Takotsubo syndrome cases fell in Sweden during the COVID-19 pandemic, registry study finds

Contrary to what researchers in several other countries have reported, the incidence of Takotsubo syndrome in Sweden dropped during the COVID-19 pandemic, according to a nationwide observational study drawing on the Swedish Coronary Angiography and Angioplasty Registry. The study, published in BMC Cardiovascular Disorders, compared the pre-pandemic period from January 2015 to March 2020 with the pandemic period from April 2020 to December 2022, and found that the incidence of the syndrome was 10 percent lower during the pandemic, with an incidence rate ratio of 0.90 (95 percent confidence interval 0.84–0.97, P = 0.008) after adjustment for age and sex.

Takotsubo syndrome is a condition in which the heart muscle weakens suddenly, often triggered by intense emotional or physical stress, and its symptoms closely resemble those of acute myocardial infarction and heart failure. Because the pandemic produced unprecedented psychological, social, and economic stress, many researchers expected the condition to become more common. Earlier studies, however, relied on single-center or multicenter data and lacked the scope to provide national-level insights, which the Swedish team sought to address by covering an entire country across two distinct periods.

The researchers identified 3,180 patients hospitalized with Takotsubo syndrome during the study period. Of these, 69 percent, or 2,189 patients, were treated before the pandemic, while 31 percent, or 991 patients, were hospitalized during the pandemic years. All patients included in the incidence analysis had been referred for coronary angiography in Sweden, and the team calculated incidence rate ratios before and during the pandemic using quasi-Poisson regression adjusted for age and sex.

Mortality did not change between the two periods. The cohort’s crude all-cause mortality rate was 2.73 percent at 30 days and 6.10 percent at one year. After multivariable Cox proportional hazards regression, which accounted for clustering within hospitals, there was no significant difference between the pandemic and pre-pandemic periods at either 30 days, with an adjusted hazard ratio of 1.12 (95 percent confidence interval 0.69–1.78, P = 0.642), or one year, with an adjusted hazard ratio of 1.05 (95 percent confidence interval 0.75–1.46, P = 0.780).

The authors suggest that the reduced incidence of Takotsubo syndrome in Sweden may reflect the country’s comparatively milder pandemic control measures and more robust social security infrastructure relative to other nations. In studies from other countries where incidence increased or remained unchanged, the pattern differed from the Swedish decline over the matching periods, a geographic contrast the study notes without claiming to establish the underlying cause.

As a nationwide observational study, the research describes associations within a single country’s registry data rather than demonstrating causal effects, and the findings apply to patients with Takotsubo syndrome who were referred for coronary angiography in Sweden during the specified periods. The study was published as open access on 29 October 2026 and is reported from the SWEDEHEART registry framework, offering one of the first national-level comparisons of Takotsubo syndrome incidence and mortality across the transition from the pre-pandemic to the pandemic era.

Subject of Research: The incidence and mortality of Takotsubo syndrome in Sweden before and during the COVID-19 pandemic

Article Title: Impact of the COVID-19 pandemic on the incidence and mortality of Takotsubo syndrome in Sweden, a report from the SWEDEHEART registry

Article References: Gudmundsson, T., Petursson, P., Råmunddal, T., Angeras, O., Rawshani, A., Frobert, O., Alfredsson, J., Ekenbäck, C., Henareh, L., Skoglund, K., Ljungman, C., Bollano, E., Mohammad, M., Hagström, H., Jernberg, T., Erlinge, D., Redfors, B., & Omerovic, E. (2026). Impact of the COVID-19 pandemic on the incidence and mortality of Takotsubo syndrome in Sweden, a report from the SWEDEHEART registry. BMC Cardiovascular Disorders. https://doi.org/10.1186/s12872-026-06889-0

Image Credits: AI Generated

DOI: 10.1186/s12872-026-06889-0

Keywords: Takotsubo syndrome, COVID-19 pandemic, SWEDEHEART registry, Sweden, incidence rate, mortality, coronary angiography, stress cardiomyopathy, observational study, epidemiology, Impact, COVID-19