CHAPTER SUMMARY AND CENTRAL ILLUSTRATION
This chapter reviews the evolving classification of cardiomyopathies over the last 65 years, which were first defined in 1957 as noncoronary cardiomyopathies or isolated noncoronary myocardial diseases (see Fuster and Hurst’s Central Illustration). In 2013, the World Heart Federation (WHF) endorsed a systematic classification referred to as MOGE(S), which combined two complementary concepts from the previous American Heart Association (AHA) and European Society of Cardiology (ESC) recommendations. The system of classification describes morphofunctional presentation (M), organ involvement (O), genetic basis (G), precise description of (genetic or acquired) etiology (E) and functional New York Heart Association (NYHA) class and American College of Cardiology (ACC)–AHA status (S). In the 2019 classification of cardiomyopathies in children, the AHA incorporated the elements of MOGE(S) in a hierarchy system based on the structural and functional phenotype with genetic and nongenetic causes as subcategories. Going forward, each new formula for reporting the classification will have to realize the need for short and rapid communication tools that can be universally adopted, but we must also recognize that the acceptance of every new proposal by the clinical community takes time. Any commitment of the clinical community has to go beyond the phenotype and include the cause as mandatory information, so that all cardiologists share a common diagnostic language.
As any classification is necessarily incomplete and acts as a bridge between complete ignorance and total understanding in any biological system, … further modification and changes are likely to occur.
— John Goodwin, London, 1982
eFig 40-01 Chapter 40: Classification of Cardiomyopathies
Clinical taxonomy aids understanding and facilitates appropriate categorization of diseases through the use of logical groups and hierarchies on the basis of predefined criteria that are useful for the diagnosis and management of human ailments. Disease classifications result in standardization of disease nomenclature. In the premolecular era, this process was driven by clinical phenotypes (eg, heart failure, cardiomyopathies, and arrhythmias) and pathology (eg, cancer). For etiologically heterogeneous diseases such as cardiomyopathies, the principles of classification have been historically based on morphofunctional characteristics shared by phenotypically similar disorders. Traditionally, the cardiomyopathies have been considered idiopathic diseases. In the last two decades, clinical and molecular genetics and advanced imaging have contributed to elucidate the etiology of cardiomyopathies, to the point that the term idiopathic is gradually becoming obsolete. Most cardiomyopathies have a genetic basis, and for many of those that are not heritable, the mechanisms are now known.
CLASSIFICATION OF CARDIOMYOPATHIES: A HISTORICAL PERSPECTIVE
Heart muscle disorders are relatively young diseases. In a famous editorial published in Heart in 1982, John F. Goodwin reviewed the 30-year history of cardiomyopathies,1 starting from the early 1950s, when Brigden published the St. Cyres lecture on “Uncommon Myocardial Diseases: The Non-coronary Cardiomyopathies.”2 The evolution from ...