Historical Evolution and Classification of Cardiomyopathy

Cardiomyopathies were originally understood as unique diseases of the heart muscle separate from the usual causes of heart dysfunction, such as hypertension, valvular disease, congenital defects, pericarditis, or coronary artery disease. Over the years, however, the definition has broadened. Today, cardiomyopathy refers to a wide and diverse group of conditions, all involving changes to the heart’s structure or function, many of which have a genetic basis. The modern era of study began in 1957, when British cardiologist Wallace Brigden first coined the term “cardiomyopathy (myocardiopathy).” His work marked the beginning of a more detailed categorization and understanding of heart muscle diseases. Brigden used the term to describe non-coronary heart muscle disorders, grouping them into five categories based on their cause: congenital, infectious, amyloid infiltration, collagen diseases, and an anatomic type known as endomyocardial fibrosis of unknown origin. Before Bridgen’s contribution, any unexplained disease of the heart muscle of non-valvular origin was labeled “chronic myocarditis.” That began to change in 1956, when Blankenhorn and Gall refined the terminology, using “myocarditis” strictly for inflammatory diseases of the heart muscle and “Myocardosis” for degenerative heart muscle diseases. In 1961, Goodwin and colleagues defined cardiomyopathies as subacute or chronic diseases of the cardiac muscle with unknown etiology. For the first time, they classified cardiomyopathies into three major types: 

• Congestive, which is now recognized as dilated cardiomyopathy
• Obliterative or constrictive, now recognized as restrictive cardiomyopathy
• Obstructive, now recognized as hypertrophic cardiomyopathy.

By 1968, the World Health Organization (WHO) had adopted the term “cardiomyopathy” and described it as heart muscle disease of unknown etiology characterized by heart failure and cardiomegaly. Oakley, in 1971, described cardiomyopathy as a myocardial disorder of unknown etiology. In that same year, John Goodwin proposed a new way of classifying these conditions. He suggested focusing only on primary cardiomyopathies and dropping the term “secondary cardiomyopathies,” instead grouping heart muscle disease based on the underlying disorder. However, this system proved complicated and still left many cases unclassified. Then, in 1972, Goodwin and Oakley reported cardiomyopathy as a myocardial disease of unknown cause and classified it based on functional pathology findings as previously categorized by Godwin in 1961. This classification was significant because it was the first to associate specific categories of cardiomyopathy with targeted treatment recommendations.

• For congestive (dilated) cardiomyopathy, Oakley and Goodwin suggested bed rest, digitalis, and diuretics as the core therapies.
• For hypertrophic cardiomyopathy, they recommended surgical removal or incision of the thickened septum when left ventricular outflow obstruction was present. This approach has demonstrated significant improvement of symptoms to date. 

In 1980, the World Health Organization (WHO)/International Society and Federation of Cardiology (ISFC) Task Force defined cardiomyopathy as “heart muscle diseases of unknown cause, following the poor knowledge of cardiac diseases at that time, and proposed a new cardiomyopathy classification: dilated, hypertrophic, restrictive, and unclassified cardiomyopathy (those that did not fit into these groups). The unclassified cardiomyopathies were described as latent cardiomyopathy with initial cardiac abnormalities and specific heart muscle diseases of known cause or associated with systemic diseases. Disorders such as systemic or pulmonary hypertension, coronary artery disease, valvular disease, or congenital defects were intentionally excluded. In 1982, Goodwin summarized the ongoing challenge by stating that “a classification serves to bridge the gap between ignorance and knowledge.” His words captured the evolving and often difficult journey toward understanding cardiomyopathies during that era.

The WHO/ISFC Task Force published a new classification system in 1996, reflecting an improved knowledge of how cardiomyopathy develops (they focused on the known dominant pathophysiology, etiology, and pathogenesis of the diseases). The Task Force defined cardiomyopathy as a disease of the heart muscle associated with impaired heart function, and for the first time, they added arrhythmogenic right ventricular cardiomyopathy to the already established three major groups. Unclassified cardiomyopathies and specific cardiomyopathies (previously called particular heart muscle diseases) were also included in this classification. The unclassified included conditions that did not fit into the major groups, such as noncompacted myocardium, mitochondrial fibroelastosis, and systolic dysfunction with minimal dilation. While specific cardiomyopathies included ischemic, valvular, and hypertensive cardiomyopathies, it confuses the true meaning of myocardial diseases. They linked dilated and arrhythmogenic cardiomyopathies to cytoskeletal mutations, while hypertrophic and restrictive forms were associated with sarcomeric mutations. Although rapid progress in technological and genetic advances has rendered some aspects of the 1995/1996 schema obsolete, its core morphological categories remain a foundational clinical conceptual model. The International Society and Federation of Cardiology was reorganized as the World Heart Federation (WHF) in 1998.

In 2006, the American Heart Association (AHA) published a scientific statement with a new cardiomyopathy classification based on the evolution of genetic testing and diagnostic imaging methods in cardiology, designed to facilitate communication between clinicians and researchers. It was the first classification to include channelopathies and conduction system disorders (channelopathies, such as long or short QT and Brugada syndrome). The AHA classification defined cardiomyopathies as a heterogeneous group of myocardial diseases associated with mechanical and/or electrical dysfunction, often associated with a genetic cause, and may be systemic or limited to the heart. Hence, cardiomyopathies were subdivided into primary and secondary. The primary cardiomyopathies are confined to the heart and are divided into genetic, mixed (genetic and nongenetic), and acquired, while the secondary cardiomyopathies were recognized as part of systemic diseases and were previously referred to as specific cardiomyopathies. However, some limitations were observed in this classification, which included a lack of recommendations for exercise or pregnancy, weak sudden cardiac death risk assessment, and inclusion of other traits and syndromes as cardiomyopathies, which to date are not considered cardiomyopathies by other scientific associations, for example, myocarditis, LVNC, and takotsubo syndrome.

In contrast, the European Society of Cardiology (ESC) 2008 adopted a different approach and classified cardiomyopathies based on clinically oriented phenotypes into six: dilated, hypertrophic, restrictive, arrhythmogenic right ventricular cardiomyopathy, and unclassified. These were further subdivided into familial and nonfamilial types, with familial disease defined by recurrence in more than one family member or a phenotype that could be caused by the same genetic mutation, while the nonfamilial disease is defined by the absence of relevant family history and classified as idiopathic or acquired. This historical moment surprisingly abandoned the difference between cardiomyopathies and specific heart muscle diseases. ESC defined cardiomyopathies as “heart muscle disorders in which the heart muscle is structurally and functionally abnormal and not explained by coronary artery disease, hypertension, valvular, or congenital heart disease.” The European classification excludes ischemia or infarction as an underlying cause of DCM. They argued that their inclusion of ischemia and infarction would blur the distinction between cardiomyopathy and heart failure, although mild coronary artery disease may coexist with dilated cardiomyopathy without accounting for left ventricular dysfunction. The ESC also went further to point out some weaknesses in the AHA classification, including the difficulty of distinguishing primary from secondary cardiomyopathies as scientific knowledge evolved, the overlap between cardiac and systemic manifestations, and the inclusion of channelopathies, which often lack structural or functional myocardial abnormalities.

In 2013, Arbustini et al. proposed a new classification, similar to the TNM (tumor, node, metastasis) staging system for cancer, known as MOGE(S), where M refers to morpho-functional phenotype, O refers to organ/system involvement, G refers to genetic or familial inheritance pattern, and E refers to etiology and functional status (S) using the American College of Cardiology (ACC)/AHA (A to D) and the New York Heart Association functional classes (I to IV). The MOGE(S) classification defined cardiomyopathy as morphological and functional abnormalities of the heart muscles in the absence of other diseases that may cause this phenotype. The main advantage of this classification is the global evaluation to improve diagnosis, treatment, and outcomes of cardiomyopathy patients and their families; additionally, it facilitates research through a multicenter classification. However, MOGE(S) had some limitations that are believed to have contributed to it not widely used in routine clinical practice and research. It does not include several clinically relevant conditions, such as tachycardia-induced cardiomyopathy, endocrine-related cardiomyopathies, and peripartum cardiomyopathy in the etiological classification. It also does not adequately capture early or evolving disease stages, the severity of ventricular dysfunction, acute heart failure, or sudden cardiac death risk, which may affect a patient’s treatment and prognosis.

The ESC developed a new cardiomyopathies guideline in 2023, reflecting the emerging scientific evidence and new concepts. They introduced the nondilated left ventricular cardiomyopathy classification and excluded left ventricular noncompacted cardiomyopathy from the main classification, proposing that it should be referred to as left ventricular hypertrabeculation because the current emerging evidence considered it a phenotype rather than a cardiomyopathy. This new guideline also recommends abolishing the use of the term “stress cardiomyopathy (Takotsubo syndrome)” as a cardiomyopathy.

The integration of genetic testing with hybrid cardiac imaging in the near future will enhance patient management in clinical practice. Before now, clinical genetic testing in cardiomyopathy was primarily used to screen families and identify rare disease phenocopies. Currently, several clinical trials assessing gene therapy for cardiomyopathies are ongoing and include those secondary to X-linked (Danon disease, Fabry disease, and Duchenne muscular dystrophy disease), autosomal recessive (Pompe and Friedreich ataxia diseases), and autosomal dominant transthyretin (TTR) amyloidosis, etc. It is believed that with the advent of gene replacement, RNA therapeutics, and novel small-molecule therapies, determining the genetic cause will be of vital significance in managing cardiomyopathies. Furthermore, multimodality imaging plays a crucial role in the initial assessment, diagnosis, and treatment of patients with cardiomyopathy. Finally, with the advent of these new etiology-driven genetic therapies and imaging approaches, new emerging concepts are likely to arise, which could enable researchers to propose new classification approaches for cardiomyopathies in a few years.

Classification of cardiomyopathies

WHO/ISFC Task Force Classification of Cardiomyopathies (1995)

1. Dilated cardiomyopathy (DCM)
2. Hypertrophic cardiomyopathy (HCM)
3. Restrictive cardiomyopathy
4. Arrhythmogenic right ventricular cardiomyopathy (right ventricular dysplasia)
5. Unclassified cardiomyopathies, e.g., Mitochondrial fibroelastosis, Noncompacted myocardium, and Systolic dysfunction with minimal dilation
6. Specific heart muscle diseases of known cause or associated with systemic diseases, e.g., valvular CMP, ischemic CMP, hypertensive CMP, metabolic CMP, and inflammatory CMP.

AHA Classification (2006)

Primary Cardiomyopathies: are confined predominantly to the heart muscles and are further divided into genetic, mixed (genetic and nongenetic), and acquired. Unlike the earlier systems that focused on morphology (dilated, hypertrophic, restrictive), the AHA classification is etiology-based, emphasizing genetic and acquired forms.

• Genetic – caused by mutations in genes encoding cardiac proteins

1. Hypertrophic cardiomyopathy (HCM): Autosomal dominant mutations in sarcomeric proteins (e.g., β-myosin heavy chain, myosin-binding protein C). Characterized by asymmetric septal hypertrophy.
2. Arrhythmogenic right ventricular cardiomyopathy (ARVC/ARVD): Mutations in desmosomal proteins (e.g., plakoglobin, desmoplakin). Leads to fibrofatty replacement of the right ventricular myocardium.
3. Left ventricular noncompaction (LVNC): Arrested myocardial development; characterized by prominent trabeculations and deep recesses.
4. Ion channelopathies: Electrical disorders due to ion channel mutations (e.g., long QT, short QT, Brugada, catecholaminergic polymorphic ventricular tachycardia). These may occur with or without structural abnormalities.
5. Conduction system diseases: Genetic abnormalities in ion channel or cytoskeletal genes affecting conduction (e.g., progressive cardiac conduction disease).
6. Mitochondrial myopathies: affect oxidative phosphorylation and may cause cardiomyopathy and skeletal muscle disease.
7. Glycogen storage: PRKAGE2 danon

• Mixed (genetic and non-genetic) – These have both familial and nonfamilial forms.

1. Dilated cardiomyopathy (DCM): Characterized by ventricular dilation and systolic dysfunction. It may result from genetic mutations, toxins (alcohol), infections, or autoimmune causes.
2. Restrictive cardiomyopathy (RCM): Impaired ventricular filling with preserved systolic function. May be familial (e.g., troponin mutations) or acquired (e.g., amyloidosis, sarcoidosis).

           (a) Non-dilated

           (b) Non-hypertrophied

Acquired – Result from external factors or systemic diseases that primarily affect the myocardium (heart-specific problems caused by external factors).

1. Inflammatory (myocarditis): Viral (e.g., coxsackievirus), bacterial, or autoimmune inflammation of the myocardium.
2. Stress-induced (Takotsubo): Transient LV dysfunction due to catecholamine surge, often triggered by emotional or physical stress.
3. Peripartum cardiomyopathy: Heart failure developing in the last month of pregnancy or within 5 months postpartum.
4. Tachycardia-induced: Persistent rapid arrhythmias leading to myocardial dysfunction.
5. Infiltrative / Toxic: Due to agents like alcohol, chemotherapy (doxorubicin), or metabolic abnormalities.
6. Infants of insulin-dependent diabetic mothers.

Secondary Cardiomyopathies: These occur as part of a systemic disorder that secondarily involves the heart. The cardiac abnormality is a manifestation of another disease. 

• Infiltrative: Amyloidosis, sarcoidosis, hemochromatosis
• Storage diseases: Fabry disease, glycogen storage disorders
• Endocrine / Metabolic: Diabetes, thyroid disease, acromegaly
• Nutritional deficiencies: Thiamine (beriberi), selenium deficiency
• Autoimmune / Collagen vascular diseases: Systemic lupus erythematosus, scleroderma 
• Neuromuscular disorders: Duchenne muscular dystrophy, Friedreich’s ataxia
• Toxic: Alcohol, cocaine, chemotherapeutic agents

ESC Classification (2008)

The European Society of Cardiology (ESC) Working Group on Myocardial and Pericardial Diseases proposed a comprehensive classification of cardiomyopathies in 2008, refined in 2016, to unify terminology and facilitate both clinical and genetic understanding. Unlike the American Heart Association (AHA) system, which is primarily etiology-based, the ESC classification adopts a morpho-functional approach, and further subcategorizes each by genetic and familial background as either:

• Familial/Genetic: Caused by mutations inherited in an autosomal dominant, recessive, or mitochondrial pattern.
• Non-familial/Nongenetic: idiopathic or acquired forms due to environmental, infectious, toxic, or metabolic causes.

The ESC classifies cardiomyopathies into five principal types of cardiomyopathies according to ventricular structure and function:

Hypertrophic Cardiomyopathy (HCM): Unexplained increase in myocardial wall thickness not due to abnormal loading conditions. It is characterized by asymmetric septal hypertrophy, preserved or hyperdynamic systolic function, and diastolic dysfunction.

  (a). Familial/Genetic:

• Sarcomeric protein mutations e.g., ß myosin heavy chain (MYH7), myosin-binding protein (MYBPC3), troponin T/I/C, cardiac actin
• Glycogen storage disease (e.g., Pompe; PRKAG2, Forbes’, Danon)
• Lysosomal storage diseases (e.g., Anderson–Fabry, Hurler’s)
• Disorders of fatty acid metabolism, e.g., Carnitine deficiency
• Phosphorylase B kinase deficiency
•  Mitochondrial cytopathies
• Syndromic HCM, e.g., Noonan’s syndrome, LEOPARD syndrome, Friedreich’s ataxia, Beckwith–Wiedemann syndrome, and Swyer’s syndrome.

  (b). Non-familial/Nongenetic:

• Obesity
• Infants of diabetic mothers
• Athletic training
• Amyloid (AL/prealbumin)

Dilated Cardiomyopathy (DCM): Dilatation and impaired contraction of the left ventricle or both ventricles, unrelated to abnormal loading or coronary disease. It is mainly characterized by ventricular enlargement, systolic dysfunction, mural thrombus formation, and conduction abnormalities.

  (a). Familial/Genetic:

• Sarcomeric protein mutations, e.g., TTN (titin)
• Z-band Muscle, e.g., LIM protein, TCAP 
• Cytoskeletal genes, e.g., Dystrophin, Desmin, Metavinculin, Sarcoglycan complex, CRYAB, Epicardin
• Nuclear membrane, e.g., Lamin A/C, Emerin 
• Mildly dilated CM 
• Intercalated disc protein mutations 
• Mitochondrial cytopathy

  (b).Non-familial/Nongenetic:

• Myocarditis (infective/toxic/ immune)
• Kawasaki disease 
• Eosinophilic (Churg Strauss syndrome) 
• Viral persistence 
• Drugs 
• Pregnancy 
• Endocrine — diabetes, thyroid
• Nutritional — thiamine, carnitine, selenium, hypophosphataemia, hypocalcaemia 
• Alcohol 
• Tachycardiomyopathy

Restrictive Cardiomyopathy (RCM): Non-dilated ventricles with impaired ventricular filling and preserved systolic function. Its main features include biatrial enlargement, restrictive filling pattern, and elevated filling pressures.

  (a). Familial/Genetic:

• Sarcomeric protein mutations, e.g., Troponin I (RCM þ/2 HCM), Essential light chain of myosin 
• Familial amyloidosis, e.g., Transthyretin (RCMþ neuropathy), Apolipoprotein (RCMþ nephropathy) 
• Desminopathy 
• Pseuxanthoma elasticum 
• Haemochromatosis 
• Anderson–Fabry disease 
• Glycogen storage disease

  (b). Non-familial/Nongenetic:

• Amyloid (AL/prealbumin) 
• Scleroderma 
• Endomyocardial fibrosis, e.g., Hypereosinophilic syndrome, Idiopathic, Chromosomal cause, Drugs (serotonin, methysergide, ergotamine, mercurial agents, busulfan)
• Carcinoid heart disease 
• Metastatic cancers 
• Radiation Drugs (anthracyclines)

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): Fibrofatty replacement of right ventricular myocardium leading to arrhythmias and structural abnormalities. It is characterized by RV dilation, regional wall motion abnormalities, and ventricular arrhythmias of RV origin.

  (a). Familial/Genetic:

• Desmosomal gene mutations (Intercalated disc protein mutations) — Plakoglobin, Desmoplakin, Plakophilin 2, Desmoglein 2, Desmocollin 2, 
• Cardiac ryanodine receptor (RyR2) 
• Transforming growth factor-b3 (TGFb3)
• Non-familial/Nongenetic: post-inflammatory myocardial damage, cardiac sarcoidosis, chronic myocarditis.

Unclassified Cardiomyopathies: Disorders not fitting into the above categories. Examples include left ventricular noncompaction and Takotsubo cardiomyopathy.

  (a) Familial/Genetic: 

• Left ventricular non-compaction
• Barth syndrome 
• Lamin A/C 
• ZASP a-dystrobre

  (b) Non-familial/Nongenetic: Tako Tsubo cardiomyopathy

ESC Classification (2023)

• Hypertrophic Cardiomyopathy (HCM)
• Dilated Cardiomyopathy (DCM)
• Restrictive Cardiomyopathy (RCM) 
• Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)
• Nondilated left ventricular cardiomyopathy (NDLVC)

The MOGE(S) Classification

Each letter in MOGE(S) represents a specific dimension of disease characterization as described below.

M: Morpho-functional phenotype: The “M” notation provides the clinical diagnosis, which corresponds to the description of the phenotype, such as MD (DCM), MH (HCM), MA (ARVC), MR (RCM), and MNC (LVNC). This notation is similar to the current clinical classification of cardiomyopathies. The first clinically used diagnosis is labeled as a subscript to the “M.” If HCM evolves into a dilated congestive phenotype or presents with a significant restrictive pattern, it can be described as MH+D or MH+R. Multiple other combinations may be possible, such as MD+NC or MA+NC, or MH+NC. The “M” notation also allows the description of early phenotypes. For instance, conditions where diagnostic criteria for the suspected clinical phenotype (such as DCM or HCM) are not fulfilled, but the imaging data indicate an increased LV diameter and a borderline LV function (ME[D]), or a possible LV hypertrophy (ME[H]) in carriers of the mutation that has caused the disease in the family. Clinically unaffected mutation carriers are described as M0. In situations where information about the phenotype can not be obtained from the deceased relatives, the description is MNA. Subscripts can be used to further specify which ventricle is involved, as shown: L (left ventricle), R (right ventricle), and B (biventricular).

O: The Involved Organs: The organs involved can either be the heart only (OH) or in combination with other organ systems, such as skeletal muscle (OH+M), the auditory system (OH+A), kidney (OH+K), the nervous system (OH+N), liver (OH+Li), the gastrointestinal system (OH+G), cutaneous (OH+C), ocular or eyes (OH+E), respiratory or lung (OH+Lu), or mental retardation (OH+MR). Healthy mutation carriers are described as O0, because the heart is still clinically unaffected; it complements the M0 notation. Other organ/system involvement makes it easy to identify syndromes. The simple combination of data on cardiac phenotype and involvement of the kidney, liver, lung, or gastrointestinal system can usefully restrict the field of diagnostic hypotheses and can address focused genetic testing.

G: Genetic or familial inheritance pattern: The inheritance pattern derived clinically by family pedigree or screening includes the following and their notations: autosomal dominant (GAD), autosomal recessive (GAR), X-linked (GXL), X-linked recessive (GXLR), X-linked dominant (GXLD), and matrilineal (GM) transmission. Uniquely affected family members with a documented disease mutation are described as de novo (GDN) or as having phenotypically sporadic (GS) cardiomyopathy. Patients with negative or unknown family history (GN or GU) and family history not investigated so far (G0) can also be specified as shown.

E: Etiology: The notation “E” includes a description in 2 steps. The first step describes the underlying cause of the cardiomyopathy, which may be of genetic (EG) or nongenetic cause. The latter needs to be addressed individually, as in the following paragraph; the nonidentifiable cause is also noted (EN). The second notation defines precise etiology. For example, the gene mutation needs to be specified next to the EG, and similarly, the cause of the underlying disease in nongenetic cardiomyopathies also needs to be explained. In genetic cardiomyopathies, the disease gene and mutation(s) can be added, such as in the case of HCM (EG-MYH7 [p. Arg403Glu]) or familial amyloidosis (EG-ATTR [p. Val122Ile]). The “E” specification also allows the identification of family members who are noncarriers of the mutation that causes the disease in the family (EG-Neg), the obligate carrier (EG-OC), or the obligate noncarrier (EG-ONC). For the unavailability of a genetic test, the notation EG-NA. Genetically orphan patients are labeled as negative: EG-N (genetic defect not identified) after a complete screening of all known disease genes in familial disease. EG-0 indicates that genetic testing was not done or was not feasible for any reason. The MOGE(S) system points out mutations that do not fully segregate with the phenotype or are part of incomplete genotyping.

The causes of nongenetic cardiomyopathies can be described as viral (V) (the first notation), adding the virus (e.g., Coxsackie B3 virus [CB3], human cytomegalovirus [HCMV], or Epstein-Barr virus [EBV] presented as EV-HCMV, EV-CB3, or EV-EBV) for the second notation; the infectious, nonviral diseases (EI) may be presented with further specification of the infectious agent whenever possible. When the myocarditis is the proven cause of the myocardial disease (EM), the second notation could specify the origin of the myocarditis, such as sarcoidosis (EM-Sarcoid) or noninfectious giant cell myocarditis. An autoimmune etiology, either suspected or proven (EAI-S or EA-P), may populate the first notation, followed by the specific etiology, such as rheumatoid arthritis or systemic lupus erythematosus. The MOGE(S) app allows the description of each proven diagnosis (e.g., MD OH+C+S G0 EAI-P-Rheumatoid Arthritis SC-II or MD OH+C G0 EAI-P-Rheumatoid Arthritis SB-II). Nonheritable amyloidosis (EA-K, EA-L, or EA-SAA) represents kappa, lambda, or serum amyloid A protein characterization, respectively. Toxic cardiomyopathies, either endogenous, such as pheochromocytoma-related cardiomyopathy, or drug-induced cardiomyopathy, are described (ET-Pheo or ET-Chloroquine). When the former is described in the context of a syndrome (such as VHL, MEN2A/2B, or NF1), the description can be implemented by adding the name of the syndrome (i.e., ET-Pheo-VHL). Loeffler’s eosinophilic endomyocarditis can be described according to the cause as either being idiopathic or a part of a myeloproliferative disorder associated with the somatic chromosomal rearrangement of PDGFRα or PDGFRβ genes that generate a fusion gene encoding for constitutively active PDGFR tyrosine kinases.

S: Stage/Functional status: “S,” in 2 notations, describes the heart failure ACC/AHA stage (A to D) coupled with NYHA functional class (I to IV), presented as SA-I or SC-II, and so on. The notation “S” is optional but may be useful for the description of early cardiomyopathy. The ACC/AHA guidelines include patients with a family history of cardiomyopathy in stage A. In families with known mutations, the diagnosis of early cardiomyopathies can be further supported by the presence of the mutation(s), whereas in genetically orphan familial cardiomyopathy, only the early imaging markers of the disease can be highlighted. This description is useful particularly for individuals seeking a definitive recommendation from the physician about their sport worthiness. Although criteria for early diagnosis of cardiomyopathy are not systematically described, increasingly, family screening and monitoring have revealed that the cardiomyopathies likely serve a long preclinical or subclinical course before the manifestation of symptoms.

Treatment Guidelines of Cardiomyopathy

The European Society of Cardiology (ESC) released new guidelines for managing cardiomyopathies (excluding hypertrophic cardiomyopathy) in August 2023. The goal of these guidelines was to improve diagnosis and patient care and also support families affected by inherited heart muscle disease. The new guidelines emphasize coordinated and lifelong care with the following core recommendations:

• All cardiomyopathy patients and their relatives should have access to multidisciplinary teams with experience in diagnosing and managing cardiomyopathy.
• All adolescents with cardiomyopathy should have timely and adequate preparation for transitioning their care from pediatric to adult services, ensuring continuous and informed care.

Diagnosis 

• Every patient with suspected or confirmed cardiomyopathy should undergo: 

1. Clinical assessment
2. Electrocardiography and Holter monitoring.
3. Laboratory tests to assess the cause and disease severity, identify extracardiac manifestations, and gauge secondary organ dysfunction.
4. Echocardiography and multimodality imaging.
5. A 3–4 generation family tree to identify inheritance patterns and relatives who are at-risk.

• Cardiac MRI, including contrast imaging, during initial assessment to better characterize the heart muscle, evaluate LV and RV systolic (global and regional) function, and LV diastolic function for monitoring the course of disease, risk stratification, and management.
• Nuclear scintigraphy DPD/PYP/HMDP (3,3-diphosphono-1,2 propanodicarboxylic acid/pyrophosphate/hydroxymethylene diphosphonate) should be done when cardiac amyloidosis is suspected.
• Genetic counseling, education, and psychosocial support for families with or suspected of inherited cardiomyopathy, whether or not genetic testing is planned.
• Genetic testing when results influence diagnosis, treatment plans, family screening, and reproductive decisions, or when it allows cascade genetic evaluation of their relatives who would otherwise be enrolled into long-term surveillance. Postmortem genetic testing is also recommended for deceased patients if a genetic diagnosis would aid in the management of surviving family members.
• Those with a family history of premature sudden cardiac death or an inherited cardiomyopathy or who receive an ICD, and all those who undergo genetic testing for cardiomyopathy, should receive pre- and post-test genetic counseling. Prenatal diagnostic testing should be done in early pregnancy to allow decision-making about pregnancy continuation or coordination.

Management

• For patients with advanced heart failure (NYHA class III-IV) or intractable ventricular arrhythmia that fails to respond to medical/invasive/device therapy, the ESC recommends heart transplantation for eligible cardiomyopathy candidates, in the absence of absolute contraindications.
• Oral anticoagulants are recommended to reduce the risk of stroke and thromboembolic events and should be given to:

1. All patients with hypertrophic cardiomyopathy, cardiac amyloidosis, atrial fibrillation (AF), or atrial flutter, in the absence of contraindications.
2. Patients with dilated cardiomyopathy, nondilated LV cardiomyopathy, or arrhythmogenic RV cardiomyopathy (ARVC), and AF or atrial flutter with a CHA2DS2-VASc score (congestive heart failure or LV dysfunction, hypertension, age ≥ 75 years [doubled], diabetes, stroke [doubled], vascular disease, age 65-74 years, female sex) of at least 2 in men or at least 3 in women.

• Atrial fibrillation catheter ablation is recommended for:

1. Rhythm control after failure or intolerance of one class I or III antiarrhythmic agent in patients with paroxysmal or persistent AF and cardiomyopathy.
2. Improvement of LV dysfunction in patients with AF and cardiomyopathy when tachycardia is the most likely cause, independent of their symptom status.

• Patients with cardiomyopathy should undergo lifestyle modification and targeted therapy of intercurrent conditions to reduce the AF burden and symptom severity.
• Patients who are likely to have a good quality of survival longer than 1 year may require an implantable cardioverter-defibrillator (ICD), especially survivors of cardiac arrest or those with unstable ventricular rhythms in DCM.
• For patients with irreversible causes, the ESC recommends ICD implantation in HCM, DCM, and ARVC survivors of cardiac arrest due to ventricular tachycardia (VT) or ventricular fibrillation (VF), or who have sustained ventricular arrhythmia that results in syncope or hemodynamic instability.
• All patients with cardiomyopathy who have not experienced a previous cardiac arrest or sustained ventricular arrhythmia should undergo thorough risk stratification for sudden cardiac death at their first evaluation and every one to two years, or when symptoms change, to help determine who needs preventive therapies.
• When an ICD is required, physicians also evaluate whether cardiac resynchronization therapy (CRT) could further boost heart efficiency and outcomes.
• All stable patients with cardiomyopathy should have routine check-ups with a yearly or two-year multiparametric approach that includes an ECG and an echocardiogram to monitor heart structure and function. If symptoms suddenly worsen, clinicians reassess using ECG and multimodality imaging to detect any new changes early.
• After genetic testing and family screening:

1. If relatives carry the same disease-causing gene, they should undergo heart evaluations with a multiparametric approach, including ECGs, imaging, and long-term monitoring.
2. Relatives without the mutation and no symptoms can be discharged from follow-up, but should return if symptoms arise or new family information emerges.
3. If no genetic mutation is found or genetic testing is not done, first-degree relatives still need an initial heart evaluation with a multiparametric approach.

• All individuals with cardiomyopathy should be encouraged to participate in regular low- to moderate-intensity exercise if they are able. Individualized risk assessment should be done for all patients with cardiomyopathy so that exercise plans are safe and tailored.
• All women should have access to pre-pregnancy risk assessment, using the WHO maternal risk guidelines. Men and women should receive counseling on safe contraception and the potential hereditary risks of passing on the condition to offspring. Most women can undergo vaginal delivery, except in severe heart failure, major obstruction, or other contraindications.
• Review and adjust medications during pregnancy, and those with AF may need anticoagulation with low molecular weight heparin or vitamin K antagonists based on gestational stage.
• All patients with cardiomyopathy who undergo surgery should have access to peri-op ECG monitoring, and those with suspected/confirmed heart failure may need updated echocardiography and BNP/NT-proBNP testing to help guide safety planning before higher-risk procedures.

Conclusion

Cardiomyopathy isn’t what it used to be. What started as a vague label for heart muscle problems has turned into a whole collection of heart conditions, each with its own structure, function, and genetic quirks. Over time, the ways we classify these diseases, starting with the old WHO system and moving through the AHA, ESC, and MOGE(S) frameworks, have made it a lot easier for doctors to figure out what’s going on and make better decisions for their patients.

The latest ESC guidelines from 2023 really bring things up to date. They focus on the patient, not just the disease, and pull in genetics, advanced imaging, and a team approach to care. These guidelines clear up a lot of the confusion around definitions and push for a lifetime management plan. They also highlight the importance of screening family members, evaluating risk for sudden cardiac death, and offering tailored advice about things like exercise, pregnancy, and advanced treatments.

With genetic testing, new imaging techniques, and targeted treatments getting better all the time, the way we manage cardiomyopathies keeps moving toward precision medicine.