4 - CMRI: How scar analysis broadens differential diagnosis

Description of Clinical Presentation: A 25 year old patient presented with acute chest pain. Five months before he suffered from acute myocarditis  proven by MRI and he developed a left ventricular (LV) apical thrombus. Volumes and global ejection fraction were normal but the apex contracted dyskinetic. After anticoagulation for three months the thrombus was undetectable, thus the NOAK was stopped.

Diagnostic Techniques and Their Most Important Findings:

The patient was admitted under the suspicion of myocarditis recurrence with elevated troponin T (274 ng/l (normal < 14)) and CK (292 U/L (normal < 200)), no signs of inflammation but ST elevation in V1 to V4 in the first electrocardiogram (ECG) at admission. Echocardiography (echo) was performed demonstrating normal global systolic function of both ventricles, the apical dyskinesia was comparable to the former report. In addition, recurrence of a left ventricular apical thrombus was detected (fig 1). Six days later cardiac MRI was performed. Volumes and normal global left and right ventricular function was confirmed, but regional septal and anterior function had deteriorated to hypokinetic. While the previously described T2 values had normalized, ECV of the septal and anterior segments now turned out to be 29% with lower values (21%) in the inferior and lateral wall. Diffuse spots of LGE were verifiable in the septum and apex. In contrast to the previous MRI additional endocardial LGE was detected in septal and anterior parts that were very suspicious of cardiac ischemia (figure 2). Thus the question of thombembolic ischemia (septum, anterior wall) was proposed. The initally detected thrombus  was no longer detectable under anticoagulation (figure 2). Due to this suspicion cardiac catheterization was performed revealing slow flow in the left descending artery and the first septal branches with the suspicion of thrombotic material in the periphery. Left main and circumflex coronary artery were normal. Collaterals from the distal right coronary artery to the septum were obviously verified (figure 3). Additional screening for thrombophilic disorders was performed: anticardiolipin antibodies (IgG) were elevated to 91.1 (normal < 40) U/ml; all other screened parameters (lupus-anticoagulans, lupus ratio; APC resistance; protein C and protein S) were in a normal range. Thus the diagnosis of an antiphospholipid syndrome unknown by this point was made. The therapeutic concept was changed into a longer lasting period of anticoagulation, in this case phenprocoumon was started.
 

Learning Points from this

Case:

1. In acute myocarditis thrombus formation in an undilated LV with normal global function is rare and suspicious for a concomitant thrombophilic disorder. 2. Recurrent chest pain after myocarditis has to be taken seriously. We consider the symptoms together with the diagnostic findings as a thrombembolic event with myocardial ischemia. 3. MRI revealed the key information of the existence of different scar formations based on myocarditis and based on myocardial ischemia.