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Diastolic Heart Failure: RestrictiveCardiomyopathy, Constrictive Pericarditis,and Cardiac Tamponade: Clinical andEchocardiographic EvaluationCRAIG R. ASHER, MD, and ALLAN L. KLEIN, MD
An understanding of the basic principles of diastolic function is important in order torecognize diseases that may result in diastolic dysfunction and diastolic heart failure.Although uncommon, restrictive cardiomyopathy, constrictive pericarditis, and cardiactamponade are among the disorders that may affect primarily diastolic function withpreservation 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 thesedisease processes. It also provides a basis for clinical decisions regarding managementand surgical referral. This review summarizes the clinical features, pathophysiology, andhemodynamic and echocardiographic signs of restrictive cardiomyopathy, constrictivepericarditis, and cardiac tamponade.
Key Words: Cardiac tamponade, Constrictive pericarditis, Diastolic dysfunction, Restric-tive cardiomyopathy
Diastolic dysfunction is defined as the requirementfor elevated filling pressures to maintain cardiacoutput. Augmented filling pressures may result inexcessive cardiac volume and right-sided or left-sided congestion, the syndrome of diastolic heartfailure (1). Although diastolic dysfunction contrib-utes to heart failure in patients with abnormal sys-tolic function, it may occur in patients with normalfunction (2). Numerous disease processes affectingthe myocardium and pericardium are associatedwith diastolic dysfunction and heart failure. Theclinical manifestations of these conditions are di-verse, ranging from nonspecific, insidious symp-toms such as exertional dyspnea to pulmonaryedema 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 disordersthat result in diastolic dysfunction with relativelypreserved systolic function (3). Restrictive cardio-myopathies are less common causes of diastolicdysfunction because of myocardial storage or infil-tration. All of these myocardial conditions causediastolic dysfunction largely by their effect on ven-tricular relaxation and compliance (4). Constrictivepericarditis and cardiac tamponade are pericardialdisorders that impede ventricular filling by extrinsicconstraint or limitation of chamber loading. Pericar-dial disorders may result in a spectrum of acute andchronic hemodynamic disturbance.
Distinguishing disorders that cause diastolic dys-function is important so that management can betailored to the specific disease. This review dis-cusses the general principles of normal diastolicfunction and contrasts the abnormalities of diastolicdysfunction 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 CardiovascularImaging, Cleveland Clinic Foundation, Cleveland, Ohio
Address reprint requests to: Allan L. Klein, MD, Cleveland Clinic Founda-tion, Department of Cardiovascular Medicine, 9500 Euclid Avenue, DeskF15, Cleveland, OH 44195-0001.
Cardiology in ReviewVolume 10, Number 4, pp. 218229Copyright 2002 Lippincott Williams & Wilkins
218 CARDIOLOGY IN REVIEW
DIASTOLIC FUNCTION: PHYSIOLOGY
Diastolic filling of the left ventricle (LV) encom-passes the period of the cardiac cycle between aorticvalve closure and mitral valve closure. Four distinctphases are distinguished: (1) isovolumic relaxation(between aortic valve closure and mitral valve open-ing), (2) rapid filling, (3) diastasis (slow filling), and(4) atrial contraction (5). There are multiple physi-ologic determinants of diastolic function. The majormyocardial factors that affect diastolic function in-clude LV myocardial relaxation, compliance, andleft atrial function (5). Other parameters includeheart rate, preload, afterload, atrioventricular con-duction, right ventricular (RV) function, intrathoracicpressure, viscoelastic properties, coronary engorge-ment, neurohormonal activation, and pericardialconstraint (6). RV diastolic function is concordantwith 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 theenergy-dependent cellular process of ventricularrelaxation, which extends into diastasis. LV relax-ation is best characterized by the time constant ofrelaxation (), which describes the rate of LV pres-sure decay in an exponential equation. Until re-cently, only invasive methods were available toestimate ()(7). Other, more dependent surrogateechocardiographic markers of relaxation includethe isovolumic relaxation time (IVRT) and infor-mation obtained by color M-mode and Dopplertissue imaging. The IVRT characterizes the timewhen LV pressure declines and LV volume re-mains constant. When LV pressure drops belowleft atrial pressure, the mitral valve opens and theearly 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 ventricularstroke volume (8). The amount of volume enteringthe 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), andstiffness properties of the myocardium (5). LVstiffness (or its reciprocal, compliance) character-izes the change in pressure within the chamberwith an increase in volume and is dependent onthe many inherent properties of myocardial con-tent, chamber dimension, and external constraintsof the pericardium and thorax (5).
The left atrial and LV pressures are equalizedduring 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 atriumspassive role as a conduit receptacle, it functions as apump to regulate filling volume. When left atrialpressure is high at the end of diastole because ofsystolic heart disease, Frank-Starling mechanismsare activated (increased stretch, increased force ofcontraction), 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 echocardiographicstudy. Many causes of diastolic heart failure canbe identified, including restrictive, hypertrophic,and ischemic cardiomyopathies and pericardial,valvular, and congenital heart disease. Diastolicfilling patterns can be evaluated and stages ofdiastolic dysfunction determined that correlatewith left-sided and right-sided filling pressuresand disease-related prognosis (1013). Othertechniques such as radionuclide angiography,magnetic resonance imaging, and cardiac cathe-terization are more time consuming, invasive, andtedious, and are generally used only as adjuncts toechocardiography.
Traditionally, the diastolic function exam fo-cuses on pulsed Doppler recordings of left-sidedmitral inflow E and A waves and pulmonary veinsystolic (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 timesand responses to physiologic maneuvers such asValsalva provide more information. Using theseparameters, 4 stages of diastolic dysfunction canbe determined: (1) impaired relaxation, (2)pseudonormal stage, (3) restrictive, reversiblestage, 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 LVfilling pressures more accurately (16) A color M-mode display shows a more precise spatial andtemporal distribution of flow velocities propagat-ing across the mitral valve into the LV. The flowpropagation velocity (vp) provides a relativelypreload-independent determination of relaxationin various disease states and can be used in aregression equation with the mitral inflow E wave
CARDIOLOGY IN REVIEW 219Volume 10, Number 4, 2002
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 diastolic velocities (Em, early filling; Eaor Am, atrial contraction) similar to the mitralinflow profiles. Studies have demonstrated thatEm is relatively preload-independent in manydisease states. As with vp, Em can be used todifferentiate disease states such as restrictive car-diomyopathy and constrictive pericarditis and toassess LV filling pressures more accurately (18).Additionally, recent reports have emphasized theimportance of assessing regional myocardial func-tion by Doppler echocardiographic strain rate im-aging (19).
As defined by the revised World Health Orga-nization Task Force, restrictive cardiomyopathy isa disease characterized by restrictive filling andreduced diastolic volume of either or both ventri-cles with normal or near-normal