Non-optimum temperature exposure may impair cardiac structure and function: A repeated-measure analysis based on...

The impact of ambient temperature on cardiac structure and function is not well understood.

We aim to investigate the relationship between short-term exposure to non-optimal ambient temperature and cardiac structure and function.

We designed a longitudinal repeated-measure study in Shanghai, China from 2014 to 2020 among 127,317 participants who underwent at least two echocardiogram tests. We used linear mixed-effects models and distributed lag non-linear models to assess the associations of ambient temperature with 6 cardiac structural parameters and 4 cardiac functional parameters. Our analysis reveals generally inverse U-shaped relationships between ambient temperature and most cardiac parameters. The effects of ambient temperature on cardiac parameters typically manifested within 5 days of exposure and subsided after about 10 days. Compared with the reference temperatures (approximately 20 °C), extreme low temperature (1 °C) result in a 0.66 % increase in pulmonary artery systolic pressure (PASP), a 1.30 % decrease in S-wave peak (PS), a 0.47 % decrease in the left ventricular ejection fraction (LVEF), and an increase in cardiac structural parameters of 0.05 %-0.61 %. Extreme high temperature (33 °C) result in an increase of 0.56 % in PASP, a decrease of 2.26 % in PS, and an increase of 0.06 %-0.81 % in cardiac structural parameters, and the temperature-induced changes in effect sizes did not differ significantly by gender and age subgroups.

This large-scale study provides new insights into how extreme temperatures could adversely affect cardiac structure and function. Both low and high temperatures have the potential to lead to expanded cardiac morphology and poorer cardiac function.