Study Finds Spike in Heart Attacks and Abnormal Labs After L.A. Palisades and Eaton Fires

In the 90 days after the Palisades and Eaton wildfires ignited in January, Cedars-Sinai Medical Center's emergency department saw an unusual shift in the types of patients seeking care. While the overall number of ED visits did not rise, visits for acute cardiovascular events and unexplained serious illnesses increased sharply.

Key Findings

The hospital recorded a 46% increase in visits for heart attacks, a 24% rise in respiratory visits, and a 118% jump in abnormal blood-test results compared with the same 90-day period averaged over the previous seven years. These results are reported in a new study published in the Journal of the American College of Cardiology, part of a larger project tracking the fires' longer-term health impacts.

Unusual Smoke Composition and Systemic Effects

Unlike many wildfires that burn primarily vegetation, the Palisades and Eaton fires consumed large amounts of man-made materials — including cars, batteries, plastics and electronics — producing a highly toxic mix of smoke. The research team concluded the exposures likely caused biochemical and metabolic stress that affected multiple organ systems.

"Los Angeles has had wildfires before and will again, but the Eaton fire and the Palisades fire were distinctive in their size, scale and the sheer amount of material that burned," said Dr. Joseph Ebinger, a Cedars-Sinai cardiologist and the study's first author.

The investigators noted that although in-person visits for mental-health emergencies and many chronic conditions fell during the period (Jan. 7–Apr. 7), the reduction was offset by a rise in acute cardiovascular problems and other sudden severe illnesses. Blood panels from patients who presented with unexplained symptoms (for example, dizziness not caused by dehydration or chest pain not initially attributable to a heart attack) returned atypical results at more than twice the prior years' rate. Abnormalities included electrolyte imbalances, altered protein levels and changes in kidney and liver markers.

Dr. Susan Cheng, director of public health research at Cedars-Sinai and the study's senior author, said the persistently elevated rate of abnormal labs across the three-month window suggests a sustained biochemical stress response in many patients.

Independent experts emphasized the severity and unusual duration of the health effects. Joan Casey, an environmental epidemiologist at the University of Washington, noted that three months of elevated visits is longer than typically documented after wildfire smoke exposure. Other analyses reinforce the wider human toll: one JAMA research letter estimated about 440 excess deaths in Los Angeles County between Jan. 5 and Feb. 1 from various causes linked to the fires and disruptions, while a Stanford team estimated roughly 14 additional deaths specifically attributable to smoke exposure. Thirty-one fatalities have been attributed directly to injuries from the fires.

Why Wildfire Smoke Is Dangerous

Wildfire smoke is a major source of fine particulate matter (PM2.5), particles 2.5 microns or smaller that can penetrate deep into the lungs and enter the bloodstream. Wildfire smoke often contains a higher proportion of ultrafine particles that may cross barriers into the brain and other organs. Research links these particles to a range of health problems, including cardiovascular events, neurological impacts and cancer risk.

The study underscores how increasingly frequent and intense wildfires in Western states are eroding air-quality gains from past decades and creating complex public-health challenges when vegetation burns alongside large volumes of synthetic materials.

Study Source: Journal of the American College of Cardiology. Reporting institutions include Cedars-Sinai; related analyses were published in JAMA and by a Stanford research team.