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Restrictive physiology describes a pattern of ventricular filling in which increased myocardial stiffness causes a precipitous elevation of ventricular pressure matched by a limited increase in volume; the resultant diastolic dysfunction is characterized by a pattern of mitral inflow Doppler velocities with an increased ratio of early diastolic filling to atrial filling (≥ 2), decreased E-deceleration time (< 160 ms), and decreased isovolumetric relaxation time.
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Diastolic dysfunction occurs in several cardiac diseases with a range of etiologies.1 Restrictive physiology can be observed in diseases affecting endocardium, myocardium, and epipericardial layers/structures (Table 61–1). The recent development of advanced technologies for DNA sequencing, refined imaging techniques, and identification of novel biomarkers have contributed to unraveling the primary causes of many of these different diseases, facilitating more targeted treatments. These dynamic technologies will continue to develop and will transform the past pathology-based nosology of heart diseases into a precise, etiology-based classification of restrictive cardiac diseases (see Chap. 57). This chapter illustrates the etiology, phenotypes, and management of these different diseases. In this context, cardiac amyloidosis is described as a separate entity; it represents a pan-heart disease affecting all cardiac structures and a unique disease model of extracellular infiltration by amyloid fibrils.
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RESTRICTIVE CARDIOMYOPATHY
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According to the definition of the European Society of Cardiology (ESC), “Restrictive cardiomyopathies are defined as restrictive ventricular physiology in the presence of normal or reduced diastolic volumes of one or both ventricles, normal or reduced systolic volumes, and normal ventricular wall thickness.”2 According to the definition of the American Heart Association (AHA), “Primary restrictive non-hypertrophied cardiomyopathy is a rare form of heart muscle disease and a cause of heart failure (HF) that is characterized by normal or decreased volume of both ventricles associated with biatrial enlargement, normal LV (left ventricular) wall thickness and AV (atrioventricular) valves, impaired ventricular filling with restrictive physiology, and normal (or near normal) systolic function.”3 Both definitions emphasize restrictive ventricular physiology, normal or reduced volume of one or both ventricles, and normal wall thickness. AHA further stipulates the presence of atrial ...