Figure 86-1. This drawing illustrates the pericardial attachments of the great vessels and pulmonary veins. The oblique sinus forms a blind cul-de-sac behind the left atrium, and the transverse sinus is a space between the aorta and pulmonary artery superiorly and the left and right atrium inferiorly.
While the electrocardiogram is nonspecific, it can be helpful in suggesting the diagnosis. In acute pericarditis the EKG classically shows diffuse ST elevations, and a low-voltage QRS is seen with a large pericardial effusion. The chest radiograph in a patient with a pericardial effusion shows an enlarged cardiac silhouette described as a water bottle. Pericardial calcification can be seen in chronic constrictive pericarditis secondary to tuberculosis.
9 Cardiac catheterization provides pressure tracings that help to distinguish cardiac tamponade, constriction, and restriction. Endomyocardial biopsy can also be useful in diagnosing restrictive cardiomyopathy.The echocardiogram is the most useful noninvasive test in evaluating pericardial disease. The echocardiogram can identify an effusion, pericardial thickening, or masses. By using Doppler and assessing changes in chamber size, echocardiogram is useful in assessing hemodynamics and can help differentiate tamponade, constriction, and restriction. It can also be used to help guide procedures like pericardiocentesis. Computed tomography and magnetic resonance imaging can identify pericardial masses and pericardial thickening or calcification.
Congenital absence of the pericardium is usually partial but can be complete. It is most common on the left side and is more frequent in males. Associated congenital cardiac defects include atrial septal defect, a bicuspid aortic valve, and pulmonary malformations. Defects on the right side can lead to cardiac herniation. Patients can present with chest pain, syncope, or death. The electrocardiogram can show a right bundle branch block. The pericardial defect can be appreciated on CT or MRI. The treatment of a partial defect is total pericardiectomy or patch closure with PTFE or bovine pericardium. Total pericardial absence is usually asymptomatic and is found incidentally.
Figure 86-2. The jugular venous pulse waveform.
Pericardial cysts are rare benign cysts that generally measure 1 to 15 cm in size. They are most commonly found at the right cardiophrenic angle and are asymptomatic. Patients may present with mediastinal compression and respiratory symptoms. The differential diagnosis includes a Morgagni hernia, lipoma, mediastinal tumor, or bronchogenic cyst. CT scans are used to confirm the location and relationship to surrounding structures. The cyst is excised if the patient is symptomatic, or the diagnosis is unclear.
Acute pericarditis is an inflammatory process that has involved the pericardium for less than 2 weeks (Table 86-1). Patients often present with a 3- to 7-day prodrome of low-grade fevers, malaise, and muscle aches. Acute pericarditis occurs in 5% of those who present to the emergency department with nonischemic chest pain10 and in 1% of those with ST elevation.11 It is important to distinguish pericarditis from the chest pain of an acute myocardial infarction. Acute pericarditis usually causes sharp, pleuritic pain that can last several days. The pain most commonly radiates to the trapezius ridge and is improved by leaning forward. Patients can present with shortness of breath, a nonproductive cough, and clear lung fields. The differential diagnosis also includes aortic dissection and pneumothorax. On physical examination, a friction rub may be heard and is sometimes intermittent. The classic friction rub has three components during systole, early diastolic filling, and atrial contraction.
Table 86-1 Causes of Pericarditis
12 The minimal workup should include an EKG, complete blood count, cultures, chemistry profile, and antibody titres for collagen diseases.The electrocardiogram is important in the diagnosis and classically shows diffuse ST elevations without Q waves or T-wave inversion. PR depression can also be seen. There is a four-stage progression in the changes seen on EKG with diffuse ST elevations followed by normalization of ST segments with flattening of T waves. The EKG then evolves with T-wave inversions prior to normalization of the EKG. Pericarditis and associated myocarditis can cause elevations in creatinine kinase and troponin I.
Idiopathic and Viral Pericarditis
Idiopathic causes of pericarditis are the second most common after neoplastic disease. The majority are likely viral although routine testing is not usually performed. A virus is only identified in 15% to 20% of cases with the most common being Coxsackievirus, echovirus, adenovirus, influenza, and cytomegalovirus. Patients present with chest pain, malaise, and fever and often have an elevated erythrocyte sedimentation rate. The episode is self-limited in 70% to 90% of cases.10 Initial treatment is with nonsteroidal anti-inflammatory drugs (NSAIDs). There is a 15% to 30% relapse rate at which point specific causes such as autoimmune disorders should be investigated.10,13 A repeat course of NSAIDs, colchicine, or steroids is generally successful. Pericardiectomy is recommended if the patient unresponsive to medical treatment or constriction develops.
Acquired Immunodeficiency Syndrome
A pericardial effusion develops in up to 20% of patients with HIV and is usually a poor prognostic sign.14 This may be partly due to a generalized capillary leak syndrome as well as increased cytokine expression seen in the more advanced stages of HIV. Other contributing factors include tubercular and mycobacterial infections, lymphoma, Kaposi’s, or congestive heart failure. The majority are idiopathic and do not require further therapy if asymptomatic. Symptomatic effusions are drained.
Tuberculous pericarditis occurs in 1% to 8% of patients.15 In immunocompromised patients infection by Mycobacterium avium or Mycobacterium intracellulare can lead to pericarditis. The incidence of tuberculous pericarditis has decreased although it continues to be a significant issue in immunocompromised patients, particularly HIV patients in Africa. Patients present with fever, night sweats, cough, dyspnea, and weight loss. While infection usually results from hematogenous spread, it can also extend directly from lymph nodes or through lymphatics. Pericardial changes occur in four stages including fibrinous, effusive, fibrous, and constrictive fibrous stages. Making the diagnosis from pericardial fluid alone is rare. Pericardial biopsy with acid fast staining provides the diagnosis 80% to 90% of the time. Treatment includes multidrug antitubercular therapy and pericardiocentesis. Steroids have not been shown to be beneficial for mortality or progression to constriction but leads to a faster resolution of symptoms and reaccumulation.16 If patients present with late constriction, pericardiectomy may be required.
Bacteria can be introduced into the pericardial space by direct injury, pneumonia, extension from head and neck infections, or hematogenous and lymphatic spread. Patients present with chest pain, fever, and leukocytosis. The most common organisms in adults are staphylococcus, pneumococcus, and streptococcus. Purulent pericarditis can evolve rapidly into tamponade and can be confused with septic shock. Fungal infections are less common, but immunocompromised patients and drug addicts are at greater risk. Pericardial fluid in purulent pericarditis has low glucose, high protein, and elevated LDH and neutrophils. An air–fluid level may be seen on chest radiograph with gas-producing organisms. Treatment includes antibiotics and drainage. Surgical drainage may be needed for thick fluid or refractory effusions. The prognosis for purulent pericarditis is poor with a survival of 30%.10,17
Fifty percent of patients with untreated renal disease develop pericarditis. The incidence is decreased to approximately 20% in patients on hemodialysis. The exact cause is unknown but is not directly related to the BUN or creatinine. Other possible etiologies include hypercalcemia, viral infection, and autoimmune disease. Chest pain is usually less common, and the large effusions accumulate gradually. Treatment includes more intensive dialysis, NSAIDs, and steroids. The fluid is generally bloody and care should be taken in heparinizing these patients for dialysis. If patients develop tamponade or the effusion is unresponsive, pericardiocentesis or surgical drainage is performed.
Vasculitis, Connective Tissue Disease, and Drugs
Pericarditis can result from a variety of vasculitic and connective tissue diseases including rheumatoid arthritis, Wegener granulomatosis, rheumatic fever, lupus, scleroderma, Reiter syndrome, Behcet disease, dermatomyositis, polyarteritis nodosa, dermatomyositis, sarcoidosis, and amyloidosis. Treatment includes management of the underlying disease process and NSAIDs. Pericardiocentesis is performed if necessary. Several medications can also lead to pericarditis including warfarin, hydralazine, isoniazid, procainamide, phenytoin, dantroline, cromolyn, and methysergide.
Dressler and Postpericardiotomy Syndrome
Pericarditis can occur following acute myocardial infarction in 3% to 5%.18 Pericarditis can develop early in the first 1 to 3 days particularly with transmural infarction. Forty percent of large Q-wave infarctions cause pericardial inflammation although the incidence is decreasing with the use of thrombolytics and early revascularization. Patients are usually asymptomatic and are found to have a pericardial rub on examination although they can present with pleuritic chest pain. Treatment is usually with NSAIDs. Steroids can prevent conversion of infarcted myocardium to scar leading to greater thinning and risk of rupture.19,20
Patients can also present with pericarditis 1 week to a few months after a myocardial infarction with a friction rub, typical EKG changes, and chest pain although the incidence has decreased with increased revascularization. Pericardial inflammation is thought to be from an autoimmune reaction to myocardial cells.20 Similar symptoms can also occur after cardiac surgery, blunt trauma, and pacemaker placement. Patients can develop a pericardial effusion and even tamponade. Treatment includes NSAIDs and colchicine for 2 to 3 weeks and occasionally steroids. The syndrome is usually self-limited.
Pericarditis can result from mediastinal and thoracic radiation for cancer including lymphoma and breast carcinoma and is related to the dosage delivered. With modern techniques, the incidence is 2% but can be as high as 20% if the entire pericardium is treated. Patients may develop chest pain and fever.20 Symptoms are usually self-limited, and tamponade is rare. Delayed symptoms can develop years later and can result in pericardial constriction. Due to the history of malignancy, the etiology can be confused with a malignant effusion. If pericardial constriction develops, the treatment is pericardiectomy although the mortality is higher than for other etiologies.
PERICARDIAL EFFUSION AND TAMPONADE
Any of the etiologies mentioned above for pericarditis can also lead to a pericardial effusion. Other causes include blunt or penetrating trauma, retrograde bleeding from an aortic dissection, and a transudative effusion from congestive heart failure. Effusions due to a bacterial or fungal infection, HIV, or malignancy have a higher incidence of progressing to tamponade. Twenty percent of large symptomatic effusions of unknown cause are due to an undiagnosed cancer.21
Patients may present with dyspnea, tachycardia, and diaphoresis. The three classic signs of Beck triad are hypotension, jugular venous distension, and muffled heart sounds although each may be absent in patients with tamponade.23 Symptoms can be confused with right heart failure and pulmonary embolus. The jugular waveform changes characteristically with loss of the y descent.24 Since the total heart volume is fixed in tamponade, blood only enters the heart when blood leaves. The y descent represents opening of the tricuspid valve and is lost since no blood is ejected from the heart. Pulsus paradoxus is also noted with a fall in the systolic blood pressure of greater than 10 mm Hg with inspiration. Pulsus paradoxus is absent in left ventricular dysfunction, atrial septal defect, positive-pressure ventilation, aortic insufficiency, and regional tamponade. The EKG shows variation in the morphology of every other QRS complex, or electrical alternans, due to swinging of the heart in the pericardial effusion (Fig. 86-3). Chest radiograph shows an enlarged, rounded cardiac silhouette, and the pericardial fat pad sign is seen when the pericardial fat is separated from the heart by the effusion.
Echocardiography is the most useful test in diagnosing pericardial effusion and tamponade. Signs of tamponade include early diastolic right ventricular and right atrial collapse (Fig. 86-4) and distension of the cava that does not diminish with inspiration. Doppler is useful in evaluating blood flow and shows exaggerated respiratory variation with an increase with inspiration on the right and decrease on the left side of the heart. Echocardiography is also useful in identifying localized atrial compression which can lead to tamponade with the other changes described above.
Figure 86-3. The 12-lead EKG shows electrical alternans with variation in the morphology of every other QRS complex in a patient with a large pericardial effusion. (From Joffe II, Jacobs LE, Kotler MN. Pericardial tamponade. Circulation 1996;94:2667, with permission.)