Towards a New Classification of Cardiomyopathies

Abstract

Purpose of review: The aim of this paper is to briefly summarise the clinical approach to disease notation for cardiomyopathies and to highlight its limitations with respect to the integration of new knowledge about aetiology.

Recent findings: The paper uses the recently advocated concept of arrhythmogenic cardiomyopathy as an example of the limitations of current classification systems. At present, there is no single classification system that meets the needs of all potential users, whether they are basic scientists, clinicians, patients or families. The classical cardiomyopathy subtypes still have utility, but future disease notation needs to be modified to take into account the new and more complete phenotypes and aetiologies.

Keywords: Aetiology; Cardiomyopathy; Classification; Genetic; Molecular; Nosology.

Fig. 1

The MOGES nosology system for classifying cardiomyopathies. (M) Morphofunctional phenotype. This description is designed to contain additional information. These red flags are placed in parentheses after the notation of morphofunctional phenotype. (O) Organ/system involvement. This described involvement of other organs. (E) Aetiologic annotation provides information on specific disease genes and mutation, as well as a description of nongenetic causes of disease. (G) May denote a genetic disease, supporting family monitoring strategies. (S) Stage. This provides a simple description of functional limitation using existing scores such as the New York Heart Association class. Key: ACC, American College of Cardiology; AHA, American Heart Association; ARVC/D, arrhythmogenic right ventricular cardiomyopathy/dysplasia; DCM, dilated cardiomyopathy; ECG, electrocardiogram; ECHO, echocardiogram; HCM, hypertrophic cardiomyopathy; LVNC, left ventricular noncompaction; NYHA, New York Heart Association; RCM, restrictive cardiomyopathy. (Used with permission of Elsevier from: J Am Coll Cardiol. 2014;64:304–318. https://doi.org/10.1016/j.jacc.2014.05.027, permission conveyed through Copyright Clearance Center, Inc.) [••]

Fig. 2

Multiparametric approach to clinical notation. This figure shows how a systematic multiparametric approach to clinical phenotyping linked with targeted diagnostics including genetic testing can be used to create highly specific phenotypes that facilitate personalised treatment plans. In this worked example, the diagnosis transforms from a simplistic categorisation to a complex genetic disorder characterised by myocardial scar and a propensity to ventricular arrhythmia. The current approach to disease nomenclature based on a single descriptor (in this case arrhythmogenic LV cardiomyopathy or even more simply arrhythmogenic cardiomyopathy) is subjective and fails to convey anything about aetiology or treatment. Key: h=hour, VE=ventricular ectopics, DSP=desmoplakin