Figure 1. Diagrammatic representation of the dynamic factors involved in the appearance and disappearance of TTS features. The red line represents the variable state of endothelial dysfunction (ED); an episode starts with borderline ED that worsens in response to some precipitating factor, and then recovers gradually over 1 - 2 days. The blue line indicates the appearance of severe epicardial coronary arterial spasm, which quickly resolves, while left ventricular dysfunction appears. Spastic transient occlusion must resolve in 15 - 60 min if no thrombosis occurs (which is rare). The blue area represents the time course of positive Ach testing (days 2 - 5). Usually, ED recovers to within normal limits on about day 5 (i.e., at the time of negative Ach testing) [20]. TTS: transient takotsubo syndrome.