Estradiol protection against toxic effects of catecholamine on electrical properties in human-induced pluripotent stem cell derived cardiomyocytes

Comparing the variants of takotsubo syndrome: an observational study of the ECG and structural changes from a New Zealand tertiary hospital

OBJECTIVES

In takotsubo syndrome, QTc prolongation is a measure of risk of potentially fatal arrhythmia. It is not known how this risk, or derangement of other markers, differs across the echo variants of takotsubo syndrome. Therefore, we sought to explore whether apical takotsubo syndrome differs from the variants of the syndrome in more ways than just regional wall motion pattern. As the region of affected myocardium is usually larger, we hypothesised that patients with the classic apical ballooning form of takotsubo syndrome would have more severe derangement of their markers.

DESIGN

Observational study of patients gathered from a prospective database (2010-2018) and by retrospective review (2006-2009).

SETTING

The sole tertiary hospital from a New Zealand region in which case clusters of takotsubo syndrome were precipitated by large earthquakes in 2010, 2011 and 2016.

PARTICIPANTS

A total of 222 patients who met a modified version of the Mayo criteria for takotsubo syndrome were included. All patients had digitally archived echocardiograms that were over-read by a second echocardiologist blinded to the clinical report.

PRIMARY OUTCOME MEASURES

Ejection fraction, peak troponin and QTc interval.

RESULTS

Patients with the apical form were older (p=0.011), had a lower initial left ventricular ejection fraction (35% vs 44%, p<0.0001) and a higher peak high-sensitivity troponin I (hsTnI) (p=0.01) than those with variant forms. There was no difference in the electrical abnormalities between the variants (QTc interval, heart rate, PR interval, QRS duration or T-wave axis). There was also no correlation between any of peak hsTnI, peak QTc and ejection fraction. QTc interval increased on day 2 and peaked on day 3 before falling steeply (p<0.0001).

CONCLUSIONS

The variants of takotsubo syndrome differ in more ways than just their echo pattern but do not differ in their electrical abnormalities. There is a dissociation between the structural and electrical abnormalities. QTc peaks on day 3 and then falls steeply.

Short- and Long-Term Incidence of Thromboembolic Events in Takotsubo Syndrome as Compared With Acute Coronary Syndrome

Thromboembolic events are a common complication in Takotsubo syndrome (TTS). However, their long-term incidence compared with acute coronary syndrome (ACS) is lacking. In-hospital and long-term incidence of thromboembolic events of 138 consecutive patients with TTS were compared with 138 sex- and age-matched patients with ACS. Predictors of events were analyzed. The incidence of thromboembolic events in TTS was 2-fold higher than ACS (21% vs 9%; P < .01) over a mean follow-up of 5 years. Although the left ventricular ejection fraction (LVEF) at event was significantly lower in TTS compared with ACS (38% [9%] vs 54% [11%]; P < .01), the follow-up LVEF was comparable. Patients with TTS suffering from thromboembolic events were more often treated with anticoagulation compared with ACS (44.8% vs 8.3%, P = .03). However, more patients presenting with ACS (100% vs 48.3%; P < .01) were discharged on aspirin. Only elevated C-reactive protein was a predictor of thromboembolic events using multivariate analysis (hazard ratio 1.1, 95% confidence interval, 1.0-1.2; P < .01). In conclusion, the risk of thromboembolic events in TTS was significantly higher than the risk of thromboembolic events in ACS over a mean follow-up of 5 years.

Plasma Epinephrine Level and its Causal Link to Takotsubo Syndrome Revisited: Critical Review with a Diverse Conclusion

Takotsubo syndrome (TS) is a recognized acute cardiac syndrome with a clinical presentation resembling that of an acute coronary syndrome (ACS). The defining feature of TS is the reversible left ventricular wall motion abnormality (LVWMA), which has a unique circumferential pattern resulting in a conspicuous ballooning of the left ventricle during systole, and extending beyond the coronary artery supply territory. The pathogenesis of TS is still elusive and several pathophysiological mechanisms have been proposed. A common portrayal of the syndrome in the literature is that the disease is characterized by massive surge of plasma catecholamines including epinephrine. Based on the assumption of massive plasma epinephrine elevation, some investigators hypothesized that the circulatory plasma epinephrine plays a pivotal role in the pathogenesis of TS. One typical such hypothesis is epinephrine induced switch in signal trafficking causing apical or mid-apical ballooning in TS. In-depth analysis of the literature reveals that no study with certainty has shown "massive" plasma epinephrine elevations in TS. Furthermore, the literature evidences challenging the epinephrine-induced switch in signal trafficking are substantial. In this review, sufficient data, indicating that the plasma epinephrine in TS is either normal or moderately elevated in all studies, are provided. Noteworthy, epinephrine may act as a trigger factor for TS-induction but there is no evidence for a direct causal link between epinephrine and TS.