Background: Acute myocarditis has a broad spectrum of clinical manifestation from silent conditions to acute coronary syndromes (ACS) or acute heart failure. The mortality rate varies from 15% to 20%, therefore rapid diagnosis is of utmost importance. We present a challenging case initially diagnosed with ventricular tachycardia (VT) and acute myocardial infarction (AMI) in which multimodality imaging approach (echocardiography, coronary angiography, and cardiac magnetic resonance (CMR)) changed the diagnosis, prognosis, and follow-up plan.
Case presentation: A 68-year old woman with dyslipidaemia, known with a previous AMI without ST elevation in the last month with monomorphic VT with apical origin morphology and hemodynamic instability at the onset, was admitted in our department with a new episode of chest pain with abnormal ECG (negative T waves in anterior and lateral leads) without TpI elevation. Previous AMI without ST elevation was diagnosed based on high level of TpI suggestive for myocardial damage, VT, and postconvertion ECG with negative T waves in anterior leads in a centre without angiography facilities. To restore the sinus rhythm an electrical cardioversion was performed. The patient had dual antiplatelet therapy, beta-blockers, angiotensin-converting enzyme inhibitors (ACEI), amiodarone and statins, initiated in the previous hospitalization. She was hemodynamically stable. Echocardiography in emergency department revealed mild systolic dysfunction (LVEF=45%), diastolic dysfunction grade I, without significant valvulopathy, severe lateral wall hypokinesia, no pericardial effusion. The coronary angiography performed during the current admission excluded the presence of significant lesions on all coronary arteries making the diagnosis of ACS questionable. We tried to identify another cause for ventricular arrhythmia. 2D speckle tracking (STE) analysis showed decreased longitudinal myocardial deformation predominantly in the left ventricular (LV) lateral wall, more pronoun-ced in the epicardial layer than in the endocardial one.
There are also small patchy areas of myocardial defor-mation deterioration in the apical part and infero-basal segments of the LV. Moreover, tissue Doppler Imaging (TDI) revealed decreased systolic velocities on the la-teral wall (mostly in the mid part), with an important inter- and intra-ventricular dyssynchrony (90 msec.) and between LV segments. All these findings are inconsistent with coronary artery involvement, suggesting an inflammatory aetiology. Consequently, we performed CMR in order to confirm the myocarditis. CMR revealed an LVEF of 60% and late gadolinium enhancement mostly in mid-ventricular section of the lateral wall suggestive for myocarditis, lateral wall hypokine-sia and intraventricular dyssynchrony consistent with TTE findings. A small pericardial effusion (7 mm) was also found in the inferior part of the LV. In this light we concluded for myocarditis as the aetiology of VT and TpI elevation. Therefore we changed the dual antiplatelet treatment to single antiplatelet therapy, maintaining the beta- blockers, ACEI, statins, and amiodarone. We decided to repeat the CMR after 6 months, in order to decide the best prevention method for a new arrhyth-mic event (medical treatment, implantable defibrillator, VT ablation)
Discussion: Despite the left bundle branch block mor-phology with negative concordance of VT, the CMR did not describe any lesion of the apical region of both ventricles. However, inflamatory process in myocarditis is a difuse process, and CMR for the apical part of a non-dilated RV can not exclude entirely myocardial inflamation. We decided for a six months follow-up using echo and CMR, in order to discover if there is a complete restoration of the inflamatory lesions or fibrosis areas. These aspects might guide the sudden death prevention and prognosis.
Conclusions: This case report highlights the importance of early diagnosis in patients with myocarditis and malignant ventricular arrhythmia. In our case TDI, STE raised the suspicion of myocarditis confirmed by CMR and changed the initial diagnosis of the patient and possible the prognosis.