In myocarditis (synonyms: Old myocarditis; concomitant myocarditis; chronic myocarditis; chronic interstitial myocarditis; fibroid heart disease; fibrous myocarditis; cardiac fibroid; cardiac fibrosis; interstitial myocarditis; cardiac fibrosis; myofibrosis cordis; myocarditis; myocardial fibrosis; myocarditis; myocarditis with arteriosclerosis; panmyocarditis; progressive myocarditis; senile heart disease; senile myocarditis; ICD-10-GM I51. 4: Myocarditis, unspecified) is the inflammation of the heart muscle (myocardium). The inflammation can also spread to the pericardium (heart sac). This is then referred to as perimyocarditis.
In myocarditis, the myocardium‘s ability to contract is impaired or weakened.
Myocarditis can be differentiated as follows:
- According to the course in:
- Acute form
- Chronic form – This may develop into dilated cardiomyopathy (DCM, enlargement of the myocardium with concomitant loss of contractile force). Heart failure (cardiac insufficiency) is the result.
- According to histology (microscopic examination of tissue) in:
- Parenchymatous myocarditis – the myocardium is directly affected; necrosis (cell death) of individual fibers or groups of muscle fibers is seen
- Interstitial myocarditis – in this case there is interstitial mononuclear inflammation (the tissue affected is that which lies between the actual function-bearing tissues, the parenchyma, i.e. the myocardium) accompanied by myocyte necrosis (cell death of muscle cells). Myocardial necrosis often leads to dilated cardiomyopathy as a consequence.
- By etiology (cause) in:
- infectious myocarditis
- 50% of cases are viruses
- Bacteria
- Mycoses (fungi), protozoa and parasites.
- Toxic myocarditis (due to toxicity).
- Idiopathic (without apparent cause) myocarditis.
- Autoimmune myocarditis – due to a reaction against endogenous cardiac myosin, myocarditis occurs.
- infectious myocarditis
Myocardial involvement is thought to occur in approximately 1-5% of patients who have a viral infection.
Sex ratio: more common in young men than in women.
Exact prevalence (disease incidence) data are not possible, because myocarditis in the majority of cases without symptoms. In autopsies, the prevalence is 2-5%.
Course and prognosis: In the majority of cases, myocarditis is asymptomatic and heals spontaneously. However, it can also cause cardiac arrhythmias (usually harmless).Possible complications include heart failure and stressful cardiac arrhythmias, which can even lead to sudden cardiac death. In about 50% of patients, myocarditis heals in the first 2 to 4 weeks. Approximately 25% of patients have permanent cardiac dysfunction (“heart-related dysfunction”).Approximately 12.5-25% die or develop terminal heart failure (stage of heart failure in which pump function is just sufficient to keep the body alive → heart transplantation required).
As the disease progresses, patients with myocarditis require cardiologic follow-up or care.
