A unique syndrome of heart failure and transient left ventricular systolic dysfunction precipitated by acute emotional or physical stress has recently emerged in the medical literature. The syndrome is referred to by several names, including stress cardiomyopathy, takotsubo cardiomyopathy, left ventricular apical ballooning syndrome, and broken heart syndrome. Because most patients with stress cardiomyopathy present with chest pain, electrocardiographic abnormalities, elevated cardiac enzymes, and focal left ventricular wall motion abnormalities, it is not surprising that for years this syndrome went relatively unrecognized because physicians mistook it for acute myocardial infarction. As reports of this condition have increased worldwide during the past 5 years, it has become clear that stress cardiomyopathy has unique clinical features that can be readily distinguished from those of an acute myocardial infarction. This article reviews the clinical features of stress cardiomyopathy and discusses potential pathophysiologic mechanisms of this disorder.