Effects of lockdown on acute coronary syndrome incidence in an area without community transmission of COVID-19

Objective: To assess the changes in cardiac hospitalisations, acute coronary syndromes (ACS) and out-of-hospital cardiac arrest (OOHCA) during COVID-19 isolation compared with prior time periods in an area of low COVID-19 disease incidence. Methods: Review of all cardiology admissions, non-ST segment elevation myocardial infarction (NSTEMI), ST-segment elevation myocardial infarction (STEMI) requiring urgent catheter laboratory activation and OOHCA. The 10-week period of government-imposed social isolation (23 March-31 May 2020) was compared with the same period in 2018, 2019 and a 10-week period prior to social isolation (6 January-15 March 2020). Incidence rate ratios were calculated. Symptom to balloon time was also compared for those requiring catheterisation laboratory activation for STEMI. Results: The incidence of COVID-19 in the health district was 0.14 per 100 000 per day during the isolation period. There was a significant reduction in cardiology hospitalisations, NSTEMI and STEMI presentations without changes in OOHCA or symptom to balloon time for STEMI. Conclusions: We observed a significant decline in cardiology presentations during social isolation without widespread COVID-19 disease. This provides further evidence for the important influence of social and behavioural factors on coronary event rates.