Atrial fibrillation April 2nd, Thursday

On Thursday we talked about atrial fibrillation, this is a hard topic to cover in 30 minutes because there are so many levels. We first talked about an approach to tachycardia

1. Stable vs unstable (BP <90, chest pain, level of consciousness)

2. Wide or narrow

3. irregular or regular

P waves can be difficult to see even in sinus tachycardia, so looking at the RR intervals (are they the same) can be helpful when you are called to assess this patient.

So once you've diagnosed afib, things to consider

1. Stability - do they need a shock now? 

2. How long have they been in afib? If less than <48 hrs, we can consider shocking them to put them in sinus rhythm, if >48 hours we are worried that by converting them to sinus rhythm they a clot. KEEP IN MIND, this risk is present with chemical cardioversion - amiodarone, sotalol, flecainide, propafenone. If we don't know when they've been in afib, we can also do a TEE to rule out a thrombus before shocking.

Question you may have: I don't get it, how can we NOT know, wont' they tell us when their SYMPTOMS started? 

This is what makes this quite tricky, some patients have no symptoms even with HR >130, others can be in afib, HR 80 but feel palpitations associated with the irregular heart rate.

3. Rate vs Rhythm control: As per the affirm trial, we now believe rate is just as good for rhythm control in terms of risk of ischemic strokes, rhythm control has more side effects.. BOTH individuals are generally anticoagulated (refer to CCS updated guidelines 2014 http://www.onlinecjc.ca/article/S0828-282X%2814%2901249-5/abstract). 

So who gets rhythme control? Individuals that feel symptomatic when in afib, regardless of rate, we consider medications and if that fails, we an do a procedure known as pulmonary vein ablation.

4. If we opt for a rate control, what rate is ideal? As per the RACE II trial, <110 as a goal was equivalent to a strict rate of 80. The study was only 2 years and so we don't actually know if patients can have heart issues if they are consistently have a heart rate of 110. Guidelines recommend <110 is ok if symptoms are controlled, cardiologists I've discussed with usually aim around ~80 but a patients age/context would be taken into account.

5. Workup, I forget to mention this, but EVERYONE will get a TSH. We should also check electrolytes, consider PE as a cause. An echo will help look for MR, or other valve disease that would advise us to NOT use any NOACs. What is valvular disease? Generally Mitral regurg, mitral stenosis, aortic stenosis, aortic regurg. These patients have often been excluded from many of the afib trials.

6. Anticoagulation: with the newest guidelines, CHADS 1 or greater with patients older than 65 are recommended to be on anticoagulation, this largely based on the new oral anticoagulants (credit Dr. Dresser). An interesting study to be aware of, the AVERROES trial comparing aspirin to apixaban in patients who could not be on afib. This showed a reduced risk of stroke by 50% with no increased risk of bleeding, WOW! 

*note, falls by themselves are not a risk of intracranial bleeds on anticoagulation.

I think that's it for now, until I think of more things to mention.