Pericardial Disorders


17
Pericardial Disorders


1. ACUTE PERICARDITIS


I. Causes of acute pericarditis


The four most common causes are:



  1. Viral or idiopathic pericarditis is the most common form of acute pericarditis (80–90%).
  2. Metastatic cancer, where a moderate or large effusion is usually seen.
  3. Connective tissue disease (lupus, rheumatoid arthritis, scleroderma).
  4. Infections (HIV, tuberculosis, bacterial, fungal, Lyme disease). In patients with HIV infection, pericarditis may be secondary to HIV itself or to a concomitant infection, particularly tuberculosis.

Other common causes of pericarditis, occurring in specific contexts:



  1. Uremia: an effusion is seen in >50% of patients with uremic pericarditis.
  2. Radiation: acute pericarditis, with or without effusion, may develop soon after radiation.
  3. Post-MI: pericarditis can occur early post-MI or late (Dressler syndrome).
  4. Post-cardiac surgery: pericarditis may occur early (in the first few days) or late (between 2 weeks and 2 months, similarly to Dressler syndrome and called post-pericardiotomy syndrome).
  5. Trauma (blunt or penetrating).

II. History and physical findings


A. Chest pain



  • Chest pain is sharp, pleuritic, usually not constricting. It usually has a rapid, sometimes abrupt, onset. It radiates to the trapezius ridge (a typical radiation of pericarditis) and/or the left arm.
  • Positional feature: pain is relieved by leaning forward and worsens with lying down, swallowing, or moving (including exertion).
  • Concomitant systemic findings may suggest a neoplastic, tuberculous, or autoimmune disease.

B. Friction rub



  • The rub is due to the friction of the inflamed visceral and parietal pericardial layers. It is heard during systole, early diastolic filling, and atrial contraction (three components). It is best heard at the left lower sternal border with the patient leaning forward. A sound with a single component is less specific for pericarditis as it may actually represent a murmur.
  • The rub is dynamic (it comes and goes), and all three components may not be evident all the time, hence the importance of frequent examinations when pericarditis is suspected.
  • A rub may be heard with pericardial effusion when concomitant inflammatory pericarditis is present.

III. ECG findings


(For the differential diagnosis of STEMI vs. pericarditis, see Chapter 31)


A. Diffuse concave ST elevation in all leads except aVR and V1


The axis of the subepicardial injury being the axis of the heart (~ + 45°), the ST elevation is most prominent in lead II and in the anterolateral leads, while the ST segment is often depressed in lead aVR, and sometimes V1 (and occasionally V2, III, or aVL, which are close to orthogonal to +45°).1


The ST segment is elevated at some point in >90% of patients, but normalizes in 1–5 days, often within 7 days. Thus, the ECG of pericarditis can look normal within a few days, at the time the patient presents.


The return of ST segment to baseline is followed, sometimes, by T-wave inversion that may last weeks or months. T wave may become biphasic before ST normalization, mimicking ischemia.


B. PR depression


The PR segment is depressed in 82% of patients, and this may be the earliest change. It is seen in all leads except lead aVR, where reciprocal PR elevation is always seen. While it commonly coexists with ST elevation, it can be an isolated change in ~25% of patients.


ST elevation and PR depression are mainly seen in idiopathic pericarditis, post-cardiac surgery pericarditis, and traumatic and hemorrhagic pericarditis.2 They are rarely seen in uremic, malignant, or tuberculous pericarditis, probably because of associated processes masking the pericarditis pattern.


C. Low QRS voltage and QRS alternans


If an effusion is present, the ECG may show low QRS voltage and sometimes QRS electrical alternans (which means an every-other-beat alternation of two different QRS morphologies). P- and T-wave alternans, in which two different P- and T-wave morphologies alternate, increases the likelihood of a pericardial effusion. Sinus tachycardia associated with a low QRS voltage or QRS alternans suggests tamponade.


IV. Echocardiography



  • Echocardiography is usually normal, and most often no effusion is appreciated (“dry” pericarditis). A small effusion is seen in 40% of pericarditis cases.
  • Moderate or large effusions are uncommon, seen in 5% of acute pericarditis cases. Idiopathic pericarditis is a less likely diagnosis in a patient with a moderate/large effusion but remains the most likely diagnosis; 25–50% of moderate or large pericardial effusions are idiopathic, whereas 80–90% of pericarditis cases with no or small effusions are idiopathic. An effusion increases the likelihood of a specific cause, such as malignancy, infection, or connective tissue disorder.
  • LV dysfunction, sometimes segmental, suggests an associated severe myocarditis.


V. Myopericarditis and perimyocarditis


Various degrees of myocardial inflammation are seen in patients with pericarditis. In fact, the ST-segment elevation implies subepicardial myocardial involvement rather than just pericardial involvement, the pericardium being electrically silent. Therefore, a troponin rise is common in pericarditis. Myopericarditis implies mild myocardial involvement, as evidenced by an elevated troponin, with a normal EF and no wall motion abnormalities. Myopericarditis has a good prognosis, with normalization of the ECG within 12 months and persistence of a normal EF.3–5 Troponin may be strikingly elevated (median 7 ng/ml, interquartile range 0.5–35 in one study).5 Unlike in ACS, this elevated troponin does not portend an increase in long-term complications. However, a reduction of the NSAID dose is considered (e.g., aspirin 500 mg TID), exercise is restricted for 4–6 weeks, and return to athletic activity is considered only after 6 months and after normalization of ECG and LV, and in the absence of arrhythmias on Holter and stress test.


When the process predominantly involves the myocardium, it is termed perimyocarditis or pure myocarditis and manifests as clinical HF or significant LV dysfunction, sometimes segmental. This predominant myocarditis may have ST changes of pericarditis or, more commonly, focal ST changes or Q waves mimicking STEMI. Coronary angiography is done to rule out ACS. Perimyocarditis with mild LV dysfunction (EF 40–50%) is associated with a good long-term prognosis and persistence of LV dysfunction in only 15% of patients.5 Perimyocarditis with severe LV dysfunction portends an altered long-term prognosis with persistent LV dysfunction in up to 60% of patients.


VI. Treatment


Pericarditis is a self-limiting disease with no complication or recurrence in >70% of patients.


A. Initial therapy



  1. A full anti-inflammatory dose of NSAID or aspirin is administered for 1–2 weeks. One dose is usually associated with a dramatic symptomatic effect. One regimen consists of the administration of a full-dose NSAID for a week, or better yet, until CRP normalizes (e.g., ibuprofen 600 mg TID, aspirin 750–1000 mg TID), followed by gradual tapering over 3 weeks, rather than abrupt cessation (e.g., taper ibuprofen by 200–400 mg per dose every week).3–6
  2. The systematic use of colchicine (for 3 months) as an adjunct to NSAID during the first episode of pericarditis strikingly reduces the recurrence of pericarditis by 70% (COPE trial).6 Colchicine therapy may thus be considered systematically and is given a class I in ESC guidelines (1 mg BID the first day, followed by 0.5 mg BID; a lower dose of 0.5 mg BID the first day followed by 0.5 mg once daily is given to patients weighing <70 kg).4
  3. In the absence of a response to NSAID, reconsider the possibility of specific etiologies. The NSAID dose may need to be increased, as inappropriately low doses may explain some therapeutic failures. Colchicine should be added. Glucocorticoids are generally avoided, as they increase the risk of recurrence, probably through the exacerbation of viral proliferation. Yet, glucocorticoids may be used in refractory cases or in autoimmune disorders (prednisone ~25–30 mg/d, with slow tapering every 1–2 weeks, even slower when reaching a dose<15 mg/d).
  4. Exercise restriction is warranted until clinical, ECG, and CRP resolution of acute pericarditis, more so in athletes (3 months). In myopericarditis or perimyocarditis, exercise restriction of 4–6 weeks is suggested in non-athletes, and at least 6 months in athletes. A normalization of the ECG, LV function, and CRP is required before return to athletic activity.3,4
  5. The following high-risk features increase the likelihood of a specific diagnosis (i.e., neoplastic, autoimmune, infectious) and the likelihood of complications, and therefore warrant hospitalization and a specific etiologic workup:3,4,7

    1. No response to 1 week of NSAID therapy
    2. Moderate or large effusion
    3. Subacute onset over days to weeks
    4. Fever >38 °C
    5. Clinical suspicion of a specific etiology


  • The specific etiologic workup consists of: HIV testing, PPD, ANA/rheumatoid factor, screening for specific cancers.
  • Also, myocarditis warrants hospitalization.

B. Recurrent pericarditis


Between 15% and 30% of patients with idiopathic or autoimmune pericarditis develop recurrent pericarditis within 20 months after the initial episode, and pericarditis may keep relapsing for several years.8 It is due to an autoimmune process initiated by the initial viral infection, although persistent or recurrent infection is possible. A recurrence within 6 weeks of the initial episode is usually considered a persistence of the initial pericarditis and is called “incessant” rather than recurrent pericarditis.


In the absence of high-risk features, recurrent pericarditis is usually idiopathic and does not warrant specific workup.3 Moreover, recurrent idiopathic pericarditis is usually milder than the initial pericarditis and is not associated with pericardial constriction; in fact, the risk of constrictive pericarditis is lower after a recurrence than after the initial episode of pericarditis.9 One-third of patients have pleuropericardial involvement during these recurrences.


For each recurrence, repeat the course of NSAID for a longer duration (2–4 weeks) with slow tapering over an additional 1 to several months, guided by CRP, and give a course of colchicine for ≥6 months.10 Avoid glucocorticoids, except for refractory pericarditis.


C. If an effusion is present, look for a specific etiology (see Section 3, Pericardial effusion, below) and perform serial echocardiographic exams. Echo is repeated during the hospital stay to ensure stability of the effusion, then serial outpatient echo exams are performed to ensure resolution of the effusion within a few months.


D. The occurrence of chronic constrictive pericarditis after acute idiopathic pericarditis is uncommon (<1%), and even less common after recurrent pericarditis. Approximately 9% of patients may have a transient constrictive physiology that results from the “rind” of acute inflammation rather than scar tissue and resolves in a few months (mean 2.1 months).3,11


2. TAMPONADE


I. Definition


Cardiac tamponade is defined as a pericardial effusion compressing one or more cardiac chambers and leading to hemodynamic compromise.


In tamponade, the pericardial fluid distends the pericardium and raises the intrapericardial pressure to ~10–25 mmHg, compressing one or more cardiac chambers. In typical, circumferential tamponade, this high intrapericardial pressure compresses all cardiac chambers in diastole until the pressure inside the four cardiac chambers equalizes with the intrapericardial pressure. This leads to equalization of the diastolic pressures of the four cardiac chambers. The diastolic pressure in the right heart is lower than the left heart, hence the right-sided chambers are compressed first and equalize with the intrapericardial pressure first. Also, since the right-sided chambers have thin walls, they tend to collapse when the intrapericardial pressure is equal to or larger than their intracavitary pressure.


In acute conditions, the pericardium cannot distend and its pressure rises markedly with small volume changes. This explains how tamponade develops with a small acute effusion (~200 ml). This also explains how the pericardium gets stretched in acute RV dilatation, leading to a “functional” constrictive pericarditis. Conversely, a slowly developing pericardial effusion induces tamponade only after a large volume of fluid has accumulated.


II. Pathophysiology and hemodynamics


The equalization of diastolic pressures is similar to what is observed in constrictive pericarditis. As opposed to constrictive pericarditis, however, the respiratory changes of intrathoracic pressure are transmitted to the cardiac chambers.12,13 This explains why RA pressure decreases with inspiration, and thus venous flow from outside the thorax to the RA increases during inspiration (jugular venous pressure decreases, explaining the absence of Kussmaul’s sign). Left-sided flow does not increase because both pulmonary veins and LV are exposed to the negative intrathoracic pressure. The increased venous flow to the right cavities makes the RV “push” against the LV in diastole, rather than “push” against the pericardium, since the high pericardial pressure prevents that (ventricular interdependence). This reduces LV filling in normal inspiration and explains the reduction of systolic arterial pressure by more than 10 mmHg with normal inspiration (pulsus paradoxus, which is an extreme form of RV–LV discordant filling).14


Also, as opposed to constrictive pericarditis, where the heart briefly expands in early diastole before getting constrained, the heart is compressed throughout all diastole in tamponade, including early diastole. Thus, there is no deep Y on the RA tracing and no diastolic dip on the RV tracing. There is a deep X in early systole as the RV annulus moves down and stretches out the compressed RA.14


In summary, tamponade is characterized by the following three hemodynamic findings:



  1. Elevation and equalization of diastolic pressures of the four cardiac chambers, similarly to constrictive pericarditis: CVP = PCWP = diastolic PA pressure = RVEDP = LVEDP. This equalization of diastolic pressures may also be seen in severe RV failure that creates a functional pericardial constriction.
  2. Elevated RA pressure with a deep X descent (mainly during inspiration), and a flat Y descent. The elevated RA pressure is equalized with the intrapericardial pressure on simultaneous RA–pericardial recording, particularly in expiration (Figure 17.1).
  3. While the systolic aortic pressure is initially normal or even elevated as a result of the adrenergic release, pulsus paradoxus is present and pulse pressure is abnormal early on. On any arterial or aortic tracing, pulsus paradoxus means that systolic pressure decreases >10 mmHg with normal inspiration. In addition, the arterial waveform is narrow and the pulse pressure is reduced (arterial tracing is “short” and narrow) (Figure 17.2).
Schematic illustration of simultaneous pericardial and RA pressures are recorded in tamponade, before pericardiocentesis.

Figure 17.1 Simultaneous pericardial and RA pressures are recorded in tamponade, before pericardiocentesis. The RA and pericardial pressures are elevated and equalized (~20 mmHg); this defines tamponade. The two tracings are actually superimposed, particularly in expiration; the pericardial pressure falls a bit more than the RA pressure in inspiration. Furthermore, X descent is seen, but Y descent is flat (mnemonic: Flat Y Tamponade = FYT).

Schematic illustration of pulsus paradoxus.

Figure 17.2 Pulsus paradoxus. Note the drop of systolic and pulse pressure during normal inspiration (arrows). The arterial waveform also becomes narrower.


III. Diagnosis: tamponade is a clinical diagnosis, not an echocardiographic diagnosis


Tamponade is diagnosed when a large pericardial effusion is associated with hemodynamic compromise, i.e., any one of the following clinical findings:



  1. Elevated JVP.
  2. Pulsus paradoxus, which is a decrease of SBP of >10 mmHg during normal, quiet inspiration. Example: when using the BP cuff, the Korotkoff sounds are heard intermittently at a systolic pressure of 150 mmHg and consistently (with each cardiac cycle) at a pressure of 120; therefore, the pulsus paradoxus is 30 mmHg. Avoid deep breathing during this measurement, as deep breathing is normally associated with an inspiratory drop of aortic pressure.

    The blood pressure is normal or elevated early on. Ultimately, the blood pressure declines. An increase in systolic pressure up to 150–210 mmHg and diastolic blood pressure up to 100–130 mmHg is frequent in tamponade and occurred in up to one-third of tamponade cases in one report, particularly in patients with a history of hypertension who are sensitive to the catecholamine surge.15 Hypertension does not imply preserved cardiac output; in fact, cardiac output is as low as in cases of normal arterial pressure, but increased peripheral vascular resistance preserves arterial pressure (pressure = flow × resistance). Patients with tamponade and hypertension have a reduction in blood pressure, reduction in systemic vascular resistance, and increase in cardiac output following pericardiocentesis.15


  3. Sinus tachycardia that attempts to compensate for the low stroke volume. Tachycardia may be absent in hypothyroidism and sometimes uremia (sinus node disease).
  4. Dyspnea/tachypnea/orthopnea with clear lungs. PCWP is increased up to 30 mmHg but the intracardiac and pulmonary venous volume is low, hence the lack of pulmonary edema and lack of significant hypoxemia despite severe dyspnea.

A decrease in heart sounds is characteristic of a large effusion but not necessarily tamponade. Even when an effusion is large, a friction rub may still be heard with inflammatory etiologies.


IV. Echocardiographic findings supporting the hemodynamic compromise of tamponade


(See also Chapter 32, Section VI)



  1. RV collapse in diastole. This is the most specific echo finding in tamponade. Sometimes, just an early diastolic indentation of the RVOT is seen on the parasternal long-axis M mode.
  2. RA collapse in early ventricular systole, when RA is emptiest. RA collapse lasting over one-third of the cardiac cycle is specific for tamponade. RA collapse is generally more sensitive but less specific for tamponade than RV collapse.
  3. Inspiratory changes of transmitral and transtricuspid flow. An inspiratory decrease of left-sided transmitral E flow by >25%, or an expiratory decrease of right-sided transtricuspid flow by >40%, during normal breathing, suggests tamponade (this is equivalent to the pulsus paradoxus). This is the earliest echo sign of tamponade but is not specific: it may be seen in any dyspnea with deep respiratory pressures.
  4. IVC dilatation with poor inspiratory collapse. IVC abnormality has a sensitivity of 97% and a specificity of 40% for tamponade. IVC is rarely normal in tamponade (the so-called low-pressure tamponade).

    Findings on hepatic venous Doppler: the flat Y descent on the RA tracing corresponds to a flat D wave on the hepatic venous Doppler. This contrasts with constriction, where both S and D are prominent. Yet, expiratory reversal of D is seen in both conditions; since it may be hard to discern S from D, constriction and tamponade grossly appear to have similar hepatic vein flow.


  5. Other findings

    • A rapid change in the effusion size suggests a threatened tamponade.
    • An abnormal septal motion may be seen as a result of ventricular interdependence like in constriction.
    • A swinging heart, i.e., a heart that changes position in a phasic manner, may be seen with a large effusion and corresponds to the electrical alternans seen on ECG. It does not necessarily imply tamponade.
    • Strands in the pericardial fluid imply inflammation or bleeding and can be seen with most effusions, except transudative effusions. A pericardial “rind” is diffuse pericardial thickening, forming a thick band; it increases the likelihood of inflammatory constriction (effusive-constrictive pericarditis).

    TEE, CT, or MRI may be performed when a loculated effusion with a regional tamponade is suspected.


V. Role of hemodynamic evaluation


The diagnosis of tamponade is established on clinical and echo grounds, and right heart catheterization is not usually necessary. However, if a Swan catheter is in place (e.g., post cardiac surgery), the following findings suggest tamponade: (i) an elevated CVP that approximates PCWP and PA diastolic pressure; (ii) a flat Y descent on RA tracing.


Also, right heart catheterization may be performed before and particularly after pericardiocentesis to document the hemodynamic improvement. Pericardial pressure is measured before drainage, in which case it is elevated (>0 mmHg) and equal to the RA pressure. Normalization of the pericardial pressure (to ≤0 mmHg) and the RA pressure must be documented after drainage. In fact, the normal pericardial pressure is ≤0 mmHg. The lack of full hemodynamic improvement suggests effusive–constrictive pericarditis.


VI. Special circumstances: low-pressure tamponade, tamponade with absent pulsus paradoxus, regional tamponade


A. Low-pressure tamponade


In patients who are hypovolemic, compression of intracardiac chambers (i.e., tamponade), particularly right-sided chambers, may occur at a lower intrapericardial pressure of 6–12 mmHg. In this case, there will be equalization of intrapericardial pressure and RA pressure at 6–12 mmHg. Thus, tamponade with pulsus paradoxus or hypotension occurs with a high-normal or only mildly increased RA pressure and jugular venous pressure.14 Were it not for hypovolemia and the low right-sided filling pressure, this pericardial effusion would not yet be hemodynamically significant. Fluid administration may correct the pulsus paradoxus; however, excessive fluid administration may sometimes increase the right-sided volume, which further stretches the already distended pericardium and elevates its pressure, leading to a full-blown tamponade picture.16,17 That is why fluids are helpful in hypovolemic patients with tamponade but may harm euvolemic or hypervolemic patients. In order to maintain a proper transmural pressure of the cardiac chambers, it is important to maintain a higher level of intracardiac pressure without excessive volume resuscitation (transmural pressure = intracavitary pressure minus pericardial pressure). Ultimately, patients with a low-pressure tamponade require pericardiocentesis since even at 6–12 mmHg, the intrapericardial pressure is at a steep portion of the pressure–volume relationship and is liable to rise with any change in pericardial volume (Figure 17.3).

Schematic illustration of the normal pericardial pressure is negative and reaches 0 mmHg at end-expiration.

Figure 17.3 The normal pericardial pressure is negative and reaches 0 mmHg at end-expiration (–10 to 0 mmHg). (a) Tamponade occurs when the pericardial pressure exceeds the pressure of a cardiac chamber (e.g., RV), thus compressing it and making it equalize with it. Typically, both ventricles get constrained by the pericardial shell, such that their pressure rises and equalizes with the pericardial pressure. They expand at the expense of each other (arrows). (b) Even before the RV gets compressed by the pericardial pressure, the transmural pressure of the RV and the RV expansion are affected (RV diastolic pressure = 10, pericardial pressure = 6 → the RV transmural, expansile pressure is reduced to +4). (c) Compliance curve of the pericardium, showing how the pericardial pressure rises quickly beyond a certain pressure point, even before tamponade occurs (threatened tamponade). This curve is more leftward in sudden acute effusions, wherein the pericardium is not compliant.


B. Underlying RV or LV failure and causes of absent pulsus paradoxus (and of attenuated septal and E variations)


While it is easy to induce tamponade in case of hypovolemia, it is difficult to induce tamponade physiology in patients with severely increased right-sided or left-sided diastolic pressure.14 In fact, it is harder for the pericardial pressure to compress both ventricles, and tamponade develops when pericardial pressure equilibrates with the lower-pressure ventricle. Moreover, the respiratory variation in venous return does not significantly change the cardiac output and the systolic pressure of the failing ventricle (flat portion of the Frank–Starling curve). The latter two conditions, that is, the lack of biventricular compression (and therefore lack of interdependence) and the lack of respiratory variation in ventricular output explain the lack of pulsus paradoxus. This situation may be seen in patients with cor pulmonale and in patients with end-stage renal disease and underlying left heart failure.


In addition, pulsus paradoxus may not be seen in: (1) ASD, where the increase in right-sided flow during inspiration is balanced by an increase in right-to-left shunt or reduction in left-to-right shunt, leading to less ventricular interdependence; (2) local tamponade (e.g., localized compression of one ventricle or atrium by a clot after cardiac surgery, leading to a localized increase in pressure); (3) AI, where the diastolic regurgitant flow damps down respiratory fluctuations of flow. In addition, pulsus paradoxus is difficult to detect in case of an irregular rhythm such as atrial fibrillation.


C. Regional tamponade


This occurs when only one cardiac chamber, a pulmonary vein, or the SVC or IVC is compressed by a loculated effusion (e.g., anterior loculation compressing the RV or RA, posterior loculation compressing the LV or LA). Since there is no uniform compression of the four chambers, there is no equalization of diastolic pressures and no ventricular interdependence/pulsus paradoxus. There is increased pressure of the compressed chamber, e.g., increased RA pressure or PCWP, and hypotension, which in the right context suggest tamponade (e.g., after cardiac surgery). However, loculation can also produce classic tamponade, presumably by tightening the uninvolved pericardium.


TEE or cardiac CT or MRI should be performed when a regional tamponade is suspected.


D. COPD and other causes of pulsus paradoxus and RV–LV respiratory discordance


Because of large intrathoracic pressure swings, COPD, asthma, morbid obesity, or positive-pressure ventilation may lead to discordance in RV and LV filling and pulsus paradoxus.


VII. Effusive–constrictive pericarditis


Some patients have a pericardial effusion with the hemodynamics of tamponade, i.e., pulsus paradoxus with elevated and equalized right- and left-sided filling pressures. However, upon drainage of the pericardial fluid, the hemodynamic compromise does not fully resolve. RV and LV diastolic pressures remain equalized, RA pressure remains elevated (or RA pressure declines by <50%), and the pericardial pressure may remain high. A flat RA Y descent (tamponade) may become deep (constriction) after drainage of the pericardial fluid. Effusive–constrictive pericarditis is an effusion that occurs on a background of constrictive pericarditis. In patients with a non-compliant pericardium, tamponade may occur with relatively little accumulation of fluid.


A relatively smaller pericardial effusion (eg, 1.5–2 cm) with disproprotionately severe hemodynamic compromise, such as severe JVP elevation, suggests effusive-constrictive pericarditis. Also, bloody effusions and fibrinous effusions with rind are frequently (up to 50%) constrictive.18 On echo, some features suggest a constrictive rather than a tamponade physiology (medial E’>lateral E’, pronounced respiratory septal shift).18


Effusive–constrictive pericarditis may be seen with pericarditis of any origin, particularly idiopathic, and is usually seen early in the disease course. In fact, up to 24% of constrictive pericarditis cases and 7–16% of tamponade cases have an effusive–constrictive pathophysiology.19 Effusive–constrictive pericarditis is often an inflammatory constrictive pericarditis that is transient in up to 90% of the cases and resolves with anti-inflammatory therapy, except when caused by radiation.19


VIII. Treatment of tamponade


Tamponade is initially temporized with fluid resuscitation. For example, administer one 500 ml fluid bolus at a time. Avoid excessive fluid resuscitation, as it may worsen pericardial distension and ventricular interdependence.


Similarly, avoid preload reduction (nitrates, diuretics).


Pericardiocentesis is urgently indicated, and the catheter is allowed to drain for ~3 days. Pericardiocentesis is often a definitive treatment of idiopathic effusions and late postoperative effusions, and at least a temporary treatment of malignant effusions.


A pericardial window is particularly useful for recurrences or loculated effusions (see below).


3. PERICARDIAL EFFUSION


A pericardial effusion without tamponade is not associated with hemodynamic compromise but may be associated with a dull ache and sometimes a pericarditic chest pain, particularly in the case of an inflammatory effusion. Dyspnea on exertion may occur and is, in fact, a manifestation of early tamponade. In order to be well tolerated and asymptomatic, a large effusion must be chronic. A large effusion is defined as an effusion larger than 2 cm (usually corresponds to 500 ml); moderate and small effusions are 1–2 cm and <1 cm wide, respectively. The effusion is measured as the summation of the anterior and posterior echo-free spaces in diastole. 20,21 This measurement is smaller in diastole than systole, but the diastolic measurement is what accounts for the diastolic compression and for the ability to tap (must be >2–3 cm to allow a safe pericardiocentesis).


I. Causes of a pericardial effusion with or without tamponade


Several series of moderate to large pericardial effusions have reported a lower prevalence of idiopathic causes compared with acute pericarditis. Similarly to acute pericarditis, the five most common causes of a moderate or large effusion are: 3,20,22,23



  1. Viral/idiopathic. Viral/idiopathic pericarditis rarely leads to a large effusion or tamponade, yet is still the most common cause of effusion and tamponade. Approximately 30–50% of large pericardial effusions are viral/idiopathic. While most HIV effusions are small, a large HIV effusion has a high rate of progression to tamponade (PRECIA study).24
  2. Neoplastic (lung, breast, lymphoma, melanoma). Malignancy causes 20–30% of pericardial effusions. Approximately 20% of patients with tamponade of unsuspected etiology are diagnosed with malignant effusion, this being their first cancer manifestation. As malignant effusions progress quickly, tamponade is a greater predictor of malignancy than an asymptomatic effusion.
  3. Metabolic (uremia or hypothyroidism).
  4. Connective tissue diseases.
  5. Specific bacterial infection or tuberculosis. Bacterial infections can spread from contiguous sites (pneumonia, empyema, ruptured valvular abscess, thoracic surgery) or hematogenously.

Other causes are seen in specific contexts:



  1. Post-cardiac surgery. The effusion may be an early hemorrhagic effusion, occurring in the first postoperative week. The effusion may also occur late, > 1 week postoperatively, secondarily to a post-pericardiotomy syndrome; it usually resolves within weeks.
  2. Post-MI. The effusion may occur early (resolves slowly over months) or late (along with Dressler syndrome). An early small effusion is often not worrisome, per se, and may accompany post-MI pericarditis or HF. Conversely, an early moderate or large effusion suggests a threatening free wall rupture.
  3. Radiation therapy. An early effusion (<1 year) may occur as part of an acute pericarditis and is sometimes recurrent. A late effusion (>1 year) is part of an effusive–constrictive pericarditis.
  4. HF or volume overload states (nephrotic syndrome, cirrhosis). Pericardial effusion is usually small or moderate in size, transudative, and only develops when right heart failure is present, as the pericardial veins drain in the coronary sinus. Isolated left heart failure does not lead to a pericardial effusion. A large pericardial effusion is rare but possible.21
  5. Hemorrhagic pericardial effusion, from a penetrating or blunt trauma, free wall rupture post-MI, complication of PCI (coronary perforation) or complication of device implantation (RA or RV rupture). Outside these traumatic/rupture contexts, a bloody effusion may be seen with a broad range of etiologies, such as malignant, viral, or infectious, with a prognosis that depends on the underlying etiology.
  6. Drugs (mainly minoxidil and drug-induced lupus: hydralazine, izoniazide).


II. Management of asymptomatic effusions and role of pericardiocentesis


A. General approach to a large asymptomatic effusion (Figure 17.4)


Two main concerns dictate the management of asymptomatic effusions: (i) etiology and (ii) risk of progression to tamponade. Up to 60% of patients with moderate/large pericardial effusions have a known medical condition, such as cancer, uremia, previous cardiac surgery, or connective tissue disease, which points toward a specific diagnosis.20 The following strategy is suggested:



  1. In the absence of a known medical condition that could cause a pericardial effusion, screen for some cancers, HIV/tuberculosis, and metabolic disorders using clinical findings and: CXR, mammography, chest CT; PPD, HIV; TSH, renal function, rheumatoid factor, ANA.
  2. Check markers of inflammation (CRP, ESR), which, if elevated without any cancer/infection/autoimmune disease, suggest a pericarditic process (viral/idiopathic).1
  3. If a malignant or bacterial (including tuberculous) etiology is suspected, pericardiocentesis is indicated both for its diagnostic and staging value and because of the high risk of progression to tamponade (“threatened tamponade”).3 Only 50% of effusions in cancer patients are due to malignant metastasis, the remaining being induced by viral or opportunistic infections, chemotherapy, obstruction of lymphatic drainage, or radiation; hence the additional diagnostic importance of pericardiocentesis in these patients.25

    If a hemorrhagic pericardial effusion is suspected (traumatic, iatrogenic), pericardiocentesis is indicated because of the imminent risk of tamponade.


    If an effusion is increasing in size, pericardiocentesis is warranted because of the risk of tamponade.


  4. Ensure the patient is truly asymptomatic. Even when the intrapericardial pressure is lower than the right-sided pressures, the RV or RA transmural pressure (RV pressure minus intrapericardial pressure) is reduced, which impairs RV outward expansion and filling. For example, if the pericardial pressure is 6 mmHg and the RV diastolic pressure is 10 mmHg, the RV does not collapse towards the LV, but it cannot appropriately expand and the cardiac output is already reduced. Also, at this point, pericardial pressure is at a steep slope and there is at least a threatened tamponade (Figure 17.3).26 In fact, one study has shown that almost all patients with a large asymptomatic effusion who underwent pericardiocentesis had a high intrapericardial pressure and a reduced RA transmural pressure.21,25 Thus, vague symptoms of fatigue or dyspnea on exertion often represent early hemodynamic compromise and warrant pericardiocentesis. The same applies to the echo signs of pre-tamponade.
  5. If all of the above is ruled out, the asymptomatic effusion is likely isolated, i.e., idiopathic. If the inflammatory markers are increased or if inflammatory signs are present (characteristic chest pain, friction rub, fever, or typical ECG changes), a pericarditic process is suspected and may be treated with NSAID and colchicine (class I indication).3,4,25 Echo follow-up is warranted to detect improvement of the effusion (or lack thereof), on a weekly basis initially.25 An autoimmune process is managed similarly.
  6. A chronic, large idiopathic effusion that persists for >3 months has a significant risk of progression to tamponade of 33%.3,4,21 Tamponade may develop unexpectedly and suddenly in patients who have had a chronic stable effusion for several years.21 The remaining patients remain stable; the effusion may regress at least partially, and a specific cause does not usually emerge with time.21 Thus, close echo surveillance is warranted. Alternatively, pericardial drainage may be considered for effusions persisting >3 months because of the 33% risk of tamponade.3,25

    A pericardiocentesis has a therapeutic but also a diagnostic value. The overall diagnostic yield of a pericardiocentesis is ~30%,27 but it is higher in neoplastic or bacterial effusions. The yield in neoplastic effusions is >50% (50%28 to 80%21,23). The pericardial fluid should be sent for cytology, cell count, bacterial and mycobacterial culture, and polymerase chain reaction of Mycobacterium tuberculosis (the latter is highly sensitive for tuberculous pericarditis).

Schematic illustration of general approach to a large, asymptomatic pericardial effusion.

Figure 17.4 General approach to a large, asymptomatic pericardial effusion.


B. Pericardiocentesis and open pericardiotomy (pericardial window)


Pericardiocentesis alone is often a definitive treatment of idiopathic pericardial effusion; in one series, recurrences only occurred in 8% of patients over long-term follow-up.3,29 However, another series suggested that recurrences are common and occur in 65% of patients with idiopathic large effusions.21 The duration of catheter drainage may explain the discrepancy. This recurrence rate is higher in malignant effusions, although pericardiocentesis may still be tried as a first-line therapy or as a temporizing measure in the unstable patient. Since fluid reaccumulation most commonly occurs in the first 48 hours after drainage, pericardiocentesis with prolonged catheter drainage is associated with an acceptable risk of recurrence of malignant effusions (<20%), particularly in view of the fact that patients with malignant effusions have a median survival of 3.5 months only.28 Hence, some authors recommend pericardiocentesis as a first and effective therapy in malignant effusions.25


A catheter should be left in the pericardial space at least until the drainage is <25 ml/24 hours. Prolonged catheter drainage for several days (e.g., 3–5 days), even after the drainage ceases, is preferred, as it provokes adherence that obliterates the pericardial space and reduces the risk of recurrence to <20–25%.25,28,29


Echo-guided pericardiocentesis may be performed through a left subxiphoid approach. The needle accesses the inferior (diaphragmatic) aspect of the pericardial space, not the posterior/lateral aspect. In a supine position, a free-flowing effusion accumulates on the posterior/lateral aspect; thus, the patient should be placed in an upright position to allow a free-flowing pericardial effusion to collect over the diaphragmatic aspect (Figures 17.5, 17.6). An effusion loculated at the posterior (lateral) aspect of the LV is not accessible; the same applies to an effusion loculated over the anterior aspect of the heart (RV free wall). An apical approach for the former and a parasternal approach for the latter may allow drainage. An apical approach is also simpler in obese patients, where it is difficult for the subxiphoid needle to cross the abdominal fat and get underneath the ribs. Pericardial pressure +/- right heart catheterization (RA pressure) are measured before but also after pericardiocentesis, to document the hemodynamic improvement.


Pericardiocentesis access sites:



  • Apical access: 5th or 6th intercostal space, >5 cm from the sternum; risk of pneumothorax. Advantages: short distance to the effusion and ability to use direct echo guidance.
  • Parasternal access: 5th or 6th left or right intercostal space, immediately adjacent to the sternum, <1 cm, to avoid injury to the internal mammary artery.
  • Left subxiphoid access: the needle enters the skin ~3–4 cm below the ribs, and is initially angled steeply to get below the ribs, then flattened into an angle that mimics the path of the echo probe (the path that was used to visualize the effusion).

Open pericardiotomy consists of cutting a “window” in the parietal pericardium to allow it to chronically drain in the mediastinum, which prevents recurrences. This is also known as a “pericardial window” and is usually performed through a subxiphoid access. Pericardial tissue and biopsies obtained through this procedure should be sent for analysis. A pericardial window is considered in the following cases: (i) recurrence of a large effusion, (ii) loculation, (iii) recurrence expected (malignant effusion), or (iv) a surgical biopsy is required for diagnosis (malignant effusion). Pericardiocentesis is still warranted for acute tamponade while awaiting surgery. After a pericardial window, the open parietal pericardium may adhere to the visceral pericardium or the sternum, in which case the effusion may recur (<5%). Even after a window procedure, prolonged drainage may reduce recurrences.


III. Note on postoperative pericardial effusions (after cardiac surgery)


Postoperative pericardial effusions may occur early, in the first postoperative week, in which case they are hemorrhagic with a high risk of tamponade; they usually require urgent drainage.


Outside these early bleeding complications, inflammatory postoperative effusions are common and typically appear or progress over the first 8–10 days, then tend to spontaneously regress thereafter (called late postoperative effusions). In fact, by postoperative day 8, ~40% of patients have a small effusion, ~20% have a moderate effusion, and 1% have a large effusion. By postoperative day 20–30, most of these effusions resolve or improve (by 5–10 mm on average), but ~10% of patients still have a moderate effusion.30–32 Large effusions have at least a 25% risk of progressing to tamponade within 30 days, while the risk with moderate effusions is ~10%; the risk may even be higher when these effusions persist longer.

Schematic illustration of heart surfaces in relation to the subxiphoid pericardiocentesis, in both supine and upright positions.

Figure 17.5 Heart surfaces in relation to the subxiphoid pericardiocentesis, in both supine and upright positions. On echo, the long-axis view and the apical four-chamber view show the posterior part of the effusion, not the one that will be accessed by pericardiocentesis. The subcostal view best shows the inferior part of the effusion, next to the inferior diaphragmatic wall of the RV (next to the liver).

Schematic illustration of various echo views showing the various heart surfaces in a patient with pericardial effusion.

Figure 17.6 Various echo views showing the various heart surfaces in a patient with pericardial effusion. The long-axis and four-chamber views show the posterolateral aspect of the effusion. The subcostal view shows the inferior aspect of the effusion next to the liver and is the one used to guide the left subxiphoid access.


These late effusions may be due to slow blood oozing in the pericardium or to a post-pericardiotomy syndrome, which is a pericardial and pleural inflammatory process occurring later than a week after surgery. In fact, half of these late effusions are hemorrhagic, while the other half are serosanguinous.


During cardiac surgery, the pericardium is opened and left open, which may seem protective against the development of a pericardial effusion. In reality, the edges of the cut pericardium may adhere to the sternum and create a new pericardial space, which is bound by the sternum anteriorly and the pericardium posterolaterally and superiorly. Moreover, the parietal pericardium may adhere to the visceral pericardium, thus closing the pericardial space. Hence, half of the postoperative pericardial effusions are circumferential, more so in case of tamponade, while the other half are loculated. Most loculated effusions are either anterior (meaning, over the RV) or posterolateral. Isolated loculation over the RA is less common (LA much less common).


Management

Moderate pericardial effusions warrant close echo follow-up (1–2 weeks) to document regression, especially if the patient is receiving anticoagulation. Small effusions may also require follow-up, especially if they develop early on (<7 days) or if the patient is receiving anticoagulants.30–33


Asymptomatic large pericardial effusions typically need to be drained, particularly if the patient is receiving anticoagulants.30,33 Early drainage or close surveillance followed by drainage (in the absence of a quick improvement within a week) are both acceptable strategies in patients not receiving anticoagulants.


Echo-guided pericardiocentesis is a safe and effective treatment of late postoperative effusions requiring drainage. In two major series, most postoperative effusions were drained percutaneously, with a low recurrence rate of only 4%.33 Subxiphoid pericardial window is another alternative, and is particularly useful for loculated effusions inaccessible percutaneously (posterior effusions), recurrent effusions, and possibly effusions occurring in patients receiving anticoagulants (higher recurrence risk).


NSAIDs have not been shown to significantly change the natural history of asymptomatic postoperative effusions (POPE trial), even though the mechanism of these effusions is thought to be inflammatory.31 Nonetheless, NSAIDs may be useful in patients with increased CRP.


IV. Note on uremic pericardial effusion


Two forms of renal pericarditis are seen. One form occurs in acute or advanced chronic renal failure not undergoing dialysis (classic uremic pericarditis), while the second form occurs in patients undergoing adequate chronic dialysis with normal BUN and creatinine (dialysis-associated pericarditis).


Uremic pericardial effusion usually resolves after several weeks of intensive hemodialysis (heparin should be used cautiously during dialysis); unless tamponade is present, watchful management is appropriate.2 The effusion occurring in patients adequately receiving chronic dialysis inconsistently responds to dialysis intensification. A pericardial window may be required.


4. CONSTRICTIVE PERICARDITIS


Constrictive pericarditis is due to pericardial scarring that takes years to develop, but in some instances it only takes a few months. The pericardium becomes a stiff “shell” that surrounds the right and left cardiac chambers and impairs their filling, leading to signs of right heart failure and symptoms of left heart failure. Both the visceral and parietal layers are fibrotic and adherent to the myocardium. A transient constrictive physiology without pericardial scarring may be seen after any pericardial inflammation (such as 9% of acute idiopathic pericarditis).34


I. Causes


The three most common causes of constrictive pericarditis are, in order of frequency: idiopathic, post-cardiac surgery, and post-mediastinal irradiation.35,36


Other, less common causes, are: autoimmune (especially rheumatoid arthritis), post-infectious, traumatic, malignant.

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Nov 27, 2022 | Posted by in CARDIOLOGY | Comments Off on Pericardial Disorders

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