Dear editor: The first patient with Covid-19 in Mexico was detected in late February 2020 and the Mexican government implemented measures to decrease the spread of SARS-CoV-2 infection. In order to describe the impact of coronavirus disease 2019 (Covid-19) outbreak in patients with acute myocardial infarction (AMI) in a university hospital in Mexico City, we compared the number and management of patients hospitalized for AMI (ST-segment elevation myocardial infarction [STEMI] or non-ST-segment elevation myocardial infarction [NSTEMI]) during the Covid-19 outbreak (10 weeks, from March 23 to May 31, 2020) with those in the 12 weeks before the pandemic (from January 1 to March 22, 2020) and in the same 10 weeks of the previous year, 2019 (from March 23 to May 31, 2019).

A total of 513 patients with AMI were included (STEMI, 349; NSTEMI, 164). A comparison of the periods before and after the lockdown began on March 23, 2020 showed that hospitalizations for AMI declined by 42.5% during the lockdown (10.8 patients per week vs. 18.8 per week before the lockdown) and by 39.6% (10.8 vs. 17.9 patients per week, respectively) compared with the same period in 2019 (figure 1A). The proportion of STEMI patients who did not receive reperfusion therapy was higher; furthermore, primary percutaneous coronary intervention reperfusion therapy decreased significantly (47.2% during the pandemic vs. 92.8% prior to the pandemic and 96.0% in 2019), while the administration of fibrinolytic therapy increased substantially (52.8 vs. 7.2 and 4%, respectively) (figure 1B). In patients with NSTEMI, the same pattern was observed (figure 1C).¹

AMI: acute myocardial infarction STEMI: ST-segment elevation myocardial infarction NSTEMI: non-ST-segment elevation myocardial infarction

Figure 1 A) A comparison of the numbers of patients hospitalized weekly from January 1 to May 31 in 2019 and 2020. B) The number of admissions per week for acute myocardial infarction. C)Characteristics of reperfusion therapy for STEMI patients hospitalized in the 12 weeks prior to the start of a lockdown (January 1 to March 22, 2020), patients hospitalized during the 10 weeks after the start of the lockdown, the period of maximum contagion (March 23 to May 31, 2020), and patients hospitalized between March 23 and May 31, 2019. Mexico City, 2020 

Large cities in Europe and the United States have reported similar circumstances and this prompts the question: what has happened to AMI patients and what do we expect in the future?^2,3 Programs for the care of patients with AMI are still being implemented and improved in low- and middle-income countries and there has been a significant increase in the performance of primary PCI.⁴ Unfortunately, with the current Covid-19 pandemic, these achievements could well be reversed. The impact that Covid-19 will have on socially disadvantaged groups with AMI remains unclear; however, we must be prepared for a rise in patients with complications because the lack of optimal AMI care during the pandemic.