Stress (Takotsubo) cardiomyopathy—a novel pathophysiological hypothesis to explain catecholamine-induced acute myocardial stunning

Top Cited Papers
Publisher Website
Google Scholar
Abstract
Stress cardiomyopathy, also referred to as Takotsubo cardiomyopathy, is an increasingly recognized clinical syndrome characterized by acute reversible apical ventricular dysfunction. We hypothesize that stress cardiomyopathy is a form of myocardial stunning, but with different cellular mechanisms to those seen during transient episodes of ischemia secondary to coronary stenoses. In this syndrome, we believe that high levels of circulating epinephrine trigger a switch in intracellular signal trafficking in ventricular cardiomyocytes, from Gs protein to Gi protein signaling via the β2-adrenoceptor. Although this switch to β2-adrenoceptor–Gi protein signaling protects against the proapoptotic effects of intense activation of β1-adrenoceptors, it is also negatively inotropic. This effect is greatest at the apical myocardium, in which the β-adrenoceptor density is greatest. Our hypothesis has implications for the use of drugs or devices in the treatment of patients with stress cardiomyopathy.