Microvascular dysfunction/Transient vasospasm: Some of the original researchers of takotsubo suggested that multiple simultaneous spasms of coronary arteries could cause enough loss of blood flow to cause transient stunning of the myocardium.
The text describes a theory about how microvascular dysfunction and transient vasospasm might contribute to takotsubo cardiomyopathy, suggesting that multiple coronary artery spasms can lead to insufficient blood flow, causing temporary heart muscle damage.