathing, which is due to inflammation of the pleura adjacent to the pericardium. Considerable amounts of pericardial fluid may muffle heart sounds, increase the area of cardiac dullness, and change the size and shape of the cardiac silhouette.
If acute pericarditis is suspected, hospitalization is sometimes required for initial evaluation. ECG and chest x-ray are done. If symptoms or signs of elevated right-sided pressure, tamponade, or an enlarged cardiac silhouette are present, echocardiography to check for effusion and cardiac filling abnormalities is also done. Blood tests may detect leukocytosis and an elevated ESR, but these findings are nonspecific.
The diagnosis is based on the presence of typical clinical findings and ECG abnormalities. Serial ECGs may be needed to show abnormalities.
The ECG in acute pericarditis may show abnormalities confined to ST segments and T waves, usually in most leads (see Fig. 1: Pericarditis: Acute pericarditis: Stage 1 ECG. ). The ST segments in 2 or 3 of the standard leads become elevated but subsequently return to baseline. Unlike MI, acute pericarditis does not cause reciprocal depression in ST segments (except in leads aVR and V1), and there are no pathologic Q waves. The PR segment may be depressed. After several days or longer, T waves may become flattened and then inverted throughout the ECG, except in lead aVR; T-wave inversion occurs after the ST segment has returned to baseline and thus differs from the pattern of acute ischemia or MI.
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Fig. 1
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Acute pericarditis: Stage 1 ECG.
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J points, except aVR and V1, are elevated. T waves are essentially normal. PR segments, except aVR and V1, are depressed. PR deviations are commonly absent in one limb lead (here, aVL).
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Because the pain of pericarditis may resemble that of acute MI or pulmonary infarction, additional tests (eg, serum cardiac marker measurement, lung scan) may be required if the history and ECG findings are atypical for pericarditis. Troponin is almost always elevated in acute pericarditis due to epicardial inflammation so it cannot discriminate between acute infarction and pulmonary embolism. The CPK level is usually normal in acute pericarditis unless myocarditis is also present.
Postpericardiotomy and post-MI syndromes may be difficult to identify and must be distinguished from recent MI, pulmonary embolism, and pericardial infection after surgery. Pain, friction rub, and fever appearing 2 wk to several months after surgery and a rapid response to aspirin , NSAIDs, or corticosteroids aid diagnosis.
Pericardial
effusion:
Pericardial effusion is often painless, but when it occurs with acute pericarditis, pain may be present. Typically, heart sounds are muffled. A pericardial rub may be heard. With large effusions, compression of the base of the left lung can decrease breath sounds (heard near the left scapula) and produce crackles (rales). Arterial pulse, jugular venous pulse, and BP are normal unless intrapericardial pressure increases substantially, causing tamponade.
In the post-MI syndrome, pericardial effusion can occur with fever, friction rub, pleurisy, pleural effusions, and joint pain. This syndrome usually occurs within 10 days to 2 mo after MI. It is usually mild but may be severe. Occasionally, the heart ruptures post-MI, causing hemopericardium and tamponade, usually 1 to 10 days post-MI and more commonly in women.
Diagnosis is suggested by clinical findings but often is suspected only after finding an enlarged cardiac silhouette on chest x-ray. On ECG, QRS voltage is often decreased, and sinus rhythm remains in about 90% of patients. With large, chronic effusions, the ECG may show electrical alternans (ie, P, QRS, or T wave amplitude increases and decreases on alternate beats). Electrical alternans is associated with variation in cardiac position (swinging heart). Echocardiography has a high degree of sensitivity and specificity for detecting pericardial fluid.
Patients with a normal ECG, small (< 0.5 L) effusion, and no suspicious findings from the history and examination may be observed with serial examination and echocardiography. Other patients must be evaluated further to determine etiology.
Cardiac
tamponade:
The clinical findings are similar to those of cardiogenic shock: decreased cardiac output, low systemic arterial pressure, tachycardia, and dyspnea. Neck veins are markedly dilated. Severe cardiac tamponade is nearly always accompanied by a fall of > 10 mm Hg in systolic BP during inspiration (pulsus paradoxus—see Approach to the Cardiac Patient: Pulsus paradoxus). In advanced cases, pulse may disappear during inspiration. (However, pulsus paradoxus can also occur in COPD, bronchial asthma, pulmonary embolism, right ventricular infarction, and noncardiogenic shock.) Heart sounds are muffled unless the effusion is small.
Low voltage and electrical alternans on the ECG suggest cardiac tamponade, but these findings lack sensitivity and specificity. When tamponade is suspected, echocardiography is done unless even a brief delay might be life threatening. Then pericardiocentesis is done immediately for diagnosis and treatment. On an echocardiogram, respiratory variation of transvalvular and venous flows and compression or collapse of right cardiac chambers in the presence of a pericardial effusion support the diagnosis.
If tamponade is suspected, right heart (Swan-Ganz) catheterization may be done. In cardiac tamponade, there is no early diastolic dip in the ventricular pressure record. In the atrial pressure curve, x descent is preserved and y descent is lost. In contrast, in severe congestive states due to dilated cardiomyopathy, pulmonary artery occlusion or left ventricular diastolic pressure usually exceeds right atrial mean pressure and right ventricular diastolic pressure by ≥ 4 mm Hg.
Constrictive
pericarditis:
Fibrosis or calcification rarely produces symptoms unless constrictive pericarditis develops. The only early abnormalities may be elevated ventricular diastolic, atrial, pulmonary, and systemic venous pressures. Symptoms and signs of peripheral venous congestion (eg, peripheral edema, neck vein distention, hepatomegaly) may appear with an early diastolic sound (pericardial knock), often best heard during inspiration. This sound is due to abrupt slowing of diastolic ventricular filling by the rigid pericardium. Ventricular systolic function (based on ejection fraction) is usually preserved. Prolonged elevation of pulmonary venous pressure results in dyspnea (particularly during exertion) and orthopnea. Fatigue may be severe. Distention of neck veins with a rise in venous pressure during inspiration (Kussmaul's sign) is present; it is absent in tamponade. Pulsus paradoxus is rare and is usually less severe than in tamponade. Lungs are not congested unless severe left ventricular constriction develops.
Diagnosis may be suspected based on ECG, chest x-ray, and Doppler echocardiography findings, but cardiac catheterization and CT (or MRI) are usually required. Because ventricular filling is restricted, ventricular pressure tracings show a sudden dip followed by a plateau (resembling a square root sign) in early diastole. Rarely, right heart biopsy is needed to exclude restrictive cardiomyopathy.
ECG changes are nonspecific. QRS voltage is usually low. T waves are usually nonspecifically abnormal. Atrial fibrillation occurs in about 1⁄3 of patients; atrial flutter is less common.
Lateral chest x-rays often show pericardial calcification best, but the finding is nonspecific.
The changes on echocardiogram are also nonspecific. When the right and left ventricular filling pressures are equally elevated, Doppler echocardiography helps distinguish constrictive pericarditis from restrictive cardiomyopathy. During inspiration, mitral diastolic flow velocity usually falls > 25% in constrictive pericarditis but < 15% in restrictive cardiomyopathy. In constrictive pericarditis, inspiratory tricuspid flow velocity increases more than it normally does, but it does not do so in restrictive cardiomyopathy. Determining tissue velocities at the mitral annulus may be helpful when excessively high left atrial pressure blunts respiratory variation in transvalvular velocities.
If clinical and echocardiographic findings suggest constrictive pericarditis, right heart cardiac catheterization is done. It helps confirm and quantify the abnormal hemodynamics that define constrictive pericarditis: Mean pulmonary artery occlusion pressure (pulmonary capillary wedge pressure), pulmonary artery diastolic pressure, right ventricular end-diastolic pressure, and mean right atrial pressure are all at about 10 to 30 mm Hg. The pulmonary artery and right ventricular systolic pressures are normal or modestly elevated, so that pulse pressures are small. In the atrial pressure curve, x and y descents are typically accentuated; in the ventricular pressure curve, a diastolic dip occurs at the time of rapid ventricular filling. These changes almost always occur with significant constrictive pericarditis.
Right ventricular systolic pressure of > 50 mm Hg often occurs in restrictive cardiomyopathy but less often in constrictive pericarditis. When the pulmonary artery occlusion pressure equals the right atrial mean pressure and an early diastolic dip in the ventricular pressure curve occurs with large x and y waves in the right atrial curve, either disorder may be present.
CT or MRI can identify pericardial thickening > 5 mm. Such thickening with typical hemodynamic changes can confirm a diagnosis of constrictive pericarditis. When no pericardial thickening or fluid is seen, the diagnosis of restrictive cardiomyopathy is favored but not proved; a normal pericardial thickness does not exclude the diagnosis of constrictive pericarditis.
Diagnosis of
cause:
After pericarditis is diagnosed, tests to determine etiology and the effect on cardiac function are done. In a young, previously healthy adult who presents with a viral infection and pericarditis, an extensive evaluation is usually unnecessary. Differentiating viral from idiopathic pericarditis is difficult, expensive, and generally of little practical importance.
A biopsy of pericardial tissue or aspiration of pericardial fluid may be needed to establish a diagnosis. Acid-fast stains and cultures of pericardial fluid help identify infectious causes. Samples are examined for malignant cells. However, complete drainage of a newly identified pericardial effusion is usually unnecessary for diagnosis. Persistent (usually > 3 mo) or progressive effusion, particularly when the etiology is uncertain, also warrants pericardiocentesis.
The choice between needle pericardiocentesis and surgical drainage depends on institutional resources and physician experience, the etiology of the effusion, the need for diagnostic tissue samples, and the prognosis of the patient. Needle pericardiocentesis is often best when the etiology is known or the presence of tamponade is in question. Surgical drainage is best when the presence of tamponade is certain but the etiology is unclear.
Laboratory tests of pericardial fluid other than culture and cytology are usually nonspecific. But specific diagnoses are sometimes possible using newer visual, cytologic, and immunologic analysis of fluid obtained via pericardioscopic-guided biopsy.
Cardiac catheterization is useful for evaluating pericarditis and identifying the cause of reduced cardiac function.
CT or MRI can help identify metastases, although echocardiography is usually sufficient.
Other tests include CBC, acute-phase reactants, routine chemistries, cultures, autoimmune tests, and, when appropriate, tests for HIV, histoplasmosis complement fixation (in endemic areas), streptozyme, and neutralizing antibodies for coxsackievirus, influenza virus, and echovirus. Anti-DNA and anti-RNA antibody tests may be useful. A PPD skin test is done.
Treatment
Hospitalization to watch for complications is usually advisable. Possible causative drugs (eg, anticoagulants, procainamide , phenytoin ) are stopped. For cardiac tamponade, immediate pericardiocentesis (see Fig. 2: Pericarditis: Pericardiocentesis.) is done; removal of even a small volume of fluid may be lifesaving.
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Fig. 2
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Pericardiocentesis.
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Except in emergencies (eg, cardiac tamponade), pericardiocentesis, a potentially lethal procedure, should be done using echocardiographic guidance in a cardiac catheterization laboratory and should be supervised by a cardiologist or thoracic surgeon if possible. Resuscitation equipment must be at hand. IV sedation (eg, morphine 0.1 mg/kg or meperidine 1 mg/kg plus midazolam 3 to 5 mg) is desirable. The patient should be recumbent, with the head elevated 30° from the horizontal. Under aseptic conditions, the skin and subcutaneous tissues are infiltrated with lidocaine . A 75-mm short-beveled, 16-gauge needle is attached via a 3-way stopcock to a 30- or 50-mL syringe. The pericardium may be entered via the right or left xiphocostal angle or from the tip of the xiphoid process with the needle directed inward, upward, and close to the chest wall. The needle is advanced with constant suction applied to the syringe. Echocardiography may be used to guide the needle as agitated saline is injected through it. Once in place, the needle should be clamped next to the skin to prevent it from entering further than necessary and possibly puncturing the heart or injuring a coronary vessel. ECG monitoring is essential for detecting arrhythmias produced when the myocardium is touched or punctured. As a rule, right atrial pressure and pulmonary artery occlusion pressure (pulmonary capillary wedge pressure) are monitored. Fluid is withdrawn until intrapericardial pressure falls below right atrial pressure, usually to subatmospheric levels. If continued drainage is needed, a plastic catheter may be passed through the needle into the pericardium and the needle withdrawn. The catheter may be left in place for 2 to 4 days.
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Pain can usually be controlled with aspirin 325 to 650 mg po q 4 to 6 h or other NSAIDs (eg, ibuprofen 600 to 800 mg po q 6 to 8 h) for 1 to 4 days; duration of therapy varies, and patients should be treated until an effusion, if present, has resolved. Colchicine 1 mg/day, added to NSAIDs or given alone, is effective for the initial episode of pericarditis and helps prevent recurrences. The intensity of therapy is dictated by the patient's distress. Severe pain may require opioids and corticosteroids (eg, prednisone 60 to 80 mg po once/day for 1 wk, followed by rapid tapering of the dose). Corticosteroids are particularly useful in acute pericarditis due to uremia or a connective tissue disorder, but tuberculous and pyogenic pericarditis should be excluded before corticosteroid therapy is initiated. Intrapericardial instillation of triamcinolone (300 mg/m2) avoids systemic adverse effects and is highly effective. Anticoagulants are usually contraindicated in acute pericarditis because they may cause intrapericardial bleeding and even fatal tamponade; however, they can be given in early pericarditis complicating acute MI. Uncommonly, pericardial resection is required.
Infections are treated with specific antimicrobial drugs. Complete drainage is often necessary.
In postpericardiotomy syndrome, post-MI syndrome, or idiopathic pericarditis, antibiotics are not indicated. An NSAID at full doses may control pain and effusion. When required to control pain, fever, and effusion, prednisone 20 to 60 mg po once/day may be given for 3 to 4 days. If the response is satisfactory, the dose is gradually reduced, and the drug may be stopped in 7 to 14 days. But sometimes many months of treatment are needed.
For pericarditis due to rheumatic fever, another connective tissue disorder, or tumor, therapy is directed at the underlying process.
For pericardial effusion due to trauma, surgery is sometimes required to repair the injury and evacuate blood from the pericardium.
Pericarditis due to uremia may respond to increased frequency of hemodialysis, aspiration, or systemic or intrapericardial adrenal corticosteroids. Intrapericardial triamcinolone may be useful.
Chronic effusions are best treated by treating the cause, if known. Recurrent or persistent symptomatic effusions may be treated with balloon pericardiotomy, a surgical pericardial window, or sclerosing drugs (eg, tetracycline ). Recurrent effusion due to malignant tumor invasion may be treated with sclerosing drugs. Asymptomatic effusions of unknown cause may require only observation.
Congestion in chronic constrictive pericarditis may be alleviated with bed rest, salt restriction, and diuretics. Digoxin is indicated only if atrial arrhythmias or ventricular systolic dysfunction is present. Symptomatic constrictive pericarditis usually requires pericardial resection. However, patients with mild symptoms, heavy calcification, or extensive myocardial damage may be poor surgical candidates. The mortality rate for pericardial resection may approach 40% in New York Heart Association (NYHA) functional class IV patients. Patients who have constrictive pericarditis due to irradiation or a connective tissue disorder are especially likely to have severe myocardial damage and may not benefit from pericardial resection.
Last full review/revision September 2006 by Brian D. Hoit, MD
Content last modified September 2006
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