A patient had AVR/MVR/RFA and post surgery his native rate/rhythm was aflutter 40's to 50's with BBB. He was asymptomatic with this rate/rhythm and perfusing well (maps 70s to 80s) & mentating fine. Post op day 1 (post extubation) he was not paced. Post op day 2, they decided to AV pace him.

The surgeon ordered 12.5 mg po metoprolol for this patient. He was AV paced, pressure was fine, but his underlying remained the same. The order was triple checked with the charge RN, the resident, and the surgeon--all said ok to give--so it was given. Later in the shift, his underlying rhythm was checked--asystole! Not sure if it was the metoprolol or if his heart was stunned from the epicardial pacer and just slow to pick up native beat?

Just curious about what you would have done with the metoprolol given this situation. Thanks.

Phew, that sounds really suspicious to me...I would have given it with A LOT of trepidation.

Perhaps it was meant to suppress any tachyarhythmias, but you would think that the overdrive pacing of the pacer itself would take care of that if it had occurred.

I can't wait to hear more responses on this one...

Yes, would some smart people care to drop some wisdom? Very interesting

Like dawn said, beta blockers are really kind of an odd choice. Especially if it's new onset a-flutter like that. Good thing he was paced:lol2:

What a cool case, he was post open heart right?

I would love to see the original rhythm strip and a 12-lead to see if he really was in aflutter vs a heart block with an escape rhythm. Do you remember what his atrial rate was, you said the ventriculae rate was 40-50? I wonder if they were afraid he would go into a tachy arrhythmia from the pacer or convert from flutter to fib? So they gave lopressor just incase.

-Do you remember were there P-waves when you turned off the pacer? Also, what was his K+ level.

-Smiley

Beta blockers, especially at lower doses, are often used to help convert Afib/flutter to sinus rhythm.

Beta blockers, especially at lower doses, are often used to help convert Afib/flutter to sinus rhythm.

Yes, that makes sense, I suppose it was worth the risk because they had the pacer in case it backfired (which it did) but it is always better to have the heart beating on its own in a SR with a back-up pacer in place, then to have a pacer having to initiate most, if not all, the beats.

Thanks, that does seem like the rationalization...

;)

the beneficial effect of beta-blockers in preventing postoperative atrial fibrillation (af) is well known.

excess catecholamines in the postoperative patients may be one reason why pacing is not effective in suppressing af. by blocking catecholamines, beta-blockers enhance the ability of pacemakers to prevent the initiation of af and minimize the likelihood of pacemaker-induced af.

We always have a beta blocker ordered on our Post CABG pt. Usually to start the next am. We also always have epicardial pacer wires and test wether it fires on admission post op recovery. If the true underlying is Aflutter....I would have given it as long as my pacer fired and my pt had a BP. I would have also liked to see the original strip or original 12 lead. I would not have given cardizem or verapamil (although a different class of drugs). We do not treat afib until it becomes a rapid rate >130 or the patient is symptomatic. We do not try to "pace out" of afib. With a pacer and a bp I would have given it.....usually...there are always exceptions specific to you r patient....

It's amazing the way we all practice differently according to our docs. One of the questions on the CSC certification review test, I took to my CT surgeon and he said that he WOULD NEVER DO THAT (calcium channel blocker) soooo...it's in how we practice too.

Remember, asystole is what you get when you combine a right bundle branch block with a left bundle branch block. With RFAs you are trying to interfere with an abnormal conduction pathway. With valve surgeries, it is common to "accidentally" interfere with conduction pathways (normal or abnormal) due to the very location of the valves. The simple act of suturing and the inflammatory process can do this, which is the reason why surgeons place temporary epicardial pacer wires. Since this guy was halfway there (with a R or L BBB) perhaps this inflammation advanced his existing block into asystole. Since the patient was most likely on a Bblocker pre-op and still in an atrial rhythm, I think it would be appropriate to restart it post-op, especially since he had AV wires (At least more preferable to cutting it cold turkey.) I'd rather be 100% AV paced than have flutter any time.

A patient had AVR/MVR/RFA and post surgery his native rate/rhythm was aflutter 40's to 50's with BBB. He was asymptomatic with this rate/rhythm and perfusing well (maps 70s to 80s) & mentating fine. Post op day 1 (post extubation) he was not paced. Post op day 2, they decided to AV pace him.

The surgeon ordered 12.5 mg po metoprolol for this patient. He was AV paced, pressure was fine, but his underlying remained the same. The order was triple checked with the charge RN, the resident, and the surgeon--all said ok to give--so it was given. Later in the shift, his underlying rhythm was checked--asystole! Not sure if it was the metoprolol or if his heart was stunned from the epicardial pacer and just slow to pick up native beat?

Just curious about what you would have done with the metoprolol given this situation. Thanks.

I am in no way the ultimate expert on these things but as an NP in a CVICU setting, I have an understanding of these things (or at least, I should). Anyways, was it really a Radio-frequency Ablation (RFA) that was performed or a Maze procedure? Typically when a patient presents with valve insufficiencies or stenoses in addition to a pre-existing atrial fibrillation, the surgeon performs a MAZE procedure during the actual open heart surgery and this is not the same as an RFA. The Maze or Cox-Maze (after Dr. Cox who developed it) involves a series of precise incisions made in the right and left atria to interrupt the conduction of abnormal impulses allowing for sinus impulse to travel to the AV node as they normally should. The success rate is 98% in lone a.fib. and 90% overall. I bet you this is what was done on this patient as cardiac surgeons perform the Maze whereas cardiac EP docs perform the RFA.

Most patients who present to the ICU after open heart surgery and a Maze procedure have all sorts of funky rhythms initially. I've seen the whole gamut of asystole, junctional rhythms, and a.fib. even after a Maze but these usually recover after most of the swelling from surgery subsides. I am also interested to figure out what the inital EKG for this patient was. If it was truly A flutter, then I believe it would be difficult to pace the atria but you said you were able to A-V pace the next day.

At my facility, we usually pace patients with HR less than 60 post-operatively even if the MAP is OK. For the most part, many patients are in a junctional rhythm after the Maze so AAI pacing helps with that atrial kick, thus improving the cardiac index (not only the MAP). We also do not start Metoprolol on post-op day 1 if the patient is pacemaker-dependent. We start an ACEI instead if the kidneys can handle it. If we can't start an ACEI, we sometimes use Hydralazine for afterload reduction and to take advantage of its tachycardia side-effect. The Beta Blocker does get started after the rate has recovered and the patient is off the epicardial pacing.