TCTMD: On-Duty Firefighter Deaths Are Increasingly Cardiac in Nature
TCTMD recently interviewed Alan Kwan, MD, assistant professor of Cardiology in the Smidt Heart Institute at Cedars-Sinai, about a Cedars-Sinai-led study showing that heart-related conditions account for a growing share of on-duty firefighter deaths, often related to an enlargement of heart muscle mass that can disrupt heart rhythms.
In the study, published in JACC: Advances, investigators analyzed 3,401 on-duty firefighter deaths between 1990 and 2025. From 1999 to 2019, overall on-duty fatalities declined, yet the odds of a heart-related death rose by 2.2% annually—even as cardiac deaths in the general population decreased.
Among 282 firefighter autopsies, 88% were cardiac related. Heart muscle enlargement appeared in nearly 80% of cases and grew significantly over time, frequently accompanying dangerous heart rhythms—even without obstructive coronary artery disease, the narrowing of arteries that typically causes heart attacks.
Kwan, the study’s senior author, told TCTMD he was surprised that heart muscle thickening and hazardous heart rhythms increased among on-duty deaths while standard artery disease remained steady.
“This may be suggesting a change in the phenotype that puts firefighters at risk of on-duty sudden cardiac death,” he said, referring to a possible new pattern of enlarged heart muscles among this group.
Kwan told TCTMD the study was sparked by questions following the January 2025 Palisades and Eaton fires in Los Angeles, as researchers sought to understand the effects of breathing in smoke containing toxic compounds from burned materials.
“The compositions of fires have changed as well, with more what we call wildland-urban-interface fires,” he said. “There's these types of fires that spread very quickly but also have pretty potentially toxic compounds.”
Kwan told TCTMD that researchers must now determine what is causing heart muscle enlargement. Potential factors include toxic exposures, high blood pressure, physical strain, disrupted sleep, and limited access to healthy food at fire stations. To investigate further, Kwan’s team has launched a study tracking more than 1,500 firefighters over time.
“I do think that there’s an increasing need and concern for optimizing firefighter health,” Kwan said, adding he hopes the study’s findings also benefit the broader population—especially as wildfires become more common.
Read the complete article from TCTMD.