Nuclear cardiologic study of Takotsubo cardiomyopathy

Transient left ventricular apical ballooning syndrome, also known as Takotsubo cardiomyopathy (TTC) was described for the first time in Japan in the earliest nineties. It represents 1 to 2 % of acute cardiac events and mimies closely acute myocardial infarction. The aim of this study was to investigate Tc-99m-tetrofosmine or (201)Thallium myocardial Single Photon Emission Computed Tomography (SPECT), I-123-metaIodoBenzylGuanidine (I-123-mIBG) myocardial SPECT and myocardial Positron Emission Tomography using F-18-fluorodeoxyglucose (F-18-FDG) in patients with TTC, assessing respectively left ventricular perfusion, innervation and metabolism. We studied four patients (three females) with TTC. We performed two weeks after acute phase (Subacute phase) myocardial perfusion SPECT and I-123-mIBG myocardial SPECT for each patient. Two of them underwent myocardial PET with FDG. Then, we assessed left ventricular innervation and metabolism three months (chronic phase I) and more than six months (chronic phase II) after the acute phase. We compared the discrepancies between radionuclides uptake in the left ventricular apical region during a follow-up period of more than six months. In subacute phase, perfusion SPECT was normal for each patient. Conversely, I-123-mIBG SPECT and FDG-PET showed concordant apical uptake defect. This perfusion-metabolism pattern called "inverse flow-metabolism mismatch" is the metabolic state of stunned myocardium. After three months, we found improvement of apical tracer uptake in both FDG-PET and I-123-mIBG SPECT. These findings suggest that TTC is characterized by myocardial apical stunning which is related to a disturbance of cardiac sympathetic innervation. I-123-mIBG SPECT might be useful to diagnose earlier this pathology and to rule out acute myocardial infarction. (C) 2007 Elsevier Masson SAS. All rights reserved.