Atrial fibrillation is more than an irregular heart beat

A-Fib is the most common cardiac rhythm disturbance and failing to treat it properly could result in a stroke


Updated October 27, 2016

By Dr. Ken Lavelle, MD, NREMT-P

If it wasn't for the weather, it would have been a fairly typical attic fire. But with the temperatures near 90 F and the humidity over 70 percent, just walking around was exhausting. EMS Crews were performing fireground rehab efficiently, although we were noting a large number of firefighters with high heart rates and blood pressures.

An experienced firefighter/EMT was evaluating an individual and called out "Hey Doc!"

Never good to hear in that tone.

"His heart rate is real fast and irregular." The patient (he became a patient once he had an abnormality) was a fairly healthy 56-year-old male. He felt mildly dizzy, but had no chest pain or palpitations (sensation of his heart beating). He was a little flushed, but otherwise looked like most other firefighters on the fireground. Then we hooked up the monitor.

The first look showed the 3-lead as clearly very fast (close to 200) and irregular, consistent with a rhythm called Atrial Fibrillation. He reported he has no history of this ever happening before (that he knows of).

I advised the paramedic to perform a 12-lead EKG, start an IV and start fluids, while I explained to the firefighter what was happening.

What is atrial fibrillation?
Each side of the heart is made up of two chambers — the upper atria and the lower ventricles. The ventricles do the bulk of the work, but the atria are important in priming the pump or making sure that the ventricles are filled with blood so when they contract, a good volume of blood is pumped out.

In Atrial fibrillation, the top part of the heart just quivers — no blood volume is pumped by them so the ventricles are not primed. This causes a loss of about 30 percent of the normal cardiac output. In a younger patient, this may not be too big of a deal. In an older patient it can cause problems from decreased blood supply.

Atrial fibrillation is the most common cardiac rhythm disturbance and its prevalence increases as one ages. It is present in up to nine percent of people in their 80's. The most significant concern is the risk of a stroke because the blood in the atria is not moving well. As it is stagnant, it may form a clot, which could go to the brain. For this reason, many patients that are in AF and stay in the rhythm are on a blood thinner called warfarin.

The signs and symptoms of atrial fibrillation include: 

  • Palpitations
  • Fatigue
  • Lightheadedness
  • Dyspnea on exertion, especially when the rate is fast 

Because the rate of quivering is very fast, electric signals may also reach the ventricles at a rate greater than normal, causing the ventricular rate, or pulse, to be faster than normal. When this occurs, the ventricles cannot fill with blood as well so it is like a "double hit" of inadequate filling — due to the loss of the atria and also the fast rate.

What causes atrial fibrillation?
Hypertension and an enlarged heart can be a cause, or a metabolic issue that causes an increase in the response of the sympathetic nervous system can also be a contributing factor. Sometimes the electrical wiring is just off.

In the case of our firefighter, likely a combination of dehydration, elevated body temperature (which increases the heart rate in anyone) and increased sympathetic nervous system response at the working fire contributed to his AF.

How to treat atrial fibrillation? 
Sometimes in a patient that has a rapid AF, medication is indicated to slow the heart rate. But in this case, since there were other contributing (and potentially reversible) causes, I advised the paramedic to treat those causes first and hold off on the medication. He was stable and had no chest pain or shortness of breath.

We moved him to the ambulance, partially to initiate cooling, but also to get him out of sight of other firefighters. If a firefighter sees his buddy on a stretcher being aggressively treated by EMS, how can it not affect their performance? So, out of sight is out of mind. We notified the incident commander and his company officer. The paramedic started an IV and started a fluid bolus of normal saline — this would provide both hydration and cooling. Then, we simply transported and observed.

Sometimes in medicine we feel we need to do too much. In the emergency department I use a phrase all the time — "Don't just do something, stand there." The patient was stable and improving — his heart rate was down to 150 before he left for the hospital. Initiate a few treatments and then see how he does.

This firefighter did well. He converted back to a normal rhythm with the measures we implemented and that were continued in the hospital. He will follow up with a cardiologist to determine if anything else needs to be done. It is ultimately up to the department's occupation medicine physician, but he can likely return to duty, with counseling on better hydration and earlier rehab.

This case was a good example of why every firefighter, even with minimal or no symptoms, needs to go through rehab at a major incident, especially if the weather or other conditions are unusual. It is also important to assess vitals at the beginning of rehab. The firefighter/EMT did an excellent job with good old fashioned physical assessment, and a potentially life threatening (although unlikely) condition.

About the author
The Albert Einstein Medical Center is a teaching hospital offering a full range of advanced health services to the Philadelphia community and beyond. The center has more than 600 primary care doctors and specialists on staff, with an additional 1,200 affiliated physicians. The Department of Emergency Medicine at the center has staff trained in emergency medical services, special operations medicine, and disaster management. Ken Lavelle is an attending physician at Albert Einstein, and previously spent 14 years working as a firefighter and EMS provider. He serves as medical director for several agencies in Pennsylvania and New Jersey.

 

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