Takotsubo Cardiomyopathy: A COVID-19 Complication

Phenome-wide association study and precision medicine of cardiovascular diseases in the post-COVID-19 era

SARS-CoV-2 infection causes injuries of not only the lungs but also the heart and endothelial cells in vasculature of multiple organs, and induces systemic inflammation and immune over-reactions, which makes COVID-19 a disease phenome that simultaneously affects multiple systems. Cardiovascular diseases (CVD) are intrinsic risk and causative factors for severe COVID-19 comorbidities and death. The wide-spread infection and reinfection of SARS-CoV-2 variants and the long-COVID may become a new common threat to human health and propose unprecedented impact on the risk factors, pathophysiology, and pharmacology of many diseases including CVD for a long time. COVID-19 has highlighted the urgent demand for precision medicine which needs new knowledge network to innovate disease taxonomy for more precise diagnosis, therapy, and prevention of disease. A deeper understanding of CVD in the setting of COVID-19 phenome requires a paradigm shift from the current phenotypic study that focuses on the virus or individual symptoms to phenomics of COVID-19 that addresses the inter-connectedness of clinical phenotypes, i.e., clinical phenome. Here, we summarize the CVD manifestations in the full clinical spectrum of COVID-19, and the phenome-wide association study of CVD interrelated to COVID-19. We discuss the underlying biology for CVD in the COVID-19 phenome and the concept of precision medicine with new phenomic taxonomy that addresses the overall pathophysiological responses of the body to the SARS-CoV-2 infection. We also briefly discuss the unique taxonomy of disease as Zheng-hou patterns in traditional Chinese medicine, and their potential implications in precision medicine of CVD in the post-COVID-19 era.

Epidemiology, Pathophysiology, Diagnosis, and Principles of Management of Takotsubo Cardiomyopathy: A Review

Takotsubo cardiomyopathy, also known as stress-induced cardiomyopathy, is a reversible syndrome commonly found among patients presenting for acute coronary syndromes, especially women. With the COVID-19 pandemic, the incidence of takotsubo cardiomyopathy was dramatically increased. However, this clinical cardiac entity remains underdiagnosed, largely due to the interplay with acute coronary syndrome. The pathophysiology of takotsubo cardiomyopathy is miscellaneous, including coronary vasospasm, microcirculatory dysfunction, catecholamine surge, and sympathetic overdrive. Diagnosing takotsubo cardiomyopathy requires a high index of clinical suspicion and multimodality tests. To date, there are no guidelines for the management of takotsubo cardiomyopathy. Thus, available data are derived from case series, retrospective analyses, and experts' opinions. Heart failure medicines were investigated in takotsubo cardiomyopathy patients. Evidence supports the benefits of angiotensin-converting enzyme inhibitors and angiotensin receptors blockers use on mortality and recurrence rates, while results from use of beta-blockers are controversial. In complicated cases, inotropes are preferred over vasopressors, except in the presence of left ventricular outflow tract obstruction, in which medical therapy is limited to fluids administration and beta-blockers. Use of oral vitamin K antagonist can benefit patients at high thrombo-embolic risk for up to 3 months. Mechanical supports are reserved for refractory hemodynamically unstable cases. This review aims to provide an update on the epidemiology, diagnosis, and outcomes of takotsubo cardiomyopathy, and an extended discussion on the management of complicated and non-complicated cases.

Hyperthermia as a trigger for Takotsubo syndrome in a rat model

Takotsubo syndrome is a well-characterized cause of acute yet reversible heart failure associated with periods of intense emotional stress, often mimicking on presentation an acute coronary syndrome. Animal models of Takotsubo syndrome have been developed, either through the application of a stressor, or administration of exogenous catecholamine. We found that in a model of isoproterenol-induced Takotsubo syndrome in anesthetized rats hyperthermia (40-41°C) would occur after the administration of isoproterenol. Maintenance of this hyperthermia would result in an apical hypocontractility typical of the syndrome, whereas prevention of hyperthermia with active cooling to maintain a euthermic core body temperature prevented (but did not subsequently reverse) apical hypocontractility. In vitro experimentation with isolated cardiomyocytes showed no effect of hyperthermia on either baseline contractility or contractility change after beta-adrenoceptor stimulation. We suggest that the rise in body temperature that is characteristic of catecholamine storm may be a component in the development of Takotsubo syndrome.