Takotsubo cardiomyopathy is a recently described clinical entity characterized by acute but rapidly reversible left ventricular systolic dysfunction in the absence of atherosclerotic coronary artery disease. There is typically balloon-like asynergy of the ventricular apical region, ST elevation in multiple leads, and minimal elevation of cardiac enzymes. Pathological features of this cardiomyopathy and guidelines for diagnosis have not been fully clarified.To clarify pathological features of Takotsubo (ampulla) cardiomyopathy, and the guideline development process, light microscopical examination was performed 9 autopsied cases, and 15 cases that underwent myocardial biopsy or aneurysmectomy (cases were from several institutes in Japan).Results: 1) Myocardial injury was present, but the incidence was relatively low. Damage of single myocytes or aggregate of single myocytes was observed diffusely throughout the ventricles. 2) Extensive damage of single myocytes included. Lesion were dated based on the following findings: hypereosinophilia, myofibrillar degeneration and myocytolysis. 3) Dated on the following histological findings: hypereosinophilia, myofibrillar degeneration, myocytolysis, cell infiltration → fibroblasts → collagen fibers (fibrosis). 4) The fraction of damaged myocytes was significantly higher in the apical than the basal regions. There was focal myocyte injury, including hypereosinophilia of myocytes, myofibrillar degeneration (contraction band formation), myocytolysis, focal fibrosis, and cell infiltrates. Discussion: The main pathological findings in autopsied hearts from patients with Takotsubo cardiomyopathy was injury of single myocyte that appeared as myofibrillar degeneration and its sequelae. The guideline development process was clarified.
