Ambient Heat Exposure Is Not Associated with Non-ST-Elevation Myocardial Infarction among Emergency Department Patients with Acute Chest Pain

BackgroundHeat exposure increases cardiovascular risk, but its relationship with non-ST-elevation myocardial infarction (NSTEMI) in emergency department (ED) patients is unknown. This study examined whether heat exposure increases NSTEMI risk in ED patients with chest pain.MethodsThis observational cohort study of adults with chest pain from 5 US EDs (April 1, 2019-October 31, 2023) used the Wake Forest Chest Pain Registry. Heat data were collected from the National Oceanic and Atmospheric Administration. Heat exposure was defined as maximum daily heat index ≥80°F, the National Weather Service's cautionary threshold. The primary outcome was index NSTEMI, determined using validated diagnosis codes. Logistic models assessed the association between heat and NSTEMI. Multivariable models were adjusted for common cardiovascular confounders, and pollution-given its potential to exacerbate cardiovascular disease. Lagged analysis evaluated heat exposure over 5-d lags. Unadjusted and adjusted odds ratios (aORs) are reported with 95% confidence intervals.ResultsAmong 21,367 patients with chest pain, 52.7% (11,260/21,367) were female, the median age was 53.5 y (IQR 40-65), and 63.1% (13,486/21,367) had heat-exposed days. Index NSTEMI occurred in 5.9% of patients. NSTEMI rates were similar between those with and without heat exposure (5.8% [778/13,486] vs 6.2% [487/7881]; OR: 0.93, 95% CI 0.83-1.05). After adjustment, heat exposure remained unassociated with index NSTEMI (aOR: 0.91, 95% CI 0.80-1.03). Lagged analysis showed no association between NSTEMI and heat exposure in unadjusted (OR: 0.92, 95% CI 0.82-1.04) or adjusted (aOR: 0.94, 95% CI 0.82-1.07) models.ConclusionHeat exposure was not associated with NSTEMI in chest pain ED patients.