Key result
Apical takotsubo syndrome is linked to ~9-point lower initial LVEF than variant forms.
Why the study?
It is not known how the risk of QTc prolongation and derangement of other markers differ across the echo variants of takotsubo syndrome.
Observational (n=222)
Blinded outcome assessment
No
Absolute Event Rate: 35% vs 44%
p-value: p=<0.0001
Apical takotsubo may signal greater acuity; leaves open whether phenotype-specific risk stratification improves outcomes.
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.
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Watson et al. (2019) conducted an observational in Takotsubo syndrome (n=222). Apical form of takotsubo syndrome vs. Variant forms of takotsubo syndrome was evaluated on Ejection fraction, peak troponin and QTc interval (p=<0.0001). Patients with the apical form of takotsubo syndrome had a lower initial left ventricular ejection fraction (35% vs 44%, p<0.0001) and higher peak troponin than those with variant forms.
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