Jeffrey Tabas, MD, on Rate Control for Patients With Atrial Fibrillation

 

In this podcast, Jeffrey Tabas, MD, discusses rate control among patients presenting with atrial fibrillation as a challenge for emergency department physicians, a topic he discussed during his session at the American College of Emergency Physicians 2021 Scientific Assembly.

For more parts of this series, visit our resource center for the American College of Emergency Physicians 2021 Scientific Assembly.

Additional Resources:

 


Jeffrey Tabas, MD, is a professor of emergency medicine at the University of California, San Francisco’s School of Medicine, an emergency medicine physician at Zuckerberg’s San Francisco General Emergency Department, the director of faculty development for the Department of Emergency Medicine, and the director of Outcomes and Innovations for the UCSF Office of Continuing Medical Education.


 

TRANSCRIPT:

Amanda Balbi: Hello and welcome to a special series of Podcasts360. I’m your moderator, Amanda Balbi. In this 6-part series, we will be speaking with Dr Jeffrey Tabas, who is a professor of emergency medicine at the University of California, San Francisco’s School of Medicine, an emergency medicine physician at Zuckerberg’s San Francisco General Emergency Department, the director of faculty development for the Department of Emergency Medicine, and the director of Outcomes and Innovations for the UCSF Office of Continuing Medical Education.

He recently presenting a session on atrial fibrillation at the American College of Emergency Physicians 2021 Scientific Assembly. In part 2 of this podcast series, he talks about rate control among patients presenting with atrial fibrillation in the emergency department.

Let’s listen in as he answers our questions.

So, one of the main challenges you spoke about was rate control among patients with AFib. Can you tell us a little more about that?

Jeffrey Tabas: What I use is I summarize, a lot of the evidence and recommendations that are provided in the recent society guidelines. In 2019, the American Heart Association and American College of Cardiology and Heart Rhythm Society came out with a focused update on atrial fibrillation guidelines. Then in 2020 the European Society of Cardiology came out with updated guidelines for the diagnosis and management of atrial fibrillation in collaboration with the European Association of Cardiothoracic Surgeon.

The pearls in management of rate control for atrial fibrillation in the emergency department—so if someone's unstable, we need to stabilize them, and if they don't respond to fluids or treatment of the underlying source, we cardiovert them. Usually, we electrically cardiovert them because they're unstable. That's pretty much a basic practice.

I also talked about the approach to a patient who comes in with a fast heart rate. Patients who have fast heart rates, it's not always obvious what the cause is. Really, the first question that we need to ask as emergency providers is, “Is this a regular or irregular rhythm?” If it's irregular, 95% of the time it will be atrial fibrillation. That sounds like an obvious question, but I have seen patients with wide complex QRS who have irregular rhythm, who are who are misdiagnosed as things other than atrial fibrillation.

In addition, patients who are going very fast in which the irregularity is not appreciated, so we do spend some time looking at the pitfalls of trying to measure out whether a rhythm is fast and irregular or fast and regular. And it's very important to look at the R-to-R interval and see if there's any variation, especially when you're going at rates over 150. When there's variation in that R-to-R interval, it's highly likely that you're looking at atrial fibrillation.

Some of the other pitfalls, we discuss a case in which patients had their rate controlled with IV intravenous diltiazem and are then admitted for further stabilization. The patient is someone who is severe alcoholic, and it's unclear if their rates fast, because of the underlying atrial fibrillation, if they have another source, such as pneumonia, or if they're in alcohol withdrawal, or if they're dehydrated.

A lot of times you need to treat for all of these. You need to rehydrate them. Give them fluids. Treat for alcohol withdrawal and control their rate with rate-control agents. Something that's invaluable in the assessment is determining their volume status and cardiac function with bedside ultrasound. That's very helpful in a patient who's going very fast and it's not always clearly just due to uncontrolled atrial fibrillation.

In this case, the patient had their fluids repeated, their electrolytes replaced, and were given Ativan and then their rate was controlled with diltiazem, then they were admitted to the hospital. What happened was the emergency department team did not give an oral rate controller agent or put this patient on an intravenous drip so that the initial dose of diltiazem wore off and their rate went back up. When the admitting doctors came down, they said, “Oh look, they were given diltiazem and it's not working anymore,” as opposed to recognizing the pharmakinetics that it lasts for about 45 minutes, and if you want their rate to be controlled longer than that, you either need to switch them to an oral medication or put them on a drip.

On arrival, the admitting team started IV metoprolol, switched agents. Eventually the patient's blood pressure dropped into the 70s and they needed to be emergently cardioverted because they became unstable. 

Some of the take-home pearls from trying to rate control someone is to always remember that the initial rate control with IV medications is short-acting, and there needs to be a long-acting therapy to continue until that patient’s underlying condition is resolved or they're converted into normal sinus.

In addition, the assessment of a patient in atrial fibrillation can be complicated, so the rate can be fast from dehydration, from alcohol withdrawal, from other causes like sepsis, and it's very helpful to determine their volume status and cardiac function with bedside ultrasound.

And then, remember that there's a risk—so a lot of the patients, I would say, most of the patients that I see come in from home with a very slow rate, who have symptomatic bradycardia, are on both a calcium channel blocker and a beta blocker that they've been taking prescribed by their outpatient doctor, maybe by 2 different doctors. But it's better to stay away from both agents in your patient.

Once their blood pressure drops, they need emergent cardioversion.

Amanda Balbi: Very interesting.

Jeffrey Tabas: Good, I’m glad it's interesting!

Amanda Balbi: I always like the presentations with case reports attached because that's such a good example of it reinforces the point that you're making.

Jeffrey Tabas: I learn everything from like case reports, like it just sinks in when you think of the case. I'll never forget this patient actually. It might have even happened 20 years ago, maybe 15 years ago. The principles have all held. It's amazing. The same mistakes keep occurring.

Amanda Balbi: Thank you so much for speaking with me today. And for our listeners, stay tuned for the subsequent parts of this series.

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