Intermittent Atrial Fib

[1EMT-P]

During the first five minutes of transport she reports right sided jaw pain x 2 days. Her temp is 37.1

[rock_shoes]

During the first five minutes of transport she reports right sided jaw pain x 2 days. Her temp is 37.1

Ah, so it likely is compensatory. Scratch the CCB for the time being then. What's her dental history? Any recent trips to the dentist? Take a look in the mouth. Any sign of an abscess? It's amazing the s&s that rear their head with dental/jaw infection.

[1EMT-P]

Upon arrival at the ED it was discovered that she did indeed have an upper respiratory infection. Her labs and x-rays revealed and infection in addition to a magesium level of 1.3. She was given 2gm Magnesium IV, 1 Duo Neb Treatment, Solumderol 125mg IV & 1GM Rocephin IV. She was admitted for 23 hour observation.

[Levi]

Agreed on the Ventolin/Atrovent.

Anyone else thinking we should consider a beta blocker or a CCB with a 30 minute transport time? Worth giving the Doc a ring and having the discussion anyway. She's already paced so it's lower risk than most patients (a demand pacer considering the ECG findings being shared) and based on her history we're probably looking at an a-fib less than 48 hours old. I'm surprised her medications don't include coumadin or dabigatran. I'm leaning more toward a CCB over a beta blocker in this case with signs of bronchospasm also presenting (I know in Alberta it's metoprolol or metoprolol but a guy can dream).

Not all patients are on anticoagulation for atrial fibrillation, but she probably should be with her medical history. This would not be an afib < 48 hours old though, as she has a documented history of afib. I would consider rate control if you thought her symptoms were related to her atrial fibrillation, but they're more likely due to her respiratory issues.

[1EMT-P]

They opted not to give her anything for rate control since she was already on a beta blocker. Instead they opted to treat her upper respiratory infection & also her low magnesium level. I checked on her the next morning. Her A-Fib had resolved. They increased her beta blocker, added magnesium oxide.

[rock_shoes]

Not all patients are on anticoagulation for atrial fibrillation, but she probably should be with her medical history. This would not be an afib < 48 hours old though, as she has a documented history of afib. I would consider rate control if you thought her symptoms were related to her atrial fibrillation, but they're more likely due to her respiratory issues.

Documented history yes. Constant a-fib not necessarily. Some patients go in and out of a-fib based on any number of things. With this patient it was likely related to both low magnesium levels and a respiratory infection. I did qualify the consideration of CCBs with ensuring the rate was not in fact compensatory (respiratory infection in this case).

They opted not to give her anything for rate control since she was already on a beta blocker. Instead they opted to treat her upper respiratory infection & also her low magnesium level. I checked on her the next morning. Her A-Fib had resolved. They increased her beta blocker, added magnesium oxide.

All sounds perfectly reasonable to me. Interesting case. Any idea why her magnesium levels were in the toilet?

[Levi]

Documented history yes. Constant a-fib not necessarily. Some patients go in and out of a-fib based on any number of things. With this patient it was likely related to both low magnesium levels and a respiratory infection. I did qualify the consideration of CCBs with ensuring the rate was not in fact compensatory (respiratory infection in this case).

All sounds perfectly reasonable to me. Interesting case. Any idea why her magnesium levels were in the toilet?

The reason we worry about afib with a duration of >48 hours, as I'm sure you know, is the risk of post-cardioversion stroke from embolizing a clot out of the left atrium. If somebody has a history of atrial fibrillation their stroke risk is the same regardless of whether they have intermittent or permanent atrial fib. So in someone with intermittent afib, the concept of <48 hours vs >48 hours does not apply to them.

If you have a patient with known afib you should NOT cardiovert them chemically or electrically, unless they have been on anticoagulants for at least 4 weeks. Of course this doesn't apply to a patient who is hemodynamically unstable.

Edited December 21, 2013 by Levi

[rock_shoes]

The reason we worry about afib with a duration of >48 hours, as I'm sure you know, is the risk of post-cardioversion stroke from embolizing a clot out of the left atrium. If somebody has a history of atrial fibrillation their stroke risk is the same regardless of whether they have intermittent or permanent atrial fib. So in someone with intermittent afib, the concept of <48 hours vs >48 hours does not apply to them.

If you have a patient with known afib you should NOT cardiovert them chemically or electrically, unless they have been on anticoagulants for at least 4 weeks. Of course this doesn't apply to a patient who is hemodynamically unstable.

Great information. I'm with you in finding it rather odd this patient was not anticoagulated. Are these criteria not modified based on frequency? For example a particular patient goes into a-fib 1-2 times a year and is succesfully cardioverted each episode within 24 hours. Is that patient really considered the same risk level as an intermitent a-fib patient who is in and out of it every other day?

Both of these patients should likely be anticoagulated, but based on exposure it would seem the higher frequency a-fib episode patient would be at higher stroke risk than the lower frequency a-fib episode patient.

In my own experience these patient's know their INR, and they know how stable their INR is within the accepted range. They might not know why their INR is significant, but all of them seem to notice how interested every doctor they see is in it.

[Levi]

Great information. I'm with you in finding it rather odd this patient was not anticoagulated. Are these criteria not modified based on frequency? For example a particular patient goes into a-fib 1-2 times a year and is succesfully cardioverted each episode within 24 hours. Is that patient really considered the same risk level as an intermitent a-fib patient who is in and out of it every other day?

Both of these patients should likely be anticoagulated, but based on exposure it would seem the higher frequency a-fib episode patient would be at higher stroke risk than the lower frequency a-fib episode patient.

In my own experience these patient's know their INR, and they know how stable their INR is within the accepted range. They might not know why their INR is significant, but all of them seem to notice how interested every doctor they see is in it.

You're probably right that a patient who goes into afib 1-2x/year and is out of it quickly is not at the same risk. In reality though, that type of patient is probably very rare and there's no safe way of identifying those patients. The usual course for afib is that they're in and out of it quite often, and the vast majority of people can't reliably tell you when they're in it. If you've seen 99% of the patients I have, they will be in afib and have absolutely no symptoms of palpitations or other awareness. So the safest option is to assume all patients are the garden variety 'intermittent afib' who have been shown in studies to have the same stroke risk as someone who is permanently in it.

As an example in this same patient we're been talking about, they were probably symptomatic from their respiratory infection, so it's hard to really say how long they've been in afib. There's a good chance the resp infection may have precipitated the episode, but they may have been in and out of it for the past several months and have a big clot that has formed. Another option with these patients if you feel you need to cardiovert now is to do a transesophageal echocardiogram, and take a look at the atrium and a special area called the left atrial appendage where the clots like to form+hide. If there's none there you're pretty safe to go ahead and cardiovert.

To answer your other Q: the choice to anticoagulate is not based on how often they go into afib (because of the studies showing no difference in stroke risk), but rather on their overall stroke risk. There's a risk calculation tool called CHADS2 that stands for CHF, hypertension, age (>75), diabetes, and prior stroke. Stroke gets 2 points, and all the rest get 1 point. If you have 0 points a daily aspirin is probably okay, if you have 1 point you can go with either ASA or warfarin depending on judgment, and 2+ points they should be on warfarin.

[1EMT-P]

In the back of my mind I was asking should we give this lady 5mg of Metoprolol IV to slow her rate & I was wondering why she wasn't on coumadin or some other agent. The other thing that I thought was odd was that she was not given Heparin or Lovenox.