Abstract 3606: Reversible Myocardial Injury, but not Microvascular Obstruction, is Major Pathophysiology of Takotsubo Cardiomyopathy Detected by Contrast-Enhanced Magnetic Resonance Imaging
.Background: Takotsubo cardiomyopathy is a syndrome characterized by transient ST-elevation and left ventricular (LV) apical ballooning in the absence of epicardial coronary artery disease, but the mechanism remains unknown. Because cardiovascular magnetic resonance imaging (MRI) can detect impaired myocardial perfusion, myocardial fibrosis (e.g. myocardial infarction), and myocardial edema, we sought to assess which coronary microvascular obstruction or direct myocardial injury contributes to the pathophysiology of this syndrome.
METHODS: Cardiac cine, T2-weighted images, first pass perfusion (FPP), and delayed enhanced (DE) MRI were performed in 10 patients with Takotsubo cardiomyopathy and 4 age-matched controls. DE-MRI was performed sequentially before and 2, 5, 10, and 20 minutes after Gd-DTPA injection. Cardiovascular MRI was obtained within 1 week for all patients, and follow-up CMR studies were conducted at 3 and 6 months.
RESULTS: All patients with Takotsubo cardiomyopathy underwent emergent cardiac catheterization, which revealed normal epicardial coronary arteries without any evidence of spasm. In Takotsubo cardiomy-opathy patients, there was no hypoenhancement on FPP or hyperenhancement on DE-MRI, indicating absence of microvascular obstruction and infarction. In addition, in the early phase of DE-MRI (2–5 minutes after Gd-DTPA injection), the apical ballooning regions were demarcated as regions of homogenous hyperenhancement, whereas no significant hyperen-hancement was observed in controls. Furthermore, high intensity signals on T2-weighted images reflecting myocardial edema, were observed in the apical ballooning regions. Follow-up cardiovascular MRI demonstrated complete resolution of wall motion abnormalities and the disappearance of the high intensity signals on T2-weighted images and hyperenhancement on DE-MRI in the early phase within 3 months.
Conclusion: On cardiovascular MRI, myocardial edema without infarction and intact microvascular integration are the main pathophysiology of Takotsubo cardiomyopathy. This suggests that the mechanism of acute transient LV dysfunction may be direct myocyte injury but not microvascular obstruction.