Seasonal and circadian patterns of myocardial infarction by coronary artery disease status and sex in the ACTION Registry-GWTG.

backgroundMyocardial infarction (MI) presentations are more common during winter months and morning hours. However, it is unknown whether MI with obstructive coronary artery disease (MI-CAD) and non-obstructive CAD (MINOCA) display similar patterns.

methodsWe evaluated seasonal and circadian patterns of MI presentation by coronary artery disease (CAD) status and sex in patients with MI from 2007 to 2014 in the National Cardiovascular Data Registry (NCDR) Acute Coronary Treatment Intervention Outcomes Network (ACTION) Registry-Get With the Guidelines. Adult patients who underwent coronary angiography for MI were included. Patients with missing age, sex, or angiographic data, cocaine use, thrombolytic therapy prior to catheterization, or prior revascularization were excluded. Baseline demographics and characteristics of symptom onset, including season and time of day of presentation, were compared by CAD status and sex.

resultsAmong 322,523 patients, 112,547 were female (35%); 18,918 had MINOCA (5.9%). There was no seasonal pattern of MI overall. However, both men and women with MINOCA presented more often in the summer and fall while MI-CAD presentations were equally distributed across seasons. The most common time of presentation was 8 am-2 pm regardless of CAD status or sex. A secondary peak in women with MINOCA during late afternoon hours was also identified.

conclusionsSeasonal variation of MI differed between MINOCA and MI-CAD, with a small increase in MINOCA incidence in the summer and fall. MINOCA and MI-CAD most commonly occurred in the morning, with a secondary peak in late afternoon in women with MINOCA. These differences in presentation may relate to underlying MI pathophysiology.