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CHAPTER SUMMARY AND CENTRAL ILLUSTRATION
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Chapter Summary
This chapter provides an overview of restrictive heart diseases, conditions characterized by diastolic dysfunction in the presence of elevated left ventricular filling pressures and limited increase in volume. The diastolic dysfunction may be observed in myocardial (restrictive cardiomyopathy [RCM] and phenocopies), endocardial/endomyocardial (fibrosis, elastosis), and pericardial (constriction, effusion) diseases (see Fuster and Hurst’s Central Illustration). Primary RCMs are rare myocardial diseases and are defined by 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, with significant atrial dilation. They carry a poor prognosis. Familial RCM are usually caused by mutations in genes encoding for sarcomeric proteins and intermediate filaments. Restrictive endomyocardial diseases include endomyocardial fibrosis of right, left, or both ventricles, frequently with involvement of valves, Hedinger syndrome of the right-sided heart valves in patients with neuroendocrine tumors and carcinoid syndrome, as well as endocardial fibroelastosis associated with congenital heart anomalies.
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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 (greater than or equal to 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 44–1). 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 previous pathology-based nosology of heart diseases into a precise, etiology-based classification of restrictive cardiac diseases (Chapter 40). This chapter illustrates the etiology, phenotypes, and management of these different diseases and separates cardiac and systemic diseases that share similar functional criteria but differ from each other, both etiologically and structurally. The gross inclusion of all myocardial diseases with altered diastolic function, regardless of causes and effects, in fact generates an imprecise nosology. For this reason, amyloid heart disease, for which new epidemiological, diagnostic and therapeutic data are now available, has been deemed worthy of a separate discussion.
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