coumadin and afib

[obiwan]

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you don't bridge with UFH or LMWH unlike in DVTs or PE, why is that?

and in the middle of the night cross cover for afib, what is your drug of choice and do you right off the bat anticoagulate with heparin?

 

[IMdocT]

i thought you can bridge, and it's either heparin or lovenox. but it's not as important if there's no clot, whereas in DVT you already know you have a clot. maybe i'm wrong?

 

[staup]

i thought you can bridge, and it's either heparin or lovenox. but it's not as important if there's no clot, whereas in DVT you already know you have a clot. maybe i'm wrong?

You can bridge if you want, but many people don't bridge in afib because most of the data quoting the possibility of stroke are given in a per year format, i.e 2% per year, or 19% per year. So for a couple of days (the time it takes coumadin to become therapeutic), the risk of stroke is miniscule, and many people feel it is not necessary to anticoagulate.

A clot is different, you want to immediately prevent the clot from enlarging, so bridge. There is also a theory about warfarin creating a hypercoagulable state when first initiated (before becoming therapeutic), so you would also want to avoid that when a person already has a clot, and you avoid it by anticoagulating them with heparin until the INR is therapeutic > 24hrs.

In the middle of the night, the most common drugs to use are metoprolol or diltiazem (with dilt being more effective in my experience). Many people use amio when those drugs do not work or hypotension is an issue. Many types of BBs and CBBs are used, and then there are other exotic antiarythmics if needed.

Finally, most people do anticoagulate immediately with new onset afib possibly because the initial conversion is time ripe for clot formation or because PE is a likely cause of new afib. Immediate anticoagulation is debatable though.

 

[dragonfly99]

verapamil is a better AV node blocker than diltiazem or metoprolol.
If the patient has low blood pressure chronically, then digoxin may be necessary (i.e. if you feel you can't use beta blocker or calcium channel blocker). Amiodarone can cause hypotension if you are doing amio IV loading, usually due to running in the infusion too quickly (i.e. less experienced nurse) - the treatment for that is to stop or slow down the infusion.

Agree w/above r.e. the heparin or Lovenox bridging. If the person has a pretty high CHADS score, you should at least consider bridging with Lovenox, particulary if the patient is able to give the shots at home and has insurance (Lovenox is expensive...).

 

[staup]

verapamil is a better AV node blocker than diltiazem or metoprolol.
If the patient has low blood pressure chronically, then digoxin may be necessary (i.e. if you feel you can't use beta blocker or calcium channel blocker). Amiodarone can cause hypotension if you are doing amio IV loading, usually due to running in the infusion too quickly (i.e. less experienced nurse) - the treatment for that is to stop or slow down the infusion.

Agree w/above r.e. the heparin or Lovenox bridging. If the person has a pretty high CHADS score, you should at least consider bridging with Lovenox, particulary if the patient is able to give the shots at home and has insurance (Lovenox is expensive...).

Verapamil is a good choice as well.

The one point I would make about Dig is that is doesn't work well with sympathetic discharge. So, when a person is at rest, it can work well, but when a person is walking, it is less effective.

Agree with everything else though.

 

[jdh71]

People get put on drips way to often for afib. I think it's important to note that not everyone needs a ****ing dilt drip for asymptomatic rates in the 130s. For simple RVR I personally like IV metoprolol boluses, which can be converted over to oral for most cases. It's a matter of style.

My experience with bridging for afib, especially new onset, appears to be very attending specific. The cards guys at my program tend to be more nervous about it, then the hospitalists who tend to dispo without the bridge.

 

[LukeWhite]

A lot of the motivation of bridging in Afib of unknown duration is to minimize coumadin-induced necrosis due to the short-term hypercoaguability. The risk of stroke paradoxically increases (at least theoretically) in the short term due to coumadin's broad effect on anticoagulant as well as procoagulant factors. A few days of lovenox minimizes this.

 

[LukeWhite]

A generic enoxaparin is imminent (possibly already in pharmacies?) which should in any case make the debate less pressing.