Wenkebach

Took care of a pt. today with a new inferior AMI. Has a history of Wenkebach, old CABG and stent placement.

Was on Cozaar preadmit.

Strips show the usual elevation in II, III, and AVF; a very stable Wenkebach. Trops went the usual way, nothing abnormal. k+ 3.6, would have liked to supplement, but no orders after reporting. Pt. had a great day.

Besides the usual post-perfusion (Retavase) ectopy, no arrythmias.

Stable rythm, Wenkebach. On Heparin, Lido, and Aggrastat.

Anything else besides the usual I should look for in a pt. with Wenkebach?

I admit, haven't seen one in along time.

Cate

Of all the AV blocks, Wenkebach is probably the most benign...(less likey to degenerate into complete AV disociation(sp?)/3rd degree AVB). As with any block, however, keep an eye on rate and blood pressure. Patients never(VERY RARELY) become unstable from wenkebach alone. IF your patient does it most likely is unrelated to the rhythm.

As far as causes, it's usually drug related. (ie: dig level? , does pt take beta blockers?, etc, etc.). Certainly can be from coronary disease or cardiomyopathy, or electrolyte disturbances, but many times from meds.

I would just watch for the av block to deteriorate further to mobitz II or 3rd degree. As you know, inferior MI complications are blocks and bradys. Kind of surprised they allowed a fresh MI to sit on a K+ of 3.6 though.

Pt. did earn a temporary pacer(a little late in my opinion), as well as a trip to surgery for an implanted pacer.

When Mobitz I degenerates into Mobitz II, isn't immediate perm. pacer therapy indicated?

I know the answer, I just need clinical opinion as a backup.

Thanks

When Mobitz I degenerates into Mobitz II, isn't immediate perm. pacer therapy indicated?

Nope. It all depends on what is causing the rhythm. As an example, what if the rhythm is due to hyperkalemia (av-blocks are a common complication of high potassium)? Or perhaps drug effect (too much beta-blocker?, etc.)?

Even with cardiac ischemia, if you can successfuly(sp?) reverse it (pci, etc.) you can fix the rhythm.

Fixing the underlying problem will (usually) fix the AV-block.

And....if they're hemodynamically stable, you may even safely hold off using a temporary pacemaker (many/most people hold a bp with mobitz-2). I've taken care of (and im sure others here have) people in complete AV-dissociation/3rd degree, who held a pressure with it...presenting with 'a little dizziness on exertion'.

So...no you dont go rushing into permanent pacers without a work-up/ resolution of the cause of the rhythm.

The people who go into av-blocks requiring permanent pacemakers usually have an underlying chronic cardiovascular disease (cardiomyopathy, etc.) or are unlucky enough to infarct in just the right spot.

All of our cardiologist and surgeons have standing orders for ss potassium replacement.

Pt. did earn a temporary pacer(a little late in my opinion), as well as a trip to surgery for an implanted pacer.

When Mobitz I degenerates into Mobitz II, isn't immediate perm. pacer therapy indicated?

I know the answer, I just need clinical opinion as a backup.

Thanks

The major issue here is that if the patient has an MI, they potentially are having the block because of the MI. Inferior MI's can do some crazy things to rhythms also. I've seen patients have Mobitz II from Inferior MI's and once reperfusion was established, they return to SR w/o any ectopy at all.

If Mobitz I deteriorates to Mobitz II, a temporary pacer may be indicated, but not a permanent w/o determining the underlying cause. As Dinith said, the cause can be a variety of things, and many are "fixable" without requiring the implantation of a Permanent Pacer. I've seen many patients who were over medicated, w/ Beta-Blockers, Dig. or Ca++ Channel Blockers. Esp. renal pt.'s that some "smart" doc started on .25mg of Dig. QD.

Doug

Thank you all for the replies! You are all so helpful!

This pt. evolved into a Mobitz II due to the new inferior MI, drug toxicity was r/o. He was'nt on anything that would seemingly be causal. Hypokalemia was eventually corrected (I agree, too late, the cardio had a brain fart or something...) the perm pacer was due to the fact that beyond reperfusion, the arrythmia persisted for 4 days. (Too little time for it to resolve, perhaps?)

Anything else for me to evaluate?

Once again, thanks so much!