For more than 20 years, the leading causes of line of duty deaths in the fire service have been attributed to “heart attacks”. The majority of Line of Duty Deaths (LODDs) due to heart attack occurs suddenly and with few or no warning signs. Training exercises accounted for line of duty deaths, with the majority of these LODDs being from heart attacks.
There are several standards and rules that address physical conditioning;
Ø 29CFR 1910.120
Ø 29CFR 1910.134
Ø NFPA 1500 Chapter 8, 8-1
Ø NFPA 1500 Chapter 8, 8-3
Ø NFPA 1582 Standard on Medical Requirements for Firefighters
So with all of these standards and rules why is the number of deaths due to heart attacks so high?
Ninety percent of the cases of firefighters, who have died suddenly, the anatomic abnormality present, were coronary artery atherosclerosis. Some of the hearts had scarring from previous myocardial Infarctions (MI) or heart attacks.
The second element in sudden cardiac death is some sort of transient event that perturbs normal cardiac physiological. When emergency scene operations are taking place, the transient event is assumed to be some effect of exertion. Five years of studies have shown that there is a 5-times greater risk of a myocardial infarction within the hour after heavy exertion than during times of sedentary life activities. Other studies have shown a documented increase of sudden deaths or MIs following natural disasters and in the early morning hours, both situations are when stress is heightened. To those of us involved in the fire service, it is obvious that firefighting related sudden deaths are too frequent, given the small amount of time that is spent in a tour of duty directly engaged in emergency scene operations. Therefore, some effect of emergency scene operations must factor into these deaths. These factors are exertion and stress levels.
The third event associated with most sudden cardiac deaths is an electrophysiological abnormality that triggers an arrhythmia (rhythm disturbance). These occur because of abnormalities in transport of ions across cell membranes, which is the way electrophysiological impulses are propagated. These abnormalities can occur in normal heart muscle that is damaged by a medication or electrolyte imbalance. Electrolyte imbalance is probable for most firefighters after each working incident due to the amount of body fluid lost due to the heat factor of gear. It is not uncommon for firefighters who are engaged in heavy workloads during fire suppression activities to lose consistently a liter of fluid in approximately 20 minute. This is a significant amount that can cause severe electrolyte imbalances if the firefighter is not properly hydrated prior to the incident (most of which are not).
So how do we reduce these line-of-duty deaths? “Sudden cardiac death in the fire service is almost always a manifestation of coronary heart disease. Therefore, fire service instructors and safety officers should incorporate heart disease prevention strategies into the training program of every fire department. There should be special effort to identify the highest risk firefighters, the ones with known coronary disease and especially those with prior myocardial infarctions. They should be cleared for active firefighting duty, only after an extensive cardiology evaluation by a cardiologist who understands the nature of firefighting. Firefighters older than 40 years of age should be evaluated at least annually. Even then, it must be realized that screening tests, such as exercise tolerance tests, are only 60 percent likely to disclose coronary disease in a person with no symptoms. Therefore, common sense must dictate the roles played by older firefighters.