Diagnosis
Diagnosis of myocarditis belongs to one of the most challenging in cardiology because of many reasons. One of them is, for example, an enormous variability of symptoms and manifestations of the disease including asymptomatic individuals, heart failure, cardiogenic shock, sudden death and patients with myocarditis mimicking ischemic heart disease. There is no single examination which could confirm the diagnosis with 100% certainty. Diagnosis is thus very frequently based on a process of elimination. There are all kinds of examinations used for the diagnosis of myocarditis and ICMP – ECG, ECHO, laboratory examination of the myocardial damage, CMRI and EMB.
Prognosis
It is difficult to determine the prognosis of myocarditis and ICMP because it depends on a number of different factors including age and disease type. The highest mortality and heart transplant necessity are in GCM with 48 to 89 %. In HIV/AIDS patients with myocarditis, it is 15 to 55 % and it is similar in cardiac sarcoidosis with 17 to 48 % 10-year survival rate. In cardiac sarcoidosis and GCM, the prognosis is influenced even by early initiation of immunosuppressive therapy.
The prognosis of patients depends of course on clinical presentation, NYHA class, the severity of systolic dysfunction of left or right ventricle, ECG finding in which prolongation of QRS complex was put in association with higher risk of mortality or heart transplant, and it depends also on the levels of laboratory parameters – troponin, BNP etc. Prognosis is usually good in patients with the mild course of the disease and with preserved LV EF. There were described as prognostically significant also cardiac MRI findings (specifically LGE), and EMB results.
More information may be found here.
Retrospective study
This chapter is dedicated to the retrospective statistical evaluation of 30 individuals with the diagnosis of myocarditis and perimyocarditis hospitalized between 1/1/2002 and 31/12/2016 on the Department of Cardiology of Na Homolce Hospital, Prague. The aim of this work was to descriptively evaluate the findings and results of performed examinations with statistical methods, further, to evaluate the heterogeneity of the disease and to demonstrate theoretical knowledge on a specific group of patients and also to evaluate findings and results of performed examinations in patients with initial negative and positive troponin I level with cut-off 0,06 ng/ml. You may find here detailed information about the methods, results and discussion. Author of the study: Jan Habásko. More information may be found here.
References
In this category, you may find list of references which have been used during the workings on chapters in the Version for experts of the web guide www.myokarditida.cz. More information may be found here.
Aetiology
Aetiology of myocarditis is highly varied and includes both infectious and non-infectious agents. The introduction of PCR and electron microscopy for the analysis of bioptically taken samples of the myocardium of patients with myocarditis had a big importance for the discovery of infectious agents causing the disease. he most frequent viral agents of myocarditis and ICMP generally are considered PVB19, human herpes virus 6, cytomegalovirus and Epstein-Barr virus
Nevertheless, enteroviruses (primarily Coxsackie), adenoviruses, hepatitis C virus and influenza virus still remain relatively important viral agents of myocarditis and ICMP. In Japan, even cases of H1N1 virus myocarditis were described. In the Czech Republic, myocarditis caused by Borrelia burgdorferi has relatively often incidence. Nonnegligible parts of aetiology of myocarditis are also different cardiotoxic drugs, ethanol and addictive drugs, hypersensitive allergic reactions and systematic inflammatory disorders. Myocarditis remains a frequent complication in patients with HIV infection. More information may be found here.
Groups of agents
Epidemiology
The determination of the epidemiology of myocarditis and ICMP is complicated as a result of a lot of factors including primarily challenging diagnosis lacking for now in a single test which would provide sufficient specificity and sensitivity for the unequivocal determination of myocarditis, and also because of the varied course and manifestation because of what mild forms of myocarditis do not have to be diagnosed. Based on Global Burden of Disease study, over 2,5 million cases of myocarditis and cardiomyopathies was reported worldwide in 2015 including 156 thousand cases of acute myocarditis. Moreover, both groups reported over 20% increase of cases when comparing with 2005.
Myocarditis is considered as a cause of sudden cardiac death, primarily in young individuals, in 9 to 20 %, based on bioptically taken samples of the myocardium. However, some studies have found signs of myocarditis bioptically in up to 42 % of cases. Myocarditis very significantly contributes to the development of the dilated cardiomyopathy (DCMP). It is stated that its part in the development of the DCMP is around 20 %, however an American study which pursued the identification of causes of the DCMP in children, confirmed the diagnosis of myocarditis in 46 % of cases. The representation of myocarditis in the development of heart failure varies from 0,5 to 4 %. The results of these and other studies thus make myocarditis the most frequent aetiology of the DCMP and so it is ICMP.More information may be found here.