The majority of firefighters who die from cardiac arrest while on duty have underlying coronary heart disease (CHD) and an enlarged heart, including left ventricular hypertrophy, according to a study of autopsy data published in the Journal of the American Heart Association.
Sudden cardiac death (SCD) is the most common cause of mortality among on-duty firefighters, outpacing blunt force trauma, burns and smoke inhalation.
“Firefighters face many dangers, but the greatest risk is from underlying cardiovascular disease in combination with the physiological strain that the work places on the firefighter,” lead study author Denise L. Smith, PhD, director of the First Responder Health and Safety Laboratory at Skidmore College in Saratoga Springs, New York, said in a press release. “Medical screening is necessary to establish that a firefighter is healthy enough to do this strenuous work.”
Smith et al. studied autopsy data from 276 male firefighters who died of cardiac causes while on duty between 1999 and 2014. They compared those results to 351 firefighters who died of noncardiac, trauma-related causes over the same timeframe.
After multivariable adjustment, a heart weight of more than 450 grams (cardiomegaly) and a previous myocardial infarction were each associated with about six times the odds of dying from cardiac arrest rather than a noncardiac cause. Coronary artery stenosis of at least 75 percent was linked to a 9.3-fold risk of cardiac death.
Among all cardiac fatalities, 82 percent of the men had both CHD with greater than 75 percent stenosis and cardiomegaly/left ventricular hypertrophy.
“It is notable that SCD is the first manifestation of the disease in as much as 50% of all SCDs due to CHD,” the authors wrote. “Given the substantially higher risk of cardiac death associated with CHD and cardiac enlargement, screening measures to detect cardiac enlargement and CHD among firefighters are critical to reduce cardiac deaths in the fire service.”
Firefighting-specific stressors may raise the likelihood that someone at risk of SCD actually suffers an event, the researchers noted. These stressors include strenuous physical activity, heart stress and dehydration, which could lead to ischemia, electrolyte disturbances or ventricular wall stress—triggering a cardiac event.
In addition to more complete cardiac screening of firefighters, Smith and colleagues suggested taking “actionable measures” to lower the risk of cardiac death when CHD or an enlarged heart is detected. The American Heart Association recommends following the Life’s Simple 7 habits: controlling blood pressure and cholesterol, reducing blood sugar, exercising regularly, maintaining a healthy weight and diet and avoiding smoking.
“The increased risk of sudden cardiac death should be carefully considered before medically clearing firefighters for duty or return to duty following a cardiac event or significant cardiovascular procedure,” Smith et al. wrote.
Daniel joined TriMed’s Chicago editorial team in 2017 as a Cardiovascular Business writer. He previously worked as a writer for daily newspapers in North Dakota and Indiana.