In the first 90 days after the Palisades and Eaton fires erupted in January, the caseload at Cedars-Sinai Medical Center’s emergency room looked different from the norm.

There were 46% more visits for heart attacks than typically occured during the same time period over the previous seven years. Visits for respiratory illnesses increased 24%. And unusual blood test results increased 118%.

These findings were reported in a new study published Wednesday in the Journal of the American College of Cardiology. The study, part of a research project documenting the fires’ long-term health effects, joins several recent papers documenting the disasters’ physical toll.

While other U.S. wildfires have consumed more acres or cost more lives, the Palisades and Eaton fires were uniquely dangerous to human health because they burned an unusual mix of materials: the trees, brush and organic material of a typical wildfire, along with a toxic stew of cars, batteries, plastics, electronics and other man-made materials.

There’s no precedent for a situation that exposed this many people to this kind of smoke, the paper’s authors said.

“Los Angeles has seen wildfires before, it will see wildfires again, but the Eaton fire and the Palisades fire were unique, both in their size, their scale and the sheer volume of material that burned,” said Dr. Joseph Ebinger, a Cedars-Sinai cardiologist and the paper’s first author.

The team did not find a significant increase in the overall number of visits to the medical center’s emergency room between Jan. 7, the day the fires began, and April 7. The department recorded fewer in-person visits for mental health emergencies and chronic conditions during that time compared to the same time period in earlier years, said Dr. Susan Cheng, director of public health research at Cedars-Sinai and the study’s senior author.

The increase in visits for acute cardiovascular problems and other serious sudden illnesses made up the difference.

The study team also looked at results from blood tests drawn from patients visiting the ER for serious physical symptoms without immediate explanation — dizziness without dehydration, for example, or chest pains not caused by heart attacks.

Their blood tests returned unusual results at a rate more than double that seen in previous years. These atypical numbers cut across the spectrum of the blood panel, Cheng said. “It could be electrolyte disorder, change in protein levels, change in markers of kidney or liver function.”

The rate of unusual test results held steady through the three-month period, leading the team to conclude that exposure to the fires’ smoke “has led to some kind of biochemical metabolic stress in the body that likely affected not just one but many organ systems,” Cheng said. “That’s what led to a range of different types of symptoms affecting different people.”

Joan Casey, an environmental epidemiologist at the University of Washington who was not part of the Cedars-Sinai team, noted that the study found health effects lasting over a longer period than similar studies have.

Three months “is a substantial length of time to observe elevated visits, as most studies focused on acute care utilization following wildfire smoke exposure find increased visit counts over about a weeklong period,” Casey said. Her own research found a 27% increase in outpatient respiratory visits among Kaiser Permanente Southern California members living within 12.4 miles of the burn zones in the week following the fires.

“The L.A. fires were such a severe event, including not only smoke, but also evacuation and substantial stress in the population, that effects may have lingered longer,” Casey said.

Thirty-one people are known to have died as a direct result of injuries sustained in the fires. But researchers believe that when taking into account deaths from health conditions worsened by the smoke, the true toll is significantly higher.

A research letter published earlier this year in the Journal of the American Medical Assn. calculated that there were 440 excess deaths in L.A. County between Jan. 5 and Feb. 1. That paper looked at deaths caused by a variety of factors, from exposure to air pollution to disrupted healthcare as a result of closures and evacuations.

On Tuesday, a team from Stanford University published itsprojection that exposure to the fires’ smoke, specifically, led to 14 deaths otherwise unaccounted for.

Wildfire is a major source of fine particulate pollution, bits measuring 2.5 microns or less in diameter that are small enough to cross the barriers that separate blood from the brain and the lungs’ outer branches.

Compared with other sources, wildfire smoke contains a higher proportion of ultrafine particles miniscule enough to penetrate the brain after inhalation, Casey told The Times earlier this year. The smoke has been linked to a range of health problems, including dementia, cancer and cardiovascular failure.

In the last decade, increasing numbers of wildfires in Western states have released enough fine particulate pollution to reverse years’ worth of improvements under the Clean Air Act and other antipollution measures.