Indications for chemical cardioversion of Afib

[Doc Ivy]

hey all,

I just admitted a patient from clinic who is a 70 yr guy, very healthy, just some well controlled HTN. No hx of DM, structural cardiac disease, no chronic lung disease, no thyroid disease. Presented 6 months ago with DOE, and palpitations. Found to have paroxysmal AFib/Aflutter. Started on Toprol and Coumadin, and is rate controlled (60-70s) with therapeutic INR. Now having no sxs but feels sluggish on the BBlocker. his cardiologist wants to cardiovert him with Sotalol.

My ward attending and I can't figure out what the strict indication for this is. I'm going to read the AFFIRM trial, but I thought maybe some of you budding cardiologists could enlighten me

Thanks

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[remedios]

hey all,

No hx... structural cardiac disease, no chronic lung disease...

Given no structural heart or lung disease, his odds of staying in sinus is decent. Like one of my attending says, "everyone deserves one shot at rhythm control".

AFFIRM trial results tend to get overgeneralized (especially at Northwestern; it might be a fun exercise to discuss this with Eugene, one of your medicine chiefs). After you read the original paper, also take a look at this editorial:

http://content.nejm.org/cgi/content/full/347/23/1883

I think what it boils down to is that there is a class of patients in whom rate control is definitely more appropriate than rhythm control (e.g., someone with a large left atrium), and a class of patient in which rhythm control is more appropriate (e.g., someone with o/w normal heart and who is very, very symptomatic when he enters a-fib). Then there are the patients in between, which i think this is a case of, where it becomes more of a style thing. And of course, keep in the back of your mind always that real world patients are never exactly the same as the aggregate of study patients.

 

[mellow yellow]

Cardioversion is different than rate v. rhythm control. Don't confuse the terminology. With respect to cardioversion, there are two ways to cardiovert a patient who's in Afib: electrical v. chemical. Dofetilide and ibutilide are two commonly used antiarrhythmics for the purpose of chemical cardioversion. The efficacy of these agents is not great for AFib cardioversion and use of these agents requires continuous tele monitoring due to the high risk of developing ventricular arrhythmias since these agents prolong the QT interval. In general, the success rate of cardioversion for AFib whether chemical or electrical depends on 2 important factors: the presence/absence of structural heart disease and the chronicity of Afib. For patients with structural heart disease who have been in AFib for quite some time, cardioversion is less likely to be successful. In general, electrical cardioversion is more efficacious than chemical cardioversion and most cardiologists will simply perform intraoperative TEE then electrical cardioversion since it's much simpler than doing it by pharmacologic means on the floor where you put the patient at high risk of developing arrhythmias.

 

[Doc Ivy]

Thanks so much for the explanation. Those were some of my thoughts too. I figured that the patient had a reasonable chance of converting and staying in sinus given that this was probably "lone" afib, so cardioversion was worth a try.

 

[applemas]

I have a question here.

How to treat chronic atrial fibrillation? Is there any chance to convert it to sinus rhythm? Are anti-coagulants best method to prevent thromboemolism scene?


Thanks