Diastolic Heart Failure: Restrictive
Cardiomyopathy, Constrictive Pericarditis,
and Cardiac Tamponade: Clinical and
Echocardiographic Evaluation
CRAIG R. ASHER, MD, and ALLAN L. KLEIN, MD
An understanding of the basic principles of diastolic function is important in order to recognize diseases that may result in diastolic dysfunction and diastolic heart failure. Although uncommon, restrictive cardiomyopathy, constrictive pericarditis, and cardiac tamponade are among the disorders that may affect primarily diastolic function with preservation of systolic function. Diastolic heart failure may manifest with chronic non-specific symptoms or may present with acute hemodynamic compromise. Echocardiogra-phy plays a vital role in the diagnosis of diastolic dysfunction and differentiation of these disease processes. It also provides a basis for clinical decisions regarding management and surgical referral. This review summarizes the clinical features, pathophysiology, and hemodynamic and echocardiographic signs of restrictive cardiomyopathy, constrictive pericarditis, and cardiac tamponade.
Key Words: Cardiac tamponade, Constrictive pericarditis, Diastolic dysfunction, Restric-tive cardiomyopathy
Diastolic dysfunction is defined as the requirement for elevated filling pressures to maintain cardiac output. Augmented filling pressures may result in excessive cardiac volume and right-sided or left-sided congestion, the syndrome of diastolic heart failure (1). Although diastolic dysfunction contrib-utes to heart failure in patients with abnormal sys-tolic function, it may occur in patients with normal function (2). Numerous disease processes affecting the myocardium and pericardium are associated with diastolic dysfunction and heart failure. The clinical manifestations of these conditions are di-verse, ranging from nonspecific, insidious symp-toms such as exertional dyspnea to pulmonary edema or sudden hemodynamic collapse.
The prevalence of diastolic heart failure is vari-ably reported depending on the age, diagnostic cri-teria, and referral patterns of the populations
stud-ied (2). Hypertension, coronary artery disease, valvular heart disease, and hypertrophic cardiomy-opathy are the predominant myocardial disorders that result in diastolic dysfunction with relatively preserved systolic function (3). Restrictive cardio-myopathies are less common causes of diastolic dysfunction because of myocardial storage or infil-tration. All of these myocardial conditions cause diastolic dysfunction largely by their effect on ven-tricular relaxation and compliance (4). Constrictive pericarditis and cardiac tamponade are pericardial disorders that impede ventricular filling by extrinsic constraint or limitation of chamber loading. Pericar-dial disorders may result in a spectrum of acute and chronic hemodynamic disturbance.
Distinguishing disorders that cause diastolic dys-function is important so that management can be tailored to the specific disease. This review dis-cusses the general principles of normal diastolic function and contrasts the abnormalities of diastolic dysfunction present with restrictive cardiomyopa-thy, constrictive pericarditis, and cardiac tampon-ade. The integral role of echocardiography in differ-entiating these diseases is highlighted.
Department of Cardiovascular Medicine, Section of Cardiovascular Imaging, Cleveland Clinic Foundation, Cleveland, Ohio
Address reprint requests to: Allan L. Klein, MD, Cleveland Clinic Founda-tion, Department of Cardiovascular Medicine, 9500 Euclid Avenue, Desk F15, Cleveland, OH 44195-0001.
Cardiology in Review
Volume 10, Number 4, pp. 218 –229
DIASTOLIC FUNCTION: PHYSIOLOGY
Diastolic filling of the left ventricle (LV) encom-passes the period of the cardiac cycle between aortic valve closure and mitral valve closure. Four distinct phases are distinguished: (1) isovolumic relaxation (between aortic valve closure and mitral valve open-ing), (2) rapid filling, (3) diastasis (slow fillopen-ing), and (4) atrial contraction (5). There are multiple physi-ologic determinants of diastolic function. The major myocardial factors that affect diastolic function in-clude LV myocardial relaxation, compliance, and left atrial function (5). Other parameters include heart rate, preload, afterload, atrioventricular con-duction, right ventricular (RV) function, intrathoracic pressure, viscoelastic properties, coronary engorge-ment, neurohormonal activation, and pericardial constraint (6). RV diastolic function is concordant with LV diastolic function in healthy people, al-though discordant filling and differing external in-teractions may occur in some disease states.
After LV contraction, diastole begins with the energy-dependent cellular process of ventricular relaxation, which extends into diastasis. LV relax-ation is best characterized by the time constant of relaxation (), which describes the rate of LV pres-sure decay in an exponential equation. Until re-cently, only invasive methods were available to estimate ()(7). Other, more dependent surrogate echocardiographic markers of relaxation include the isovolumic relaxation time (IVRT) and infor-mation obtained by color M-mode and Doppler tissue imaging. The IVRT characterizes the time when LV pressure declines and LV volume re-mains constant. When LV pressure drops below left atrial pressure, the mitral valve opens and the early rapid filling period begins.
During the early filling period (mitral E wave), there is a rapid increase in the LV chamber vol-ume, which contributes largely to the ventricular stroke volume (8). The amount of volume entering the LV cavity is influenced by many factors, in-cluding the pressure gradient between the pulmo-nary veins and LV, continued myocardial relax-ation, elastic recoil (ventricular suction), and stiffness properties of the myocardium (5). LV stiffness (or its reciprocal, compliance) character-izes the change in pressure within the chamber with an increase in volume and is dependent on the many inherent properties of myocardial con-tent, chamber dimension, and external constraints of the pericardium and thorax (5).
The left atrial and LV pressures are equalized during diastasis, resulting in slow or minimal
fill-ing. Diastasis is followed by atrial contraction (mi-tral A wave), which contributes variably to LV end-diastolic volume. Aside from the left atrium’s passive role as a conduit receptacle, it functions as a pump to regulate filling volume. When left atrial pressure is high at the end of diastole because of systolic heart disease, Frank-Starling mechanisms are activated (increased stretch, increased force of contraction), and atrial systole may contribute sig-nificantly to diastolic filling volume (9).
DIASTOLIC FUNCTION: ECHOCARDIOGRAPHY
The assessment of diastolic function has be-come an integral part of any echocardiographic study. Many causes of diastolic heart failure can be identified, including restrictive, hypertrophic, and ischemic cardiomyopathies and pericardial, valvular, and congenital heart disease. Diastolic filling patterns can be evaluated and stages of diastolic dysfunction determined that correlate with left-sided and right-sided filling pressures and disease-related prognosis (10 –13). Other techniques such as radionuclide angiography, magnetic resonance imaging, and cardiac cathe-terization are more time consuming, invasive, and tedious, and are generally used only as adjuncts to echocardiography.
Traditionally, the diastolic function exam fo-cuses on pulsed Doppler recordings of left-sided mitral inflow E and A waves and pulmonary vein systolic (S), diastolic (D), and atrial reversal (AR) waves and the corresponding right-sided tricus-pid inflow and hepatic vein flow waves (14). Measurements of deceleration and IVRT times and responses to physiologic maneuvers such as Valsalva provide more information. Using these parameters, 4 stages of diastolic dysfunction can be determined: (1) impaired relaxation, (2) pseudonormal stage, (3) restrictive, reversible stage, and (4) restrictive, irreversible function (15) (Fig. 1).
Newer technologies have provided supplemen-tal data to differentiate normal from pseudonor-mal patterns and to estimate left atrial and LV filling pressures more accurately (16) A color M-mode display shows a more precise spatial and temporal distribution of flow velocities propagat-ing across the mitral valve into the LV. The flow propagation velocity (vp) provides a relatively preload-independent determination of relaxation in various disease states and can be used in a regression equation with the mitral inflow E wave
to estimate pulmonary capillary wedge pressure (17). Doppler tissue imaging obtains the low ve-locity and high amplitude signals of the myocar-dium rather than the high velocity and low am-plitude blood signals (16). With this technique, spectral Doppler or color Doppler encoded veloc-ities can be recorded. Spectral Doppler myocar-dial velocities of the mitral annulus provide sys-tolic and diassys-tolic velocities (Em, early filling; Ea
or Am, atrial contraction) similar to the mitral inflow profiles. Studies have demonstrated that Em is relatively preload-independent in many disease states. As with vp, Em can be used to differentiate disease states such as restrictive car-diomyopathy and constrictive pericarditis and to assess LV filling pressures more accurately (18). Additionally, recent reports have emphasized the importance of assessing regional myocardial func-tion by Doppler echocardiographic strain rate im-aging (19).
RESTRICTIVE CARDIOMYOPATHY
As defined by the revised World Health Orga-nization Task Force, restrictive cardiomyopathy is a disease characterized by “restrictive filling and reduced diastolic volume of either or both ventri-cles with normal or near-normal systolic
func-tion.” (20) Despite this rigid definition requiring that restrictive hemodynamics are present, several studies have demonstrated early forms of these disorders with earlier stages of diastolic impair-ment. These diseases may be idiopathic or asso-ciated with specific systemic conditions and may be further characterized as myocardial (noninfil-trative, infil(noninfil-trative, and storage) or endomyodial types (21). The prognosis of restrictive car-diomyopathies is generally poor, except for those with reversible causes such as hemochromatosis. Cardiac amyloidosis is the most prevalent restric-tive cardiomyopathy, and the current literature addresses predominantly this specific disease (Fig. 2).
Because of the resistance to biventricular fill-ing, patients commonly develop a clinical profile related to congestive failure with fatigue, exercise intolerance, right-sided or left-sided heart failure, and atrial fibrillation (22,23). The clinical exami-nation correlates with these symptoms. An ele-vated jugular venous pressure with an x and prominent y descent (early-stage, M wave), y de-scent only (late-stage), and Kussmaul’s sign may be present, although pulsus paradoxus is always absent. Depending on the stage of disease, an S4 (early) or S3 (late) may be present (21). The elec-trocardiogram of amyloidosis typically shows a Figure 1. Stages of diastolic function as assessed by Doppler echocardiography mitral inflow, pulmonary venous flow, tissue Doppler, and color M-mode. Using an integrated approach with these 4 modalities, the stages of diastolic dysfunction can be determined. A, mitral A-wave velocity; Am, tissue Doppler atrial contraction wave; CMM-vp, color M-mode flow propagation velocity; D, pulmonary venous diastolic wave; E, mitral E-wave velocity; Em, tissue Doppler early filling wave; PV, pulmonary vein; S, pulmonary venous systolic wave; Sm, tissue Doppler systolic wave; TDE, tissue Doppler echocardiography; vp, color M-mode flow propagation velocity. Reprinted with permission from Garcia MJ, Thomas JD, Klein AL: New Doppler echocardiographic applications for the study of diastolic function. J Am Coll Cardiol 1998;32:865– 875.
large discordance between echocardiographic wall thickness and voltage (low voltage and in-creased wall thickness) (24).
Pathophysiology
As a result of myocardial or endocardial in-volvement such as amyloid infiltration, the ven-tricle is noncompliant or stiff and resists ventric-ular filling. Therefore, as the volume of the heart is increased, there is a steep rise in the pressure. Diastolic right-sided or left-sided heart failure may ensue (22).
Hemodynamic Signs
In the cardiac catheterization laboratory, inva-sive determination of operating stiffness may be demonstrated by pressure-volume curves, LV and RV hemodynamic tracings showing a dip and plateau or square root pattern (21). Other, less specific findings include a RV systolic pressure of greater than 50 mmHg with a RV end-diastolic pressure usually less than one third of the RV systolic pressure. Typically, the LV end-diastolic pressure is greater that the RV end-diastolic pres-sure (25).
Echocardiographic signs
Echocardiography is uniquely suited as a diag-nostic modality to detect the anatomic and func-tional abnormalities associated with restrictive cardiomyopathies. A combination of 2-dimen-sional imaging, M-mode, and Doppler informa-tion is important to identifying specific features of restrictive cardiomyopathy. Amyloidosis is pri-marily discussed here because it is the prototype of this class of diseases, and although endomyo-cardial disorders have very distinct features, they are less commonly encountered in this country.
Two-dimensional Imaging and M-mode
Increased wall thickness of the LV and often the RV is a hallmark of amyloidosis and almost all the myocardial disorders (26). Both ventricular cavi-ties are typically small with a decreased volume and large atria. The atrial septum and cardiac valves may also be thickened. A characteristic “granular sparkling” myocardial texture was de-scribed before harmonic and high frequency im-aging, but this may be a less sensitive and specific finding with current imaging modalities. A peri-cardial effusion may be present. The inferior vena cava is usually dilated and does not collapse with inspiration (plethoric), reflecting increased right atrial pressure.
Doppler Echocardiography
Diastolic dysfunction is a requirement for a restrictive cardiomyopathy, although not all pa-tients will have a restrictive diastolic filling pat-tern. In earlier stages of disease an impaired relax-ation pattern may be present before the onset of abnormal compliance. Determination of the sever-ity of diastolic impairment is important not only for diagnostic reasons; it has been demonstrated that the prognosis of patients with restrictive fill-ing patterns have a nearly fivefold higher mortal-ity than the nonrestrictive patterns (27).
The classic Doppler pattern of advanced cardiac amyloidosis is as follows: (28)
(1) Mitral inflow: large E wave and small A wave; E/A ratio greater than 2; short deceleration time (DT) less than 150 ms; short IVRT less than 60 ms; no significant change in mitral E wave, deceleration time, or IVRT with phases of respiration
(2) Pulmonary veins: small S wave; large D wave; Figure 2. Working classification of restrictive cardiomyopathy. Reprinted with permission from Leung D, Klein AL: Restrictive cardiomyopathy: diagnosis and prognostic implications. In Otto CM, ed:Practice of Clinical
S/D ratio less than 0.5; prominent AR (except with atrial systolic failure) width greater than mitral A wave and high amplitude; no signifi-cant respiratory variation of D wave
(3) Tricuspid inflow: similar to mitral inflow with an increased E/A ratio and short DT; with inspiration, there is further shortening of the DT and minimal change in E/A ratio (4) Hepatic veins: similar to pulmonary vein flow
with S/D ratio less than 0.5 and prominent atrial and ventricular reversals; with inspira-tion and expirainspira-tion, there is increased promi-nence of the reversal waves
Superior vena cava flows are similar to hepatic vein flows, and right and left heart patterns are concordant in most patients. Other findings in-clude the lack of respiratory variation of the tri-cuspid regurgitant jet with respiration and the presence of at least mild mitral and tricuspid regurgitation.
Doppler tissue imaging and color M-mode flow propagation have provided invaluable informa-tion for the differentiainforma-tion of restrictive cardiomy-opathy and constrictive pericarditis. Patients with restrictive cardiomyopathy have an abnormality of both relaxation and compliance, whereas those with constrictive pericarditis generally have nor-mal relaxation and impaired compliance because of pericardial impedance to filling. For this rea-son, patients with constrictive pericarditis gener-ally have a normal or fast color M-mode vpand a normal or increased Em, differing from patients with restrictive cardiomyopathy (16,18,29). A re-cent case report demonstrated that an exception to the rule of higher Em velocities with constrictive pericarditis may occur when pericardial calcifica-tion and tethering involve the annulus (30). In these cases, Doppler imaging of the apex and strain rate imaging may help confirm constriction. Differential Diagnosis
Differentiation of restrictive cardiomyopathy and constrictive pericarditis is essential because of the potential to relieve constrictive pericarditis effectively with surgical pericardial stripping (Ta-ble 1). It should be appreciated that certain con-ditions such as radiation of the heart may cause a mixed disease of constrictive pericarditis and re-strictive physiology.
Restrictive cardiomyopathy must also be distin-guished from other pathologic conditions that cause an increase in wall thickness because of hypertrophy. These diseases are caused by either primary hypertrophy (hypertrophic
cardiomyop-athy) or secondary hypertrophy (ie, aortic valve disease, hypertension).
CONSTRICTIVEPERICARDITIS
The majority of contemporary cases of nonidio-pathic constrictive pericarditis are caused by pre-vious cardiac surgery, radiation exposure, and chronic pericarditis with a myriad of etiologies (31). With the increasing rates of patients under-going cardiac surgery, the prevalence of constric-tive pericarditis may be increasing. Constricconstric-tive pericarditis can be surgically cured with pericar-dial stripping, with acceptable surgical mortality rates and symptomatic benefits in most patients (31). Therefore, clinicians must consider the diag-nosis among patients seeking treatment with symptoms that may be consistent with the condi-tion.
The clinical presentation of patients with con-strictive pericarditis may be nonspecific and in-dolent in the early stages. Symptoms may include fatigue or decreased exercise tolerance. In more advanced stages, patients may develop both left and right heart failure, with the latter often pre-dominating. Physical findings in advanced dis-ease reflect the signs of cardiac congestion (32). The hallmarks of physical diagnosis include an elevated jugular venous pressure with a promi-nent y descent (Friedreich’s sign) reflecting the predominance of filling in early diastole. Kuss-maul’s sign, an inspiratory increase in the jugular venous pressure, may be present but is not spe-cific for constrictive pericarditis (32). Findings specific to constrictive pericarditis include a peri-cardial knock (occurs after an opening snap and before an S3 in timing) because of cessation in diastolic filling and retraction of the apical im-pulse in systole. In very advanced cases, patients develop severe right heart failure.
In advanced cases, noninvasive diagnostic test-ing may be supportive of the diagnosis. The elec-trocardiogram may be low in voltage because of the pericardial encasement. The chest radiograph may show calcification of the pericardium and pleural effusions.
Pathophysiology
Most conditions that lead to constrictive pericar-ditis result in inflammation, fibrosis, adhesion, thickening, and calcification of the pericardium. Isolated constrictive pericarditis is characterized by an abnormality in compliance. Ventricular
compli-ance is impaired because of external interference to diastolic filling from a rigid pericardium. The myo-cardium is unaffected in isolated constrictive peri-carditis; therefore, systolic function and early dia-stolic filling are normal. Once ventricular diadia-stolic filling reaches the limitations of the pericardial re-straint, the pressure and volume in the cavity rise,
filling ceases, and congestion occurs (33). Because of the isolated encasement of the pericardium and not the systemic veins or lungs, there is a dissocia-tion between intrathoracic and intracardiac pres-sures with marked interventricular dependence, re-spiratory variation, and discordance in right and left heart filling (34).
Table 1. Differentiation between restrictive cardiomyopathy and constrictive pericarditis.
Evaluation Type Restrictive Cardiomyopathy Constrictive Pericarditis Physical Examination Kussmaul’s sign may be present Kussmaul’s sign usually present
Apical impulse may be prominent Apical impulse usually not palpable S3 (advanced disease), S4 (early disease) Pericardial knock may be present Regurgitant murmurs common Regurgitant murmurs uncommon Parodoxical pulse absent Parodoxical pulse rare
Electrocardiography Low voltage (especially in amyloidosis), pseudoinfarction, left-axis deviation, atrial fibrillation, conduction disturbances common
Low voltage (⬍50 percent)
Chest x-ray Absent calcification Calcification sometimes Echocardiography Small LV cavity with large atria
1wall thickness sometimes present (especially thickened interatrial septum in amyloidosis)
Normal wall thickness
Thickened cardiac valves (amyloidosis) Pericardial thickening seen
Granular sparking texture (amyloidosis) Prominent early diastolic filling with abrupt displacement of interventricular septum
Mitral inflow No resp variation of mitral inflow Inspiration⫽2mitral inflow E wave, IVRT, E wave, prolonged IVRT E/A ratio⬎2 Expiration⫽opposite changes
Short DT Short DT
Diastolic regurgitation Diastolic regurgitation Pulmonary vein Blunted S/D ratio (0.5), prominent &
prolonged AR
S/D ratio⫽1
No resp variation D wave Inspiration⫽2PV, S and D waves, Expiration⫽opposite changes
Tricuspid inflow Mild resp variation of tricuspid inflow E wave Inspiration⫽1tricuspid inflow E wave, 1TR peak velocity
E/A ratio⬎2 Expiration⫽opposite changes TR peak velocity no significant resp change Short DT
Short DT with inspiration Diastolic regurgitation Diastolic regurgitation
Hepatic vein Blunted S/D ratio, inspiratory1reversals Inspiration⫽Minimally1HV, S and D Expiration⫽2diastolic flow &1
reversals
Inferior vena cava Plethoric Plethoric
Color M-mode Slow flow propagation Rapid flow propagation (ⱖ100 cm/s) Mitral annular motion Low velocity early filling (⬍8 cm/s) High velocity early filling (ⱖ8 cm/s) Cardiac catheterization “Dip and plateau” ‘‘Dip and plateau’’
LVEDP often⬎5 mmHg greater than RVEDP, but may be identical
RVEDP and LVEDP usually equal
RV systolic pressure⬎50 mmHg Inspiration⫽1in RV systolic pressure2 in LV systolic pressure
RVEDP⬍one-third of RV systolic pressure Expiration⫽opposite changes Endomyocardial
biopsy
May reveal specific cause of restrictive cardiomyopathy
May be normal or show nonspecific myocyte hypertrophy or myocardial fibrosis
CT/MRT Pericardium usually normal Pericardium may be thickened Modified from Kushwaha SS, Fallon JT, Fuster V. N Engl J Med 1997; 336: 267–76, with permission in reference 43.
Hemodynamic Signs
Cardiac catheterization is usually reserved for unclear cases of constrictive pericarditis in which the diagnosis is uncertain. The classic feature of constrictive pericarditis is near equal-ization of chamber pressures between the left atrium, right atrium, LV and RV in end-diastole (33). Other hemodynamic findings include an elevated right atrial pressure, a pulmonary ar-tery pressure of less than 50 mmHg, and a RV diastolic pressure exceeding one third of the RV systolic pressure (25). Characteristic pressure tracings include the atrial waveform showing the W wave configuration with preserved x and prominent y descent and the simultaneous ven-tricular pressure waveform showing the dip and plateau configuration (33). Reciprocal changes with respiration can be observed, with the RV systolic pressure increasing with inspiration and the LV pressure decreasing.
Echocardiographic Signs
An integrated and dedicated echocardiographic examination including 2-dimensional imaging, M-mode, and Doppler are capable of diagnosing the anatomic and pathophysiologic features of constrictive pericarditis in most patients with sus-pected disease.
Two-dimensional Imaging and M-mode
The anatomic features of constrictive pericarditis may be recognized by 2-dimensional imaging (35). These include pericardial thickening, calcification, and localized tethering of the atrial or ventricular cavities (Fig. 3). A pericardial effusion may be present. The inferior vena cava is usually dilated (plethoric). The septal bounce is a classic feature of abnormal diastolic septal motion caused by abrupt termination of ventricular filling (35). LV and RV function are usually preserved in isolated cases. M-mode signs such as flattening of the LV free wall after early diastole are less well appreciated (36). Doppler Echocardiography
Elucidation of the pathophysiologic features of constrictive pericarditis requires a comprehensive dedicated Doppler examination. The hallmark of the examination is reciprocal respiratory variation of right and left heart flows caused by interven-tricular dependence (37). Because the heart is encased in a rigid shell, when the right heart fills during inspiration, the left heart filling is re-stricted by the shift of the septum to the left. The opposite changes occur with expiration.
The classic Doppler pattern of constrictive peri-carditis is as follows (37–39) (Fig. 4):
(1) Mitral inflow
Figure 3. Example of the utility of transesophageal echocardiography and magnetic resonance imaging for demonstrating the location and extent of pericardial thickening and calcification with constrictive pericarditis. Reprinted with
Inspiration: smaller E wave greater than A wave, longer IVRT and, usually shorter DT Expiration: larger E wave greater than A wave,
shorter IVRT and usually longer DT; E wave is typically increased more than 25% with expiration, and the IVRT increased more than 50% with inspiration
(2) Pulmonary veins
Inspiration: S and D waves near equal in size Expiration: larger S and D waves
(3) Tricuspid inflow: same pattern, with recipro-cal changes compared with mitral inflow; tri-cuspid E wave increase is typically more than 40% with inspiration
(4) Hepatic vein
Inspiration: S greater than D wave, with small AR and ventricular reversals
Expiration: S greater than D wave, with smaller or absent D wave and larger AR and ventric-ular reversals
Also described in constrictive pericarditis is an inspiratory increase in the tricuspid regurgitant jet velocity and duration of the signal (40). Supe-rior vena cava flow has been useful to distinguish respiratory changes caused by chronic obstructive lung disease from constrictive pericarditis, with the latter having less significant changes in sys-tolic forward flow during inspiration (41).
The Doppler findings of constrictive pericarditis with the hallmark of reciprocal respiratory variation contrast with the typical findings of restrictive car-diomyopathy. Doppler tissue imaging and color M-mode techniques provide more information for distinguishing these disorders. In addition, trans-esophageal echocardiography may be required for a more optimal Doppler examination and assessment of anatomic features of constriction.
Differential Diagnosis
There are limitations to the Doppler echocardi-ography differentiation of constrictive pericarditis and restrictive cardiomyopathy, and special clin-ical situations should be appreciated.
Particular attention must be paid to the loading conditions and respiratory effort when perform-ing a study. A respirometer is used to assess the timing of inspiration and expiration. The first beat after inspiration is measured because it is least likely to be affected by factors affecting the respi-ratory effort such as chronic obstructive lung dis-ease (34). The optimal examination is performed during a period of euvolemia, possibly requiring saline loading for hypovolemic patients and ma-neuvers or diuresis for hypervolemic patients (42).
Figure 4. Diagram of left (A) and right (B) ventricular inflow velocities and pulmonary (C) and hepatic (D) venous flows during different phases of respiration differentiating constrictive pericarditis and restrictive cardiomyopathy as assessed by echocardiography. Reprinted with permission from Klein AL, Cohen GI: Doppler echocardiographic assessment of constrictive pericarditis, cardiac amyloidosis, and cardiac tamponade. Cleve Clin J Med 1992;59:278 –290.
The many special situations make interpretation particularly challenging (43). Patients with irregular heart rhythms like atrial fibrillation may require ventricular pacing to equalize the R-R intervals. Conditions such as mixed restriction and constric-tion and effusive and constrictive states have fea-tures of both diseases. Other diseases that exaggerate the rate or force of breathing such as pulmonary embolism, obesity, and chronic obstructive lung dis-ease may cause reciprocal changes in right and left heart flows that must be differentiated from con-strictive pericarditis.
CARDIACTAMPONADE
Cardiac tamponade is a medical emergency caused by the inability of the heart to fill ade-quately to maintain cardiac output. Although the causes of pericardial effusions are numerous, in daily practice, most cases occur after cardiac sur-gery or with malignancy and any cause of acute or chronic pericarditis. Clinicians must be able to recognize and treat cardiac tamponade rapidly. Echocardiography is an essential modality to guide the choice of management. Patients may seek treatment with symptoms of low cardiac out-put or unheralded hemodynamic collapse. The medical or surgical history of the patient should provide ample clues to the potential for this event, because many events occur in patients after pro-cedures or with known effusions.
The bedside diagnosis of cardiac tamponade should be considered in a patient with elevated jugular veins, quiet heart sounds, tachycardia, and hypotension. The hallmark of the jugular ve-nous waveform is the loss of the y descent with a maintained x descent (33). A pulsus paradoxus may be present but is not specific for cardiac tamponade and may be absent in many disorders in which the LV or RV diastolic pressure is high or there is decompression of respiratory changes in pressures, as with an atrial septal defect (44). Other supportive noninvasive tests include an electrocardiogram with low voltage and electrical alternans, and a chest radiograph with cardiomeg-aly.
Pathophysiology
A small volume of fluid is present in a normal pericardial sac. When fluid accumulates because of injury inflammation or hemorrhage, the intra-pericardial volume and pressure rise proportion-ally with the compliance of the pericardial lining
and the intracardiac pressures. When intraperi-cardial pressure exceeds intracardiac pressure, there is interference of diastolic filling and subse-quent decreased cardiac output (44). With inspi-ration, intrathoracic pressure and pulmonary cap-illary wedge pressure decrease, whereas intracardiac pressure is unchanged because of the pericardial effusion. A decrease in gradient be-tween the pulmonary veins and LV results in a decreased mitral inflow E wave with inspiration and an increase in tricuspid E-wave flow (45). Reciprocal changes occur during expiration. Be-cause the cardiac chambers are in a finite space within the pericardium, there is equalization of pressures in all cardiac chambers.
Hemodynamic Signs
Right heart catheterization is an important tool to diagnose cardiac tamponade, particularly in patients in the intensive care unit setting, where physical diagnosis and echocardiography may have limitations. The typical hemodynamic signs include elevation of the central venous pressure with a prominent x descent and loss of the y descent and near equalization of right atrial, RV end-diastolic, pulmonary capillary wedge, and LV diastolic pressures (33). Tachycardia, a decreased stroke volume, cardiac output, and hypotension with a pulsus paradoxus may be present.
Echocardiographic Signs
In most patients with adequate image quality, echocardiography can rapidly and accurately make the diagnosis of cardiac tamponade. Causes of hemodynamic compromise other than cardiac tamponade may be excluded. The decision can also be made to evacuate the fluid via pericardio-centesis or surgery.
An integrated echocardiographic study incor-porating 2-dimensional imaging and Doppler must be performed to assess the presence of a pericardial effusion and the pathophysiologic consequences. In the intensive care unit setting, a transesophageal echocardiogram may be required if transthoracic imaging is suboptimal.
Two-dimensional Imaging and M-mode
A pericardial effusion is present in almost all cases of cardiac tamponade. Most pericardial ef-fusions appear as an echocardiography-free space that is localized or circumferential, free-flowing or organized. Scanning in and out of the plane may be required to separate the visceral and pari-etal pericardium in order to distinguish a
pericar-dial effusion from a pleural effusion. Another clue is the presence of fluid anterior to the descending aorta in the parasternal view. Even small effusions can cause tamponade, depending on their loca-tion and rate of accumulaloca-tion.
Cardiac chamber collapse is a critical feature of cardiac tamponade. The chambers with the lowest intracardiac pressure are most likely to be com-pressed. Right atrial collapse is the earliest sign of tamponade, occurring toward the end of ventric-ular end-diastole and extending into ventricventric-ular systole. Because the right atrium may often invert even in normal hearts with low right atrial pres-sure, the specificity of right atrial collapse may be low (46). Extension of collapse greater than 1/3 of the cardiac cycle increases the sensitivity of this finding to more than 90% (46). Although RV dia-stolic collapse is generally a more specific indica-tor of tamponade, the sensitivity can be reduced because of conditions that increase RV pressure (47). Left atrial and LV collapse are unusual and are observed generally with massive effusions or, in the case of left atrial collapse, loculated effu-sions.
A plethoric inferior vena cava (dilated with failure to collapse by more than 50%) is a highly sensitive sign of cardiac tamponade. This finding confirms high right atrial pressure, invariable with few exceptions in cardiac tamponade (48). Doppler Echocardiography
The Doppler examination confirms the patho-physiologic hemodynamic aberrations that occur during cardiac tamponade.
The classic Doppler pattern of cardiac tampon-ade is as follows: (37,45)
(1) Mitral inflow: for inspiration, E wave de-creases and IVRT inde-creases by more than 30% compared with expiration
(2) Tricuspid inflow: for inspiration, E wave in-creases more than 70% compared with expi-ration
(3) Pulmonary vein: for inspiration, D wave de-creases compared with expiration
(4) Hepatic vein: for inspiration, S is greater than D; for expiration, an absent or very dimin-ished D wave with prominent reversals Differential Diagnosis
Aside from the differentiation of pericardial from pleural effusions, other echocardiography-free spaces around the pericardium must be rec-ognized. These include pericardial fat pads (more often anterior and echocardiography-dense),
vas-cular structures (descending aorta, pseudoaneu-rysm, coronary sinus), other pericardial structures (cysts found in right cardiophrenic angle, hema-toma, or tumor), and noncardiac structures (hiatal hernia) (49).
In many situations, an incorrect diagnosis of cardiac tamponade is made based on the presence of confounding factors that affect respiratory vari-ation or chamber collapse (50). Clinical history and other echocardiographic findings are impor-tant in differentiating these conditions.
Conclusion
The clinical presentation of restrictive cardio-myopathy, constrictive pericarditis, and cardiac tamponade may vary vastly from chronic nonspe-cific symptoms to acute hemodynamic deteriora-tion. As diseases of diastolic dysfunction, there are common hemodynamic and echocardio-graphic features of these diseases. A comprehen-sive echocardiographic evaluation includes two-dimensional imaging and pulsed Doppler with a respirometer. Color M-mode and Doppler tissue imaging should be performed. Volume loading maneuvers or transesophageal echocardiography may also be required. Together, these techniques help to distinguish anatomic and pathophysio-logic findings specific to each process and pro-vide the basis for clinical decisions regarding management.
REFERENCES
1. European Study Group on Diastolic Heart Failure: How to diagnose diastolic heart failure. Eur Heart J 1998;19: 990 –1003.
A diagnostic criterion for diastolic heart failure is proposed. 2. Vasan RS, Benjamin EJ, Levy D: Prevalence, clinical
fea-tures and prognosis of diastolic heart failure: An epidemi-ologic perspective. J Am Coll Cardiol 1995;26:1565–1574. Summary of studies of patients with congestive heart failure determin-ing the prevalence of normal systolic function.
3. Grossman W: Diastolic dysfunction in congestive heart failure. N Engl J Med 1991;325:1557–1564.
Review of conditions and mechanisms of diseases associated with diastolic heart failure.
4. Stauffer JC, Gaasch WH: Recognition and treatment of left ventricular diastolic dysfunction. Prog Cardiovasc Dis 1990;32:319 –332.
Description of pathophysiologic factors responsible for increased chamber stiffness and impaired relaxation leading to increased dia-stolic pressures and diadia-stolic dysfunction.
5. Little WC, Downes TR: Clinical evaluation of left ventric-ular diastolic performance. Prog Cardiovasc Dis 1990;32: 273–290.
6. Gaasch WH, Blaustein AS, LeWinter MM: Heart failure and clinical disorders of left ventricular diastolic function. In Gaasch W, LeWinter M, eds:Left Ventricular Diastolic Dysfunction and Heart Failure. Lea & Febiger, Philadel-phia, 1994:245–258.
Review of nonmyocardial determinants of diastolic dysfunction. 7. Scalia GM, Greenberg NL, McCarthy PM, et al:
Noninva-sive assessment of the ventricular relaxation time constant () in humans by Doppler echocardiography. Circulation 1997;95:151–155.
Validation of a noninvasive measurement ofin humans as assessed by Doppler echocardiography.
8. Thomas JD, Weyman AE: Echocardiographic Doppler eval-uation of left ventricular diastolic function: Physics and physiology. Circulation 1991;84:977–990.
Detailed evaluation of the physical principles affecting diastolic func-tion.
9. Matsuda Y, Toma Y, Ogawa H, et al: Importance of left atrial function in patients with myocardial infarction. Cir-culation 1983;67:566 –571.
Study of left atrial function after myocardial infarction using pressure-volume loops to show the correlation between left atrial work and LV ejection fraction.
10. Cohen GI, Pietrolungo JF, Thomas JD, et al: A practical guide to assessment of ventricular diastolic function using Doppler echocardiography. J Am Coll Cardiol 1996;27: 1753–1760.
Practical correlation among clinical examination, physiology, and Doppler study.
11. Appleton CP, Galloway JM, Gonzalez MS, et al: Estimation of left ventricular filling pressures using two-dimensional and Doppler echocardiography in adult patients with car-diac disease: Additional value of analyzing left atrial size, left atrial ejection fraction and the difference in duration of pulmonary venous and mitral flow velocity at atrial con-traction. J Am Coll Cardiol 1993;22:1972–1982.
Correlation of LV filling pressures with Doppler mitral and pulmonary vein patterns and left atrial size and volumes.
12. Rossvoll O, Hatle LK: Pulmonary venous flow velocities recorded by transthoracic Doppler ultrasound: Relation to left ventricular diastolic pressures. J Am Coll Cardiol 1993;21:1687–1696.
Correlation of pulmonary venous flow reversal duration greater than mitral a wave duration with LV end-diastolic pressure greater than 15 mmHg.
13. Pozzoli M, Traversi E, Cioffi G, et al: Loading manipula-tions improve the prognostic value of Doppler evaluation of mitral flow in patients with chronic heart failure. Cir-culation 1997;95:1222–1230.
Demonstration of the additive importance of determining reversibility of restrictive flow patterns in assessing prognosis.
14. Appleton CP, Jensen JL, Hatle LK, et al: Doppler evalua-tion of left and right ventricular diastolic funcevalua-tion: A technical guide for obtaining optimal flow velocity record-ings. J Am Soc Echocardiogr 1997;10:271–292.
Technical guide reviewing performance and pitfalls of a comprehensive diastolic examination by Doppler echocardiography.
15. Nishimura RA, Tajik AJ: Evaluation of diastolic filling of left ventricle in health and disease: Doppler echocardiog-raphy is the clinician’s Rosetta stone. J Am Coll Cardiol 1997;30:8 –18.
A grading system for diastolic dysfunction is proposed in this review. 16. Garcia MJ, Thomas JD, Klein AL: New Doppler
echocar-diographic applications for the study of diastolic function. J Am Coll Cardiol 1998;32:865– 875.
Review of the additive information to the diastolic function examina-tion provided by color M-mode and Doppler tissue imaging. 17. Garcia MJ, Ares MA, Asher C, et al: An index of early left
ventricular filling that combined with pulsed Doppler peak E velocity may estimate capillary wedge pressure. J Am Coll Cardiol 1997;29:448 – 454.
Regression equation derived from color M-mode and mitral e-wave velocity that estimates pulmonary capillary wedge pressure. 18. Garcia MJ, Rodriguez L, Ares MA, et al: Differentiation of
constrictive pericarditis from restrictive cardiomyopathy: Assessment of left ventricular diastolic velocities in lon-gitudinal axis by Doppler tissue imaging. J Am Coll Car-diol 1996;27:108 –114.
Study illustrating the importance of E annular velocity to distinguish between constrictive pericarditis and restrictive cardiomyopathy. 19. Urheim S, Edvardsen T, Torp H, et al: Myocardial strain by
Doppler echocardiography: Validation of a new method to quantify regional myocardial function. Circulation 2000; 102:
1158 –1164.
Experimental study in dogs with hemodynamic validation of Doppler echocardiography determination of strain rate.
20. Richardson P, McKenna W, Bristow M, et al: Report of the 1995 World Health Organization/International Society and Federation of Cardiology Task Force on the Definition and Classification of Cardiomyopathies. Circulation 1996;93:841– 842.
Update of the 1980 report with revised definitions of cardiomyopa-thies.
21. Kushwaha SS, Fallon JT, Fuster V: Restrictive cardiomy-opathy. N Engl J Med 1997;336:267–276.
Review on restrictive cardiomyopathies with classification based on etiology.
22. Child JS, Perloff JK: The restrictive cardiomyopathies. Cardiol Clin 1988;6:289 –316.
Review of clinical manifestations of restrictive cardiomyopathies. 23. Benotti JR, Grossman W, Cohn PF: Clinical profile of
restrictive cardiomyopathy. Circulation 1980;61:1206 – 1212.
Early study reviewing the clinical manifestations of a small group of patients with restrictive cardiomyopathies.
24. Carroll JD, Gaasch WH, McAdam KP: Amyloid cardiomy-opathy: Characterization by a distinctive voltage/mass re-lation. Am J Cardiol 1982;49:9 –13.
Demonstration of the low voltage/high mass relationship in amyloid-osis.
25. Vaitkus PT, Kussmaul WG: Constrictive pericarditis ver-sus restrictive cardiomyopathy: A reappraisal and update of diagnostic criteria. Am Heart J 1991;122:1431–1441. Review of the diagnostic accuracy of hemodynamic findings in the cardiac catheterization laboratory.
26. Klein AL, Oh JK, Miller FA, et al: Two-dimensional and Doppler echocardiographic assessment of infiltrative car-diomyopathy. J Am Soc Echocardiogr 1988;1:48 –59. Description of the typical features of amyloidosis as seen on echocar-diogram.
27. Klein AL, Hatle LK, Taliercio CP, et al: Prognostic signif-icance of Doppler measures of diastolic function in cardiac amyloidosis: A Doppler echocardiography study. Circula-tion 1991;83:808 – 816.
Patients with mitral E-wave deceleration time less than 150 msec had a significantly reduced survival compared with those with time greater than 150 msec.
28. Klein AL, Hatle LK, Burstow DJ, et al: Doppler character-ization of left ventricular diastolic function in cardiac amyloidosis. J Am Coll Cardiol 1989;13:1017–1026.
Spectrum of diastolic filling abnormalities associated with amyloidosis that include early forms without restrictive physiology.
29. Rajagopalan N, Garcia MJ, Rodriguez L, et al:Comparison of new Doppler echocardiographic methods to differenti-ate constrictive pericardial heart disease and restrictive cardiomyopathy. Am J Cardiol 2001;87:86 –94.
A color M-mode flow propagation slope greater than 100 cm/s was an accurate method for predicting constrictive pericarditis.
30. Arnold MF, Voight JU, Kukulski T, et al: Does atrioven-tricular ring motion always distinguish constriction from restriction? A Doppler myocardial imaging study. J Am Soc Echocardiogr 2001;14:391–395.
Case report of 2 patients with constriction in whom Doppler tissue annular motion was inconsistent with the diagnosis.
31. Ling LH, Oh JK, Schaff HV, et al: Constrictive pericarditis in the modern era: Evolving clinical spectrum and impact on outcome after pericardiectomy. Circulation 1999;100: 1380 –1386.
Contemporary evaluation of the causes and outcomes of patients undergoing pericardiectomy.
32. Myers RB, Spodick DH: Constrictive pericarditis: Clinical and pathophysiologic characteristics. Am Heart J 1999; 138:219 –232.
Comprehensive review of studies characterizing features and patho-physiology of constrictive pericarditis.
33. Shabetai R, Fowler NO, Guntheroth WG: The hemodynam-ics of cardiac tamponade and constrictive pericarditis. Am J Cardiol 1970;26:480 – 489.
Review of the atrial and ventricular hemodynamic findings associated with pericardial diseases.
34. Hatle LK, Appleton CP, Popp RL: Differentiation of con-strictive pericarditis and recon-strictive cardiomyopathy by Doppler echocardiography. Circulation 1989;79:357–370. Echocardiography study demonstrating the importance of respiratory variation as a pathophysiologic hallmark of constrictive pericarditis. 35. Himelman RB, Lee E, Schiller NB: Septal bounce, vena
cava plethora, and pericardial adhesion: Informative two-dimensional echocardiographic signs in the diagnosis of pericardial constriction. J Am Soc Echocardiogr 1988;1: 333–340.
Accuracy of 2-dimensional echocardiographic criteria for constrictive pericarditis is evaluated.
36. Voelkel AG, Pietro DA, Folland ED, et al: Echocardio-graphic features of constrictive pericarditis. Circulation 1978;58:871– 875.
Flattening of the LV endocardium was the most consistent M-mode finding of constrictive pericarditis.
37. Klein AL, Cohen GI: Doppler echocardiographic assess-ment of constrictive pericarditis, cardiac amyloidosis, and cardiac tamponade. Cleve Clin J Med 1992;59:278 –290. Well illustrated review of the Doppler patterns characteristic of con-strictive and recon-strictive cardiomyopathies.
38. Klein AL, Cohen GI, Pietrolungo JF, et al: Differentiation of constrictive pericarditis from restrictive cardiomyopathy by Doppler transesophageal echocardiographic measure-ments of respiratory variations in pulmonary venous flow. J Am Coll Cardiol 1993;22:1935–1943.
Transesophageal echocardiography study determining the respiratory variation of mitral inflow and pulmonary venous flow consistent with constrictive pericarditis.
39. Oh JK, Hatle LK, Seward JB, et al: Diagnostic role of Doppler echocardiography in constrictive pericarditis. J Am Coll Cardiol 1994;23:154 –162.
Demonstration of the accuracy of a comprehensive diastology exami-nation for diagnosis of constrictive pericarditis.
40. Klodas E, Nishimura RA, Appleton CP, et al: Doppler evaluation of patients with constrictive pericarditis: Use of tricuspid regurgitation velocity curves to determine en-hanced ventricular interaction. J Am Coll Cardiol 1996;28: 652– 657.
Description of another useful diagnostic criterion for constrictive peri-carditis.
41. Boonyaratavej S, Oh JK, Tajik AJ, et al: Comparison of mitral inflow and superior vena cava Doppler velocities in chronic obstructive pulmonary disease and constrictive pericarditis. J Am Coll Cardiol 1998;32:2043–2048. Description of the marked inspiratory change in superior vena cava systolic flow velocity found with chronic obstructive lung disease but not with constrictive pericarditis.
42. Oh JK, Tajik AJ, Appleton CP, et al: Preload reduction to unmask the characteristic Doppler features of constrictive pericarditis: A new observation. Circulation 1997;95: 796 –799.
Report of a group of patients with constrictive pericarditis who did not exhibit typical respiratory variation until maneuvers to reduce preload were performed.
43. Klein AL, Asher CR: Diseases of the pericardium, restric-tive cardiomyopathy and diastolic dysfunction. In Topol EJ, ed:Textbook of Cardiovascular Medicine, edn 2. Lip-pincott-Raven Publishers, Philadelphia 2002, 596 – 646. Comprehensive discussion of constrictive pericarditis with attention to difficult diagnostic situations.
44. Spodick DH: The normal and diseased pericardium: Cur-rent concepts of pericardial physiology, diagnosis and treatment. J Am Coll Cardiol 1983;1:240 –251.
Description of the normal physiology of the pericardium and pathogen-esis of constrictive pericarditis and cardiac tamponade.
45. Appleton CP, Hatle LK, Popp RL: Cardiac tamponade and pericardial effusion: Respiratory variation in transvalvular flow velocities studied by Doppler echocardiography. J Am Coll Cardiol 1988;11:1020 –1030.
Study demonstrating the typical Doppler pattern of cardiac tamponade with reciprocal respiratory variation.
46. Gillam LA, Guyer DE, Gibson TC, et al: Hydrodynamic compression of the right atrium: A new echocardiographic sign of cardiac tamponade. Circulation 1983;68:294 –301. Prolonged right atrial inversion greater than 0.34 of the cardiac cycle was a highly accurate diagnostic criterion for cardiac tamponade. 47. Singh S, Wann LS, Schuchard GH, et al: Right ventricular
and right atrial collapse in patients with cardiac tampon-ade: A combined echocardiographic and hemodynamic study. Circulation 1984;70:966 –971.
Assessment of echocardiographic and hemodynamic findings related to chamber collapse with cardiac tamponade.
48. Himelman RB, Kircher B, Rockey DC, et al: Inferior vena cava plethora with blunted respiratory response: A sensi-tive echocardiographic sign of cardiac tamponade. J Am Coll Cardiol 1988;12:1470 –1477.
Dilated inferior vena cava with failure to collapse by more than 50% is found to be among the most sensitive findings of cardiac tamponade. 49. Spodick DH: Staying up-to-date on pericardial disease.
Patient Care October 2000;15:20 – 40.
Review of important pearls regarding the evaluation of pericardial disease.
50. Maxted WC, Segar DS: The utility of echocardiography in cardiac tamponade. ACC Curr J Rev 1997;6:90 –94. Good comparative review of studies testing the utility of echocardiog-raphy for assessment of cardiac tamponade.
