Written by : Nathania Marliani Kristanti, MD, FIHA
Approximately one-half of all patients with heart failure (HF) have preserved ejection fraction (HFpEF), as many as 10% to 15% have a restrictive cardiomyopathy. The differential diagnosis of restrictive cardiomyopathy (RCM) includes constrictive pericarditis (CP), both share the same clinical presentation and common features in diagnostic imaging tests . Distinction of constrictive and restrictive hemodynamics remains a challenge, both results in impaired ventricular filling with clinical manifestations of predominantly right heart failure .
CP is a pathological condition with encasement of the heart by a thickened, fibrous, and sometimes calcified pericardium, with secondary abnormalities in chamber filling. Etiologic mechanisms have evolved with significant iatrogenic contribution from post-surgical inflammation and radiation therapy. Tuberculosis is the most frequent cause of pericardial disease in developing countries. Symptoms often arise insidiously, culminating in progressive signs and symptoms of predominantly right heart failure. Complete surgical removal of the pericardium can result in excellent symptomatic improvement. The prognosis is dependent upon the underlying etiology .
Restrictive cardiomyopathy is a primary disease of the myocardium, definition of RCM is on the basis of anatomic, histological, and physiological criteria. Namely the presence of abnormal LV diastolic filling associated with intracellular or interstitial infiltration and/or fibrosis in the absence of LV dilatation . Primary RCM is often idiopathic that may present in both children and adult, both familial and sporadic cases have been described . Secondary RCM are subclassified as infiltrative, noninfiltrative, and storage disorders. In infiltrative disorders, abnormal deposits occur in the interstitial space, whereas in storage disorders, deposits occur within the cell . Amyloidosis is the most common secondary cause of RCM.
Both CP and RCM have reduced LV chamber compliance. In RCM is caused by abnormal elastic properties of the myocardium and/or intercellular matrix, whereas in CP compliance is imposed by external pericardial constraint. Myocardial relaxation is impaired in RCM, but is typically normal in CP. Patients with CP exhibit exaggerated interventricular dependence and dissociation between intracardiac and intrathoracic pressures during respiration .
Echocardiography is the initial imaging test of choice in patients with signs and symptoms of constriction or restriction. 2D echocardiography can identify increased pericardial thickness although interpretation is often challenging. Adherence of the visceral and parietal pericardium can result in tethering, appreciated on the RV free wall from the subcostal or apical 4CH views. Assessment of ventricular septal motion on both M mode and 2D echo can provide insight into ventricular interdependence with inspiratory leftward motion of the septum and expiratory rightward shift (figure 1). Respirophasic ventricular septal shifting is usually the first echo clue to the diagnosis of CP because it is present in almost all patient with CP. Beyond the respirophasic motion, a septal “bounce”, also referred to as a “shudder” or “diastolic checking”, may be present with each beat in CP. Systemic venous congestion is present in both RCM and CP. Absence of a dilated inferior vena cava in patient without recent diuresis should call into question the diagnosis of hemodynamically significant CP or RCM .
Detailed Doppler hemodynamic evaluation is central to the diagnosis of both CP and RCM, and may be sufficient to confirm CP without hemodynamic catheterization in many patients. Mitral (and tricuspid) Doppler inflow patterns in both CP and RCM are early diastolic velocity (E-wave) predominant with a short deceleration time, reflecting the predominance of early rapid ventricular filling (figure 2). A critical difference is the presence of respiratory flow variation in CP, which is absent in RCM. Mitral inflow in CP demonstrate a respiratory variations of ³ 25%, with increased velocities during expiration (figure 3). This variation similarly seen in the pulmonary veins, with peak diastolic flow > 18% variation suggestive of CP. Tricuspid inflow Doppler demonstrates the reverse finding, namely a >40% increase in tricuspid velocity in the first beat after inspiration. Hepatic vein Doppler interrogation in CP shows decreased expiratory diastolic hepatic vein forward velocities with large expiratory diastolic reversal .
Mitral annular tissue Doppler assessment most useful to distinguish CP and RCM. In normal conditions the medial e’ velocity is lower than the lateral e’ velocity. As myocardial stiffening occurs and relaxation becomes delayed, e’ velocities become reduced, a hallmark of RCM. In CP, the mechanism of increased filling pressures is not at the level of the myocardium or due to reduced myocardial relaxation. Lateral cardiac motion is limited, due to pericardial constriction. Consequently, mitral annular e’ velocities are normal or paradoxically increased despite increased filling pressures, termed “annulus paradoxus”. In CP tethering of the LV free wall can result in reversal of the relationship between medial and lateral mitral annular tissue Doppler velocities, such that the medial e’ is higher (typically >7 cm/s) than lateral e’, a phenomenon referred to as “annulus reversus” . (figure 3)
Newer echocardiographic technique of speckle-tracking echocardiography (STE) and 3D echocardiography have supplemented the understanding of both CP and RCM. 3D echo dan provide additional information to pericardial visualization. Global longitudinal strain were significantly lower in patients with RCM, with some characteristic strain have been identified for various infiltrative cardiomyopathy .
Diagnosis of CP and RCM requires a multifaceted approach, with echocardiography as a cornerstone for diagnostic imaging. Both have overlapped clinical signs and symptoms but the management differs significantly. Recognition of the primary underlying disease is critical, given therapeutic differences.
Nathania Marliani Kristanti, MD, FIHA serves as cardiologist in Siloam Kebon Jeruk Hospital – Jakarta
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