Takotsubo cardiomyopathy (TK) is a reversible acute left ventricular (LV) dysfunction with a specific pattern that cannot be explained by an obstructive coronary lesion. A stress trigger is commonly found and a summer increase of this pathology has been reported. The potential correlation between heat strokes and TK has not been explored.

The aim of our study is to investigate whether there is a correlation average temperature, number of heat stroke (HS) days and the summer incidence of TK.

This retrospective study is based on patient records of the hôpital du Valais, Switzerland. All acute coronary syndromes (ACS) in this region are referred there. Study period was June 1st until September 30th, from 2012 until 2016. Patients were included if they had an ACS with typical TK echocardiographic anomalies and a normal coronary angiogram (CA). Three groups were established: definite TK (D) if cardiac magnetic resonance imaging (MRI) excluded any other etiology; highly, probable TK (HP) if low probability of a differential diagnosis but MRI was not performed; possible TK (P) if lack of data. Weather data was extracted from the Swiss weather institute registries. A HS day is a day with a temperature above 30°C preceded by 3 days hotter than 30°C.

Three hundred and twenty cases of ACS were reviewed, 43 with normal CA, of which 11 TK: 3 D, 6 HP and 2 P. HS days wise, the hottest year was 2015, then 2016, 2012, 2013 and 2014. We recorded a total of 8 cases of TK in the 2 hottest summers vs. 3 TK over the 2 coolest summers (OR: 2.7). The strongest predictor of TK was the number of HS days. Average summer temperature was less correlated to TK incidence and the amount of rainfall seems to have no impact (Table 1).

Annual variations of the summer incidence of TK seems correlated to the number of HS days rather than just average temperature. Rainfall seems not to be related to the incidence of TK. Those results need to be confirmed on a larger scale.