Once this protective mechanism is reduced through the decreased production of estrogen after menopause, there is thought to be an increase in endothelial dysfunction predisposing an individual to vasoconstriction and cardiac ischemia. An inciting stressful event elicits the release of catecholamines into the blood stream to create increased heart muscle activity and metabolism. This leads to further cardiac microvascular endothelial dysfunction through oxidative stress, alteration of ion-mediated channels, and electrolyte disturbances which ultimately alter myocardial cell membrane permeability and dysfunction. Coupled with direct heart muscle toxicity, this crescendo of factors are implicated in the ballooning and heart failure characteristically seen in TTS.A 2019 case involved a 60-year-old woman presenting with Takotsubo cardiomyopathy due to over-consumption of wasabi, mistaking it for avocado. Diagnosis
Several well regarded institutions of medical research have produced clinical criteria useful in diagnosing TTS. One of the first sets of guidelines was initially published in 2004 and again in 2008 by the Mayo Clinic. Other research institutions proposing diagnostic criteria include the Japanese Takotsubo Cardiomyopathy Study Group, Gothenburg University, Johns Hopkins University, the Takotsubo Italian Network and the Heart Failure Associates TTS Taskforce of the European Society of Cardiology. All of the research institutions agree on at least two main criteria needed to accurately diagnose TTS: 1) transient left ventricular wall motion abnormality and 2) the absence of a condition obviously explaining this wall motion abnormality (coronary artery lesion, hypoperfusion, myocarditis, toxicity, etc.).
A 2009 large case series from Europe found that takotsubo cardiomyopathy was slightly more frequent during the winter season. This may be related to two possible/suspected pathophysiological causes: coronary spasms of microvessels, which are more prevalent in cold weather, and viral infections – such as Parvovirus B19 – which occur more frequently during the winter. Sex
Women, specifically postmenopausal women, are at greatest risk of developing TTS. This has led some researchers to theorize about the possible protective effects of estrogen in preventing TTS. Genetic risk factors
It is currently being investigated if certain genetic traits associated with catecholamine receptors found on cardiac muscle cells play a role in the development of TTS. There is limited evidence tying TTS directly to a specific genetic expression or mutation, however there is currently a widely held hypothesis supporting the idea of the interaction between environmental factors and the interplay of genetic predisposition leading to the susceptibility to microvascular alterations that contribute to the TTS disease process. Hormonal dysregulation
Certain endocrine diseases including pheochromocytoma and thyrotoxicosis have been identified as potential risk factors for TTS. The relationship between thyroid function and stress cardiomyopathy is marked by a dual phenotype, where both impending primary hyperthyroidism and a high set point of thyroid homeostasis (encoding type 2 allostatic load) are common phenomena. A multi-centre observation study found normal thyroid function to be the exception rather than the rule in TTS. Especially hyperthyroidism is highly prevalent in takotsubo cardiomyopathy, and it seems to predict a poor prognosis in terms of complications and mortality.