Usefulness of myocardial positron emission tomography/nuclear imaging in Takotsubo cardiomyopathy.

Abstract

To analyse and summarize all the articles related to positron emission tomography and Takotsubo cardiomyopathy (TTC). We performed a systematic review of the existing literature on positron emission tomography/nuclear imaging and Takotsubo cardiomyopathy using PUBMED database. We combined search terms such as "takotsubo", "takotsubo syndrome", "myocardial positron emission tomography", "positron emission tomography". All case reports were excluded. The list included only four articles which were reviewed by two independent investigators. It was not possible to undertake a formal meta-analysis because of the heterogeneity of the studies; therefore, we made a narrative synthesis of the collected data. Nuclear medicine techniques can be useful employed in the differential diagnosis of TTC from an acute coronary syndrome (ACS). In fact, transient left ventricular (LV) apical ballooning is a syndrome frequently misdiagnosed as an ACS and can mimic symptoms of myocardial infarction with ST-T segments changes on electrocardiography (ECG), a limited release of myocardial enzyme, mainly reported after sudden emotional or physical stress, and an akinesis or dyskinesis of the left ventricle apex which are completely reversible in a few weeks. In the studies included in this review, nuclear medicine techniques have demonstrated a discrepancy between normal perfusion and a reduced glucose utilization in TTC, commonly known as "inverse flow metabolism mismatch". This suggests that apical ballooning represents a transient metabolic disorder on the cellular level, rather than a structural contractile disease of the myocardium, due to a transient decrease of glucose metabolism that might be related to a coronary microcirculation impairment followed by prolonged myocardial stunning. Nuclear medicine techniques can be usefully used for the diagnosis of TTC and can increase our knowledge of the pathophysiological mechanisms of TTC.