Atrial Fibrillation with RVR and Diltiazem

[systemet]

Anyone have any idea what this might be about? Anybody ever heard of diltiazem causing stable patients to go unstable?

I think there's a few potential issues.

1. Correlation vs. causation: a stable patient given diltiazem who has no or minimal response is more likely to have their symptoms worsen in 30' than improve. Any change in condition may be attributed erroneously to the effects of the diltiazem.

2. Diltiazem is still a negative inotrope, and while "cardioselective", with a lower incidence of hypotension than verapamil, true pharmacological selectivity is a theoretical ideal more than a practical reality. So some vasodilation will occur to varying degrees in diiferent individuals.

3. Recall bias : everyone remembers (and QIs, and sends the chart to the medical director) of the guy who get diltiazem, sewers his pressure to 60/30, and then codes. No one really remembers the guy whose rate slows and rapidly improves.

4. Inappropriate patient selection: honestly, I think most of the a.fib patients I've seen / heard of getting verapamil, diltiazem, metoprolol, etc probably shouldn't have. If we givve a CCB to somone old and septic wirth a compensatory tachycardia, bad things are going to happen.

5. Unidentified or occult underlying re-entry, e.g. WPW

6. Interaction with the patients own oral AV nodal blocking meds.

[Bieber]

Great response, Systemet! Thanks for pointing those out. You're right, it could very well be one or more of those things that the medical society is thinking about; unfortunately we weren't given much of an idea of what situations/statistics/cases where patients have had a poor outcome following diltiazem therapy. Maybe I'll be able to find out more when we have our new protocol training. Thanks for giving me some ideas, though.

[systemet]

Great response, Systemet! Thanks for pointing those out. You're right, it could very well be one or more of those things that the medical society is thinking about; unfortunately we weren't given much of an idea of what situations/statistics/cases where patients have had a poor outcome following diltiazem therapy. Maybe I'll be able to find out more when we have our new protocol training. Thanks for giving me some ideas, though.

I think that a lot of these medical advisory decisions are often made in a fairly unscientific manner, based on a couple of situations where bad outcomes have occured. The committees have a clear responsibility and duty to protect the patients, but I think they often end up restricting practice based more on a few bad incidents than a thorough and scientific evaluation of the data. Not to mention, a system has to be quite large to be seeing enough of these patients in a year to generate real statistics.

Often the end result is something as useless as "Because paramedic administration of diltiazem in symptomatic atrial fibrillaton hasn't been shown to improve outcomes.....". This is a fairly meaningless statement that means a lot less than the casual read would suggest, and is entirely compatible with "paramedic administration of diltiazem in symptomatic atrial fibrillaton hasn't been shown to worsen outcomes.....", or "we made a fairly random decision based on the loudly expressed opinions of a few particularly vocal individuals, and wanted to dress it up in pseudo-academic language.".

As has been noted before, it's often easier to restrict practice than it is to train individuals up to an acceptable level and run a decent QI program (not to imply that this is an issue with your service).

[mikeymedic1984]

I would just remind everyone that there are people who walk around with some pretty funky rhythms everyday that have not been diagnosed --- everything from >20 PVCs, runs of VTach, sinus pauses greater than 4 seconds, and some rhythms that 3 cardiologists would give you 3 different interpretations on. In my eyes, Chest pain alone is not enough to shock people. You need to look at the overall picture and decide if they are critical or holding their own. I would hope that just because I have chest pain and a funky rhythm that I will not get electrocuted by an overanxious medic. Start an IV, put the pads on, be ready to shock if needed, try meds first, but dont freak out because the rhythm is not what you percieve as normal.

[Just Plain Ruff]

i second that mikey

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