Despite the ongoing debate about the precise cause of Takotsubo syndrome (TTS), there is growing consensus that coronary microvascular dysfunction (CMD) plays a pivotal role in its pathophysiology. A recent study by Dong et al. has elegantly shown in murine models of CMD that abnormalities in myocardial perfusion can lead to the development of TTS, which is reversible upon restoration of normal perfusion [1,2]. Although data in humans are limited, it also suggests that microcirculation may contribute to the development of TTS. However, most of these studies have relied on non-invasive or indirect methods derived from angiography to assess CMD [3]. In addition, the correlation between CMD and transient left ventricular wall motion abnormalities remains to be elucidated.

Intracoronary thermodilution is used for the invasive diagnosis of CMD. Unlike bolus thermodilution, continuous thermodilution enables direct quantification of absolute coronary flow (Q, in mL/min), microvascular resistance (Rμ, Wood Units), and microvascular resistance reserve (MRR) [4,5]. Our objective was to evaluate CMD in patients with TTS using both bolus and continuous thermodilution techniques, upon hospital admission and at short-term follow-up.