Incremental “Therapeutic” Myocardial Exposure to Catecholamines: Incidence and Impact in Takotsubo Syndrome

Blood norepinephrine/epinephrine/dopamine measurements in 108 patients with takotsubo syndrome from the world literature: pathophysiological implications

OBJECTIVES

Release of norepinephrine (NE) from neuronal cardiac nerve endings and/or blood-borne catecholamines (CATs), mainly epinephrine (EPI), may mediate TTS. The aim of this study was to document the levels of NE, EPI, and dopamine (DA) in patients with TTS.

MATERIALS AND METHODS

A qualitative/quantitative meta-analysis of CATs and their relationship to age, gender, and triggers, was carried out, employing the world literature on TTS, published in PubMed.

RESULTS

NE/EPI/DA in108 patients with TTS, 65.2 ± 16.4 years old, 89 (82.4%) women, revealed that: NE was measured more frequently than EPI, and EPI than DA; the timing of the measurements was variable; CATs were reported variably (qualitatively/quantitatively/with/without upper limits of normal); NE/EPI or NE/EPI/DA rose to the same degree; CATs were normal, or mildly/moderately elevated, with only 6 patients showing markedly elevated NE/EP/DA; NE, EPI, and DA were similar in patients with physical triggers and NE was similar in patients with physical, emotional, or no triggers (p = 0.47); EPI was higher than NE in patients with emotional triggers and EPI was higher in patients with emotional than physical triggers (p = 0.012); NE, EPI, and DA rose to the same proportion in men and women; types of TTS triggers were distributed proportionally in men and women.

CONCLUSION

NE, EPI, and DA rise proportionally in patients with TTS; CATs are mildly/moderately, and rarely markedly elevated; measurements of CATs should become more systematised; although CATs may not be essential for TTS diagnosis, they may contribute to prognosis and elucidation of the pathophysiology of TTS.

Incidence and clinical/laboratory correlates of early hypotension in takotsubo syndrome

Aims

Takotsubo syndrome (TTS) is a form of acute myocardial inflammation, often triggered by catecholamine release surges, which accounts for approximately 10% of ‘myocardial infarctions’ in female patients above the age of 50. Its associated substantial risk of in‐hospital mortality is mainly driven by the development of hypotension and shock. While hypotension is induced largely by factors other than low cardiac output, its precise cause is unknown, and clinical parameters associated with hypotension have not been identified previously. We therefore sought to identify the incidence and clinical/laboratory correlates of early hypotension in TTS.

Methods and results

We analysed the in‐hospital data of patients recruited to the South Australian TTS Registry. Associations between the development of hypotension, patient demographics, severity of the acute TTS attack, and key biochemical markers were sought. One hundred thirteen out of 319 patients (35%) were hypotensive (median systolic blood pressure 80 mmHg) during their index hospitalization. Development of hypotension preceded all in‐hospital deaths (n = 8). On univariate analyses, patients who developed hypotension had lower left ventricular ejection fraction (P = 0.009), and higher plasma N‐terminal pro brain natriuretic peptide and troponin‐T concentrations (P = 0.046 and 0.008, respectively), all markers of severity of the TTS attack; hypotension also occurred less commonly in male than in female patients (P = 0.014). On multivariate linear regression analysis, female sex and lower left ventricular ejection fraction were independent correlates of the development of hypotension (P = 0.009 and 0.010, respectively).

Conclusions

Early development of hypotension is very common in TTS, and its presence is associated with a substantial risk of in‐hospital mortality. Hypotension is a marker of severe TTS attacks and occurs more commonly in female TTS patients.

Takotsubo Syndrome: Finally Emerging From the Shadows?

It is now 30 years since Japanese investigators first described Takotsubo Syndrome (TTS) as a disorder occurring mainly in ageing women, ascribing it to the impact of multivessel coronary artery spasm. During the intervening period, it has become clear that TTS involves relatively transient vascular injury, followed by prolonged myocardial inflammatory and eventually fibrotic changes. Hence symptomatic recovery is generally slow, currently an under-recognised issue. It appears that TTS is induced by aberrant post-β₂-adrenoceptor signalling in the setting of "surge" release of catecholamines. Resultant activation of nitric oxide synthases and increased inflammatory vascular permeation lead to prolonged myocardial infiltration with macrophages and associated oedema formation. Initially, the diagnosis of TTS was made via exclusion of relevant coronary artery stenoses, plus the presence of regional left ventricular hypokinesis. However, detection of extensive myocardial oedema on cardiac MRI imaging offers a specific basis for diagnosis. No adequate methods are yet available for definitive diagnosis of TTS at hospital presentation. Other major challenges remaining in this area include understanding of the recently demonstrated association between TTS and antecedent cancer, the development of effective treatments to reduce risk of short-term (generally due to shock) and long-term mortality, and also to accelerate symptomatic recovery.