Acute myocardial infarction (AMI) treatment requires timely diagnosis and treatment for optimal health outcomes. The COVID-19 pandemic has caused changes in healthcare delivery and utilisation; therefore, our study explored the changes in emergency care quality indicators for patients with AMI before and during different periods of government response to the COVID-19 outbreak in Taiwan. The Taiwan Clinical Performance Indicators (TCPI) database was used to evaluate the impact of COVID-19 on acute care quality indicators for patients with AMI during four periods: before the COVID-19 outbreak (Period I, 1 January to 31 December 2019) and during three periods in which the central government imposed different levels of epidemic prevention and response alerts (Period II, 1 January 2020, to 30 April 2021; Period III, 1 May to 31 July 2021; and Period IV, 1 August to 31 December 2021) . A 15.9% decrease in monthly emergency department admission for patients with AMI occurred during Period III. The hospital "door-to-electrocardiogram time being <10 min" indicator attainment was significantly lower during Periods III and IV. The attainment of "dual antiplatelet therapy (DAPT) received within 6 hours of emergency department arrival" indicator improved in Period IV, whereas "the primary percutaneous coronary intervention (PCI) being received within 90 min of hospital arrival" indicator significantly decreased during Periods III and IV. The indicator "in-hospital mortality" was unchanged within our study duration. Overall, the quality of care for patients with AMI was mildly influenced during the assessed pandemic periods, especially in terms of door-to- electrocardiogram times of <10 min and primary PCI received within 90 min of hospital arrival (Period III). Using our study results, hospitals can develop strategies regarding care delivery for patients with AMI during a COVID-19 outbreak on the basis of central government alert levels, even during the height of the pandemic.