Myocardial edema, interstitial expansion and clinical correlates in takotsubo syndrome: a cardiac magnetic resonance tissue mapping study

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background takotsubo syndrome (TTS) is an acute heart failure syndrome characterized by transient systolic dysfunction, widespread myocardial edema and not trivial rate of in-hospital complications. Tissue mapping by cardiac magnetic resonance (CMR) imaging provides measure of myocardial interstitial expansion. Few studies to date comprehensively examined native T1, T2 and extracellular volume (ECV) quantification by CMR in TTS. Purpose to describe T1 and T2 mapping findings by cardiac magnetic resonance (CMR) imaging in a cohort of TTS patients and control subjects. Methods we performed CMR imaging with native T1 and T2 mapping assessment as well as ECV and late gadolinium enhancement (LGE) imaging in n = 14 TTS patients at a median of 4 (3, 7) days after the acute event. Control group consisted of n = 14 healthy individuals with no known prior acute cardiac events. Extracellular-volume (ECV) fraction estimate was derived from native and post-contrast T1 of myocardium and blood pool corrected for hematocrit as reported in literature. All mapping measurements were performed in the interventricular septum from the mid-short-axis view. Results median age of the study population was 72 years, 84% female. Typical apical ballooning was present in 72% of the patients, atypical in 28%, with median left ventricular ejection fraction (LVEF) of 45%; mid interventricular septum was involved in all patients based on the presence of wall motion abnormalities at hospital admission. Median native T1, T2 and ECV were 1078 msec vs 965 msec, 55 msec vs 47 msec and 29% vs 25% in TTS and controls respectively (p < 0.001 for all). A significant direct correlation was found between T2 and both native T1 and ECV in TTS (r = 0.759, p = 0.002 and r = 0.630, p = 0.018 respectively) but not in controls. Moreover, in TTS patients, native T2 inversely correlated with LVEF as assessed at hospital admission (r=-0.563, p = 0.037), whereas non-significant trends were observed between admission LVEF and both native T1 and ECV. No LGE was detected neither in TTS patients nor in controls. Conclusions myocardial edema, as signified by increased T2, is a prominent feature of TTS, likely driving interstitial expansion and increase of native T1 and ECV in the acute phase. Correlation of T2 with LVEF on admission suggests that CMR-based parametric assessment of myocardial edema could contribute to better characterize disease severity in TTS.