Cardiomyopathies (synonyms: Myocardiopathy; Cardiomyopathies; CM; ICD-10-GM I42.-: Cardiomyopathy) are diseases of the myocardium (heart muscle). They are associated with mechanical and/or electrical dysfunction of the heart. In addition, there is usually thickening of the myocardium, enlargement of the heart, or dilatation (widening) of one or both ventricles (heart chambers). The forms of cardiomyopathy are differentiated according to morphological (shape-related) and clinical characteristics (see below “Symptoms – complaints”). In addition to mixed and transitional forms, five main forms of cardiomyopathy are distinguished – classification according to WHO (World Health Organization):
- Dilated (dilated) cardiomyopathy (DCM; ICD-10-GM I42.0: Dilated cardiomyopathy) – Systolic pump dysfunction with cardiomegaly (enlargement of the myocardium (heart muscle)) and impaired ejection fraction (EF; ejection fraction).
- Hypertrophic (enlarged) cardiomyopathy (HCM; ICD-10-GM I42.2: Other hypertrophic cardiomyopathy) – The thickness of the heart muscle, especially the left ventricular wall, increases.
- With and without obstruction (narrowing) of the left ventricular outflow tract:
- Hypertrophic nonobstructive cardiomyopathy (HNCM; ICD-10-GM I42.2: Other hypertrophic cardiomyopathy) – approximately one-third of cases.
- Hypertrophic obstructive cardiomyopathy (HOCM; synonym: Idiopathic hypertrophic subaortic stenosis (IHSS); ICD-10-GM I42.1: Hypertrophic obstructive cardiomyopathy) – approximately two-thirds of cases; the muscles of the left ventricle, particularly the ventricular septum (ventricular partition), thicken.
- Note: Since approximately 30-40% of patients without obstruction at rest develop obstruction under stress, provocation tests are required to distinguish the two subtypes HNCM and HOCM!
- With and without obstruction (narrowing) of the left ventricular outflow tract:
- Restrictive (restricted) cardiomyopathy (RCM; ICD-10-GM I42.5: Other restrictive cardiomyopathy) – stiffening of the ventricular walls due to scarring of muscle tissue or deposition of amyloids (proteins/proteins).
- Arrhythmogenic right ventricular cardiomyopathy (ARVC; ARVCM; synonyms: Arrhythmogenic right ventricular dysplasia cardiomyopathy; ARVD; ARVC; ICD-10-GM I42.80: Arrhythmogenic right ventricular cardiomyopathy [ARVCM]) – deposition of connective and adipose tissue in the muscle tissue of the right ventricle (heart chamber).
- Nonclassifiable cardiomyopathy (NKCM).
- Collection of various disorders, e.g.:
- Isolated (ventricular) noncompaction cardiomyopathy (NCCM).
- Collection of various disorders, e.g.:
For more information, see “Classification”. Sex ratio Dilated cardiomyopathy (DCM): males to females is 2: 1. Hypertrophic cardiomyopathy (HCM): males are slightly more commonly affected than females. Arrhythmogenic right ventricular cardiomyopathy (ARVC): males to females is 2: 1. Frequency peaks Cardiomyopathies can occur at any age, but predominantly between the ages of 20 and 50. Arrhythmogenic right ventricular cardiomyopathy (ARVC) occurs predominantly around age 30. The prevalence of dilated cardiomyopathy (DCM) is 40 cases per 100,000 inhabitants (in Germany). It is the most common idiopathic (without an identifiable cause) cardiomyopathy. The prevalence of hypertrophic cardiomyopathy (HCM) is 200 diseases per 100,000 inhabitants (in Germany). HCM is the most common hereditary (inherited) heart disease. The prevalence of arrhythmogenic right ventricular cardiomyopathy (ARVC) is 1 disease per 1,000 to 2,000 inhabitants (in Germany). Isolated (ventricular) noncompaction cardiomyopathy (NCCM; nonclassifiable cardiomyopathy) accounts for approximately 9% of primary cardiomyopathies in children. The incidence (frequency of new cases) of dilated cardiomyopathy (DCM) is approximately 6 cases per 100,000 population per year (in Germany). The incidence of hypertrophic cardiomyopathy (HCM) is approximately 19 diseases per 100,000 population per year (in Germany).The incidence of primary cardiomyopathies in children is 1.13 diseases per 100,000 children and adolescents (< 19 years) (in North America). In children, dilated cardiomyopathy (51%) and hypertrophic cardiomyopathy (42%) are the most common.Course and prognosis When the heart enlarges, it can no longer contract sufficiently and the ejection fraction (EF; Auswurffraktion) decreases. If the myocardium (heart muscle) thickens, not enough blood flows into the ventricles (heart chambers). Over time, both of these processes can lead to heart failure (cardiac insufficiency) or sudden cardiac death. The prognosis of dilated cardiomyopathy (DCM) depends on the degree of heart failure (cardiac insufficiency; NYHA class: ≥ III = poor), ejection fraction (ejection rate < 20% = poor), diastolic filling characteristics of the left ventricle (left heart chamber; restrictive = poor), and evidence of myocardial fibrosis (MRI). Mortality (number of deaths in a given period, based on the number of the population in question) is up to 10% per year. The 10-year survival rate for dilated cardiomyopathy is approximately 10-20%. Hypertrophic cardiomyopathy (HCM) is asymptomatic for a long time. Especially in the non-obstructive form, it is usually an incidental finding. Women with hypertrophic cardiomyopathy have a worse prognosis than men with this heart disease. Mortality is approximately 1-5% per year in adults and up to 6% per year in children and adolescents. In most cases, ventricular arrhythmias (arrhythmias originating in the heart chambers) are the cause of death. In this context, sudden cardiac death often strikes young, male patients. As restrictive cardiomyopathy (RCM) progresses, diastolic ventricular dysfunction increases. Therapy-resistant right heart failure (restriction of pumping function of the right heart) develops with inflow congestion in front of the right heart. Without heart transplantation, the prognosis is poor. In the setting of arrhythmogenic right ventricular cardiomyopathy (ARVC), affected individuals can lead relatively normal lives. They occasionally suffer from arrhythmias (heart rhythm disturbances). Implantation of an ICD (implantable cardioverter/defibrillator) can reduce the rate of fatal arrhythmias. Arrhythmogenic right ventricular cardiomyopathy, along with hypertrophic cardiomyopathy, is a common cause of sudden cardiac death in athletes. Without therapy, the 10-year lethality (mortality relative to the total number of people with the disease) is approximately 30%. Note: The proportion of patients with other family members suffering from cardiomyopathy is very high. The proportion was 48.5% in HCM, 25.2% in DCM, 40.6% in ARVC, and 30% in RCM.
