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Background: Myocarditis is an inflammatory disease of the myocardium. In its acute phase it can mimic the symptoms of an acute coronary syndrome, induce life-threatening arrhythmias or cardiogenic shock, while in its chronic phase it can lead to dilated cardiomyopathy and heart failure. However, it’ s a disease that is seriously under-diagnosed clinically and usually too late for any specific treatment protocol. In the last two decades, cardiac magnetic resonance has been recognized as a new non-invasive imaging modality for the diagnosis of myocarditis. We would like to present the first two cases of myocarditis confirmed by CMR at the University Hospital Centre Zagreb. The first case is 27-year old male who presented himself in emergency department as an acute coronary syndrome. Alongside clinically typical chest pain, elevation of cardiac Troponin T (cTnT 4.01), ST elevation of 1– 2 mm in inferior leads, he also had echocardiographicaly verified akinesia of the inferoposterior wall with reduced systolic function (EF 45%) and minimal pericardial effusion. Coronary angiography showed a normal coronary angiogram with a slower filling of the left anterior descending artery. The patient had chest pain for several subsequent days after which the symptoms disappeared. The patient temperature rose to 37.7 C while inflammatory parameters remained normal throughout the whole hospital stay (max. CRP 4.5 mg/L, SE 12 mm/h). On the follow-up echocardiographic study after one month only minimal loss of contractility and improval of systolic function were observed. A cardiac magnetic resonance study was performed since the etiology of the incident remained still unclear. To enhance the detection of pathology on CMR, gadolinium-diethylene triamine pentaacetate (DTPA) was used. Contrast-enhanced CMR analysis showed late enhancement in inferior and lateral segments of left ventricle with mid-wall distribution which are typical for the late stage of myocarditis. The second case is 17-year old boy who came in the emergency department because of the fever, sore throat, chest pain and dyspnea. Elevated levels of the inflammatory parameters (CRP 131.2 mg/L, SE 38 mm/h) and cardiac troponin T (cTnT 1.73 mcg/L) were registered, as well as ST elevation in precordial leeds.Right-sided pneumonia was also observed. Echocardiographic exam showed slightly enlarged left ventricle with impaired systolic function (EF 46– 60%) and reduced amplitudes of the wall motion in the posterlateral region. To confirm the diagnosis of myocarditis, CMR was preformed. Oedema of the posterolateral wall was seen, as well as the patchy distribution of contrast enhancement, mostly in the subepicardial segment. In the control period before discharge echocardiographic test results were normal, with EF 70% and the normal contractility of the myocardium. Conclusion: Different LE pattern was observed comparing the acute and chronic phase of myocarditis with the acute phase showing edema in the affected region of the myocardium, while the chronic phase showed a mid-wall pattern. Discussion: Our results correspond with other published series of myocarditis patients that showed high sensitivity of over 90%. Endomyocardial biopsy with histopathology has been used as the gold standard. However, reliance on the Dallas criteria alone has been shown to give false-negative results and the acquisition of myocardial tissue with a bioptome is a painful and not completely risk-free procedure. CMR allows us a non-invasive highly specific method to detect myocarditis both it its acute and chronic phase. |
