Pericardial Disease

Step-By-Step Approach

Pericardial Effusion

▪ There are numerous causes for accumulation of fluid in the pericardial space (Table 10.1).
▪ A pericardial effusion may be asymptomatic or may be associated with pericarditis or with tamponade physiology.
▪ Pericarditis is a clinical diagnosis based on the triad of typical pericardial pain, a pericardial rub, and diffuse ST elevation on the electrocardiogram (ECG) (Fig. 10.1).
▪ Tamponade physiology is present when systemic blood pressure or cardiac output is reduced due to compression of the cardiac chambers by the pericardial fluid.

Key Points

□ In patients with pericarditis, the effusion ranges from absent to large in size.
□ The presence of a pericardial rub does not correlate with the size of the effusion.
□ In a patient with a large pericardial effusion and hypotension or a low cardiac output, tamponade physiology likely is present, even if other echocardiographic signs are not seen.

Step 1: Record Blood Pressure and Heart Rate

▪ The first step in echocardiographic evaluation of a patient with suspected pericardial disease is to measure and record blood pressure and heart rate (as for any echocardiographic examination).
▪ Pulsus paradoxus is a decline in the systolic blood pressure by more than 20 mm Hg with inspiration (Fig. 10.2).

Key Points

□ Hypotension and tachycardia are nonspecific but are seen in patients with tamponade physiology.
□ To measure pulsus paradoxus, the blood pressure cuff is deflated until the first Korotkoff sound is intermittently heard during expiration. The cuff is then slowly deflated until the Korotkoff sound is heard on every beat. The difference between these two pressures is the paradoxical pulse.
□ A physician should be present for the echocardiographic study when the patient is hemodynamically compromised (i.e., hypotension or significant tachycardia).

Step 2: Evaluate for the Presence of Pericardial Fluid

▪ An echo-free space adjacent to the heart is consistent with a pericardial effusion (Fig. 10.3).
▪ The pericardial sac extends completely around both the left ventricle (LV) and right ventricle (RV), from the apex to the base, and extends around the right atrium (RA) to the bases of the superior and inferior vena cava.

TABLE 10.1

Pericardial Disease: Clinical-Echocardiographic Correlates
	Clinical Presentation	Echocardiographic Findings
Constrictive pericarditis	Dyspnea on exertion and signs of venous congestion (elevated venous pressure, ascites, and edema)	• Ventricular septal shift • Hepatic vein diastolic flow reversals in expiration • Preserved or increased medial E′ velocity, often with medial E′ > lateral E′ velocities • Respiratory variation in mitral E velocities • Plethora of the IVC • Decreased lateral longitudinal strain, as compared to medial
Pericardial effusion	Variable depending on cause; often asymptomatic and incidentally discovered	• Pericardial effusion size ranges from trivial to very large; location is circumferential or loculated; fluid echo-brightness will vary with characteristics (transudative, exudative, or frankly bloody)
Tamponade	Variable; often nonspecific; including hypotension, tachycardia, elevated venous pressure, and pulsus paradoxus	• Chamber collapse • Plethora of the IVC • Respiratory variation in right- and left-heart filling and venous flow patterns
Acute pericarditis	Characteristic chest pain and ECG changes; pericardial friction rub on auscultation	• Effusion sometimes present, and helps secure the diagnosis • Ventricular regional wall motion abnormalities suggest associated myocarditis or an alternative diagnosis • Tamponade or constrictive physiology can occur

From Otto CM: The practice of clinical echocardiography, ed 6, Philadelphia, 2018, Elsevier.

Fig. 10.1 ECG in pericarditis.This 12-lead electrocardiogram (ECG) shows diffuse upsloping ST elevation and PR segment depression, consistent with pericarditis in this 42-year-old man with a 2-week history of persistent dull chest pain and a pericardial rub on physical examination.
Fig. 10.2 Pulsus paradoxus.This schematic shows that with inspiration, systolic blood pressure falls by at least 20 mm Hg when pulsus paradoxus is present. BP, Blood pressure; EXP, expiration; INSP, inspiration.
▪ The pericardial sac extends posterior to the left atrium (LA), between the pulmonary vein orifices (the oblique sinus of the pericardium), and there is a small cuff of pericardial space around the base of the great vessels (the transverse sinus) (Fig. 10.4).

Key Points

□ An isolated anterior, relatively echo-free space usually is due to the normal epicardial fat pad. With an effusion, the echo-free space usually is seen both anteriorly and posteriorly (Fig. 10.5)
Fig. 10.3 Pericardial effusion.An echo-free space consistent with a pericardial effusion is seen posterior to the LV in both the parasternal long-axis view (A) and in the short-axis view at the midventricular level (B). Ao, Aorta; DA, descending aorta; PE, pericardial effusion.
Fig. 10.4 Pericardial fluid in the oblique sinus of the pericardium.A small echo-free space is seen posterior to the LA (arrow) in this parasternal long-axis view. This is clearly a pericardial effusion, not pleural fluid, as it tracks anteriorly to the descending aorta. Ao, Aorta; DA, descending aorta; PE, pericardial effusion.
□ A pleural effusion is seen anterior to the descending thoracic aorta, whereas a pleural effusion extends posteriorly to the descending aorta (Fig. 10.6)
Fig. 10.5 Anterior adipose tissue.When an anterior echo-free space (long arrow) is seen, as in this parasternal long-axis view, without evidence for posterior effusion (short arrows), the most likely diagnosis is normal epicardial adipose tissue or a “fat pad.” This patient also has aortic valve stenosis. Ao, Aorta
□ Fluid adjacent to the RA in the apical 4-chamber view may be due to pericardial or pleural fluid. The specific diagnosis is based on evidence of pericardial or pleural fluid in other views.
□ If the pericardial fluid contains thrombus or fibrinous debris, the effusion may be echogenic instead of echolucent (Fig. 10.7).

Step 3: Evaluate the Distribution of Pericardial Fluid

▪ Effusions may be circumferential or loculated so that evaluation in multiple views from parasternal, apical, and subcostal windows is essential.
▪ Loculation of fluid due to adhesions often is seen after cardiac surgery or trauma or with malignant effusions.

Key Points

□ Loculated fluid may be missed unless multiple views are examined; sometimes transesophageal echocardiography (TEE) is needed to identify loculated fluid posterior to the LA (Fig. 10.8).
□ Loculated fluid occasionally may be mistaken for a normal cardiac chamber (e.g., when loculated fluid compresses the LA or RA).

Step 4: Estimate the Size of the Pericardial Effusion

▪ A small amount of pericardial fluid is normal, appearing as a trivial or absent effusion on echocardiography.
▪ The volume of an abnormal pericardial effusion ranges from 50 mL to more than 1 L.
▪ The size of the effusion is qualitatively graded as small, moderate, or large.

Key Points

□ A small effusion on two-dimensional (2D) imaging can be confirmed by the M-mode finding of flat motion of the parietal pericardium with systolic separation of the epicardium (Fig. 10.9).
□ There is no precise approach to estimation of pericardial fluid volume by echocardiography.
□ One useful approach is to consider the effusion small if the distance between the epicardium and pericardium is less than 0.5 cm, moderate if 0.5 to 2 cm, and large if more than 2 cm (Fig. 10.10).
□ With loculated effusions, size is described in a similar fashion along with the location of the fluid.
□ Evaluation from the subcostal view is especially important because this approach often is used for pericardiocentesis (Fig. 10.11).

Tamponade Physiology

▪ Pericardial pressure depends on both the volume and rate of accumulation of pericardial fluid.
▪ Tamponade physiology occurs when pericardial pressure exceeds intracardiac pressure.
▪ With tamponade physiology, cardiac output and blood pressure are reduced due to impaired cardiac filling due to compression of the cardiac chambers.
▪ Pulsus paradoxus is an excessive fall (>20 mm Hg) in systolic blood pressure with inspiration, due to the fall in cardiac output with inspiration.

Key Points

□ Tamponade physiology may occur with a rapidly accumulating moderate-sized effusion (e.g., with aortic dissection or trauma) but may not occur even with very large effusions if the rate of increase in size was gradual.
□ Thin-walled, low-pressure cardiac chambers (e.g., the RA) are compressed at lower pericardial pressures than thicker-walled chambers (e.g., the RV).
□ Cardiac compression is most evident during the phase of the cardiac cycle when the chamber pressure is low (e.g., systole for the atrial chambers, diastole for the RV).
□ With inspiration, intrathoracic pressure falls, resulting in increased filling of the right heart. If total cardiac volume is fixed (as with tamponade physiology), the increased filling of the right heart limits filling of the left heart, resulting in a lower forward stroke volume and blood pressure.
□ If the patient has a low cardiac output or hypotension and a large pericardial effusion is present, further echocardiographic evaluation is not needed; prompt therapy is more appropriate.

Step 1: Look for Right Atrium Systolic Collapse

▪ When intrapericardial pressure exceeds RA pressure, the RA free wall collapses in systole (Fig. 10.12).
Fig. 10.12 RA systolic collapse.The RA free wall is examined frame by frame in the apical 4-chamber plane using zoom mode and a narrow sector. This end-systolic frame shows persistent systolic compression (or collapse) of the RA free wall (arrow) consistent with tamponade physiology.
▪ RA free wall inversion for more than one-third of systole is sensitive and specific for the diagnosis of tamponade physiology.

Key Points

□ Brief systolic inversion of the RA free wall may be seen without tamponade physiology.
Fig. 10.13 RV diastolic collapse.Parasternal short-axis views in mid-diastole in a patient with a large pericardial effusion show RV diastolic collapse at the midventricular (A) and RV outflow tract (B) levels (arrows). The RV chamber is very small, with a convex indentation of the RV free wall by the pericardial effusion.
□ The RA free wall is best evaluated in the apical and subcostal 4-chamber views.
□ Zoom mode provides optimal image resolution; a narrow 2D sector improves frame rate.
□ Frame-by-frame analysis, to determine the number of frames with free wall inversion compared with the total frames in systole, improves the accuracy of this approach.

Step 2: Evaluate Right Ventricular Diastolic Collapse

▪ When intrapericardial pressure exceeds RV diastolic pressure, the RV free wall collapses in diastole (Fig. 10.13).
▪ RV diastolic collapse is less sensitive but more specific than brief RA systolic collapse for the diagnosis of pericardial tamponade.

Key Points

□ Frame-by-frame analysis or use of an M-mode cursor through the RV free wall may be helpful for evaluation of the timing of RV free wall motion.
□ RV diastolic collapse may be appreciated in parasternal long- and short-axis and in apical and subcostal 4-chamber views.
□ If the RV free wall is thickened due to hypertrophy or an infiltrative process, diastolic collapse may not occur even with elevated pericardial pressures.
□ RV diastolic collapse will not occur if RV diastolic pressure exceeds pericardial pressure, as can happen in severe pulmonary hypertension.

Step 3: Examine for Reciprocal Respiratory Changes in Right and Left Ventricular Volumes

▪ An effusion with tamponade physiology results in a fixed total cardiac volume.
▪ With a fixed total volume, the increase in right-sided filling with inspiration is matched by a reciprocal decrease in left-sided volumes.
▪ Conversely, with expiration there is a relative increase in left, compared with right, heart filling.

Key Points

□ The reciprocal changes in right- and left-filling with respiration are best seen on 2D imaging in a 4-chamber view.
□ With inspiration, the ventricular septum shifts to the left, followed by a shift toward the right with expiration.
□ An M-mode tracing of the septum from the parasternal window also may be helpful.

Step 4: Evaluate for Reciprocal Respiratory Changes in Right and Left Ventricular Filling Velocities

▪ Analogous to the changes in RV and LV volumes with respiration, the volume of inflow across the atrioventricular valves varies with respiration.
▪ With inspiration, there is an increase (>25%) in RV diastolic filling; with expiration, LV diastolic filling increases by >25% (Fig. 10.14).

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Tags: Echocardiography Review Guide

Apr 23, 2020 | Posted by admin in CARDIOLOGY | Comments Off

Key Points

Step 1: Record Blood Pressure and Heart Rate

Key Points

Step 2: Evaluate for the Presence of Pericardial Fluid

Key Points

Step 3: Evaluate the Distribution of Pericardial Fluid

Key Points

Step 4: Estimate the Size of the Pericardial Effusion

Key Points

Key Points

Step 1: Look for Right Atrium Systolic Collapse

Key Points

Step 2: Evaluate Right Ventricular Diastolic Collapse

Key Points

Step 3: Examine for Reciprocal Respiratory Changes in Right and Left Ventricular Volumes

Key Points

Step 4: Evaluate for Reciprocal Respiratory Changes in Right and Left Ventricular Filling Velocities

Related

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Thoracic Key

Fastest Thoracic Insight Engine

Pericardial Disease

Pericardial Disease

Step-By-Step Approach

Pericardial Effusion

Tamponade Physiology

Full access? Get Clinical Tree

Thoracic Key

Fastest Thoracic Insight Engine

Pericardial Disease

Step-By-Step Approach

Pericardial Effusion

Key Points

Step 1: Record Blood Pressure and Heart Rate

Key Points

Step 2: Evaluate for the Presence of Pericardial Fluid

Key Points

Step 3: Evaluate the Distribution of Pericardial Fluid

Key Points

Step 4: Estimate the Size of the Pericardial Effusion

Key Points

Tamponade Physiology

Key Points

Step 1: Look for Right Atrium Systolic Collapse

Key Points

Step 2: Evaluate Right Ventricular Diastolic Collapse

Key Points

Step 3: Examine for Reciprocal Respiratory Changes in Right and Left Ventricular Volumes

Key Points

Step 4: Evaluate for Reciprocal Respiratory Changes in Right and Left Ventricular Filling Velocities

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