The examined group consisted mostly of young males up to the age of 40. Majority of patients (77 %) had increased troponin I level and generally, the examined group showed a strong heterogeneity in the question of symptoms and examinations´ findings. 70 % of patients complained about chest pain, 37 % about chest pressure, shortness of breath (37 %), and running temperature or fever (30 %). Almost 50 % of patients stated recent or acute infection what corresponds with theoretical facts and other studies. For comparison, primarily larger studies were used. For example, when compared with Banka et al. study [166], the prevalence of the above-mentioned characteristics is almost identical. The chest pain was stated by 74 % of patients and signs or anamnesis of recently suffered viral infection stated 42 % of patients. In McNamara et al. study, the prevalence of recent infection was even higher (62,3 %), [146]. Chest pain is generally the most frequent symptom of myocarditis.
1/3 of the examined group complained about vomiting or diarrhoea what was associated in 2 patients with the diagnosis of ulcerative colitis and in other cases, it could be a symptom of an infectious disease. Pre-syncopal and syncopal state were recorded twice. One case was a patient with decreased LV EF and LV dilatation and troponin elevation what could cause the syncopal state. In the second case, troponin examination was negative, however, ECG recorded tachycardia and selective coronarography showed hyperplasia of the right coronary artery.
Heart failure was documented in 4 patients (13 %) with the same representation in patients with negative and positive initial troponin including 3 patients with increased or borderline jugular venous volume and 1 with hepatomegaly. In most of the cases (57 %), the physical examination was normal. Totally, there were described over 10 different findings in both physical examination and subjective symptoms categories what proves the heterogeneity of the disease presentation.
AHR was described in 40 % of individuals. Tachycardia is in studies a very frequent finding as in this examined group (20 %). Unlike other studies, this study did not record any case of ventricular fibrillation and it showed even a lower representation of LBBB, even though it is a frequent finding even in ICM (up to 20 %, [29]). The most frequent findings were the changes in ST-T which were present in 63 % what together with the chest pain belongs to the basic symptoms of a heart attack what greatly complicates the diagnosis of myocarditis. Ischemic heart disease is excluded just with the use of selective coronarography which underwent majority of adult patients with the definitive diagnosis of myocarditis. Just in this examined group, 10 from 14 patients with elevation of ST segment underwent selective coronarography. However, it is an examination necessary for the exclusion of the diagnosis of acute myocardial infarction which is in adult patients more frequent cause of the heart dysfunction than myocarditis.
ECHO findings were also highly variable. Pericardial effusion was present just in 10 % of cases what corresponds with other studies´ results where the prevalence was sometimes even lower [166]. The most frequent finding of the examined groups was a disorder of the LV kinetics in 14 patients (47 %) including 11 cases of the diffuse character of the kinetics disorder. Systolic function was decreased in 33 % of individuals what corresponds with other studies and proving that myocarditis is not excluded even by normal ECHO findings which had in the Banka et al. study even over 50% percentage [166]. Paradoxically, the SD did not have to associate with higher troponin I levels, for example, 3 of 4 patients with severe LV SD were categorized in Trop I –. A patient with possibly the most severe course of myocarditis with the minimal LV EF just 17 % had initial troponin I level just 0,016 ng/ml and the maximum of troponin I level during the whole hospitalization was just 0,35 ng/ml. However, level of BNP was increased in her case many times even up to 645 pmol/l, even though troponin I was many times described as a predictor of worse prognosis. On the other hand, it is documented that troponin is increased during myocarditis just in 30–50 % of patients [43]. The explanation of this issue is thus quite complicated. In the above-mentioned case, the patient´s state of health could be influenced even by a minor pulmonary embolism verified by CT of lungs and by the finding of 2 thrombi in the left ventricle what could be one of the complications of myocarditis. At the same time, LGE in the area of the septum and inferior wall of the left ventricle was present in this case.
The examined group contained even patients with troponin I level exceeding 10 ng/ml who had normal LV EF and mild SD proving that ECHO is in case of myocarditis more rather a tool of the observation of the patient´s state of health and of the exclusion of other causes of the heart dysfunction than a diagnostic tool for myocardial inflammation [8, 24, 96, 98, 99, 100].
X-Ray was performed in the half of the examined group, mostly with normal finding and thus did not prove any beneficial effect for the diagnosis of myocarditis.
On the other hand, CMRI is recently the leading non-invasive diagnostical method of myocarditis when LGE is used for the detection of the myocardial necrosis or fibrosis. Active inflammation is further supported by the presence of myocardial oedema. In the study from 2012, LGE prevalence was 53 %, however, in other studies, it was even over 80 % [27, 166, 167]. In this study, LGE was present in 67 % of examined subjects (n = 12), whereas 4 patients had at the same time myocardial oedema. In remaining patients with LGE, myocardial oedema did not have to be present if the CMRI was performed in the later phase of the disease.
The main indicator of the myocardial necrosis is troponin which was proved to be an indicator of a worse prognosis and its levels were elevated in the studies in 30 to 50 % [43]. For example, in a study from 2012, its level was elevated just in 23 % of patients [27]. The prevalence of increased troponin I in the examined group was 77 %. In the examined group, troponin I level did not have to correspond with the severity of the clinical state. It may be explained in some patients by a lower extent of the myocardial inflammation and necrosis so the levels of troponin I were not increased so appreciably, or the determination of troponin I was performed with a distinct delay from the initial myocardial damage as a result of myocarditis. Creatine kinase was elevated in 63 % of patients and its myocardial form CK-MB in 2/3 of patens. Together with troponin, it was thus a frequent biomarker of the myocardial damage even though in studies, its level was increased in just 2 % [26, 111, 112]. Myoglobin did not show to be such a reliable biomarker, elevated in just 36 % of patients (n = 22).
From biomarkers of an inflammation/infection, CRP was elevated most frequently (in 80 % of cases), mostly in Trop I + group. In 3 patients, even D dimers examination was positive. In two of them, selective coronarography was performed, first with negative findings on coronary arteries and the second one with stenosis of RIA up to 50 %. In this case, even thrombus in the LV was detected by ECHO. In the last case, selective coronarography was not performed, however, the finding of a thrombus was described during ECHO examination and even by CMRI with positive LGE on non-ischemic myocardial damage. In this case, even minor embolization was shown by CT of lungs. These and other biomarkers are described in more details in the comparison of Trop I – and + groups.
When comparing the groups Trop I – and +, the age of patients reached statistical significance level when patients in Trop I – were older. From subjective symptoms, chest pain reached statistical significance level, when chest pain was stated by just one patient in Trop I – group. However, it is interesting that 2 from 4 cases of heart failure were categorized in Trop I – group. In one case, dilatation of all heart chambers connected with moderate tricuspid regurgitation and severe mitral regurgitation and severely depressed LV systolic function was documented. Another case was evaluated as biventricular heart failure with dilated LV and decreased LV EF and severe tricuspid regurgitation when RV diameters were preserved and there were no signs of its volume or pressure overload. In this case, CMRI proved several LGE areas in both the left and right ventricle. The finding of both regurgitations (even severe) were already reported in myocarditis [104, 105, 106]. At the same time, both patients had in anamnesis no valvular or any other disease which could cause the regurgitation (for example infectious endocarditis etc.). One of the cases of the heart failure in Trop I + has already been described. In the last case of the heart failure, severe systolic dysfunction with LV EF 30 % and dilated LV was proved.
The comparison of ECG findings in Trop I – and Trop I + showed an interesting result, where the characteristic AHR reached statistical significance with the prevalence in Trop I –. 6 from 7 patients in Trop I – had some of the defined AHRs including two cases of atrial fibrillation. The statistical significance level was almost reached even by the characteristic of ST elevation, which was documented just in 1 patient from Trop I – in comparison with 13 patients from Trop I +.
In 4 patients from Trop I –, LV dilatation, kinetics disorder and systolic dysfunction (in 3 patients assessed as severe) was documented. 5 patients from this group had LV EF under 55 %. Differences in X-Ray and CRMI results, unfortunately, were not suitable for statistical evaluation because of a small number of patients in Trop I – group.
In laboratory results, high statistical significance was reached in levels of CK-MB and CRP with significant predominance in Trop I +. In 2 patients from Trop I –, the level of troponin I positive elevated slightly in the course of the hospitalization, however not significantly. In some patients, the explanation is that they could suffer from a mild form of myocarditis what is supported by the fact that CRP was elevated (until 28 mg/l) in just 3 patients from Trop I –. It increased lately in 1 patient. Leucocytosis was in the course of the hospitalization increased in just two patients. Another possible explanation is that patients arrived in the hospital after a longer period of time when the elevation of troponin and biomarkers of inflammation was not so significant. One other explanation of the issue with troponin I level may be even the characteristics of myocarditis itself as a strongly heterogeneity disease with an unpredictable course and prognosis when troponin does not have to be elevated even in up to 50 % of patients. In the question of the increased level of troponin I, we could make a conclusion that the initial troponin I levels do not have to correspond with the severity of a patient´s clinical state proving the complicated character of the disease. This corresponds with the results of a study of children patients with myocarditis where no statistical significance was proved when comparing troponin I levels in fatal cases and recovered children [110]. By contrast, higher troponin I levels were recorded in recovered children – for comparison, the highest initial troponin level in survivors was 39,0 ng/ml and in latent cases 8,8 ng/ml.
Because of the results of this study [110], where AST and creatinine levels were statistically significant predictors of mortality, they were evaluated even in this study. However, they did not reach the statistically significant level even though it almost reached it. Generally, ALT levels were higher in Trop I – and AST levels lower.
This retrospective study has, of course, its limitations. Firstly, it is a limited number of individuals in the examined group, primarily in Trop I – which was for example in the case of X-Ray and CMRI insufficient for the statistical evaluation. However, most of the studies with myocarditis deal the same problem what is caused by a small number of diagnosed cases which is then decreased even by exclusion criteria (in this study it was over 70 patients). It is beneficial to confirm all results in multicentric studies with larger examined groups what is difficult.
A disadvantage is also the fact that prognosis and disease progression after the hospitalization could not be researched because of the reason that a part of patients were foreigners which were further examined abroad or Czech patients were mostly examined in their hometowns.
Nevertheless, despite the limitations, the retrospective study brought relatively interesting results and all of the tree aims were fulfilled. A strong heterogeneity of the disease was proved and demonstrated on a specific group of patients and corresponded with the results of other performed studies.
Author of the opening picture: OpenClipart-Vectors
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