arrhythmia during cpap titration

[michaelrack]

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I was reading a cpap study earlier today on a male in his mid-30's with mild osa. The EKg leads during his diagnostic sleep study were normal. During the CPAP titration study, there were frequent nonconducted p waves- appearing to be type 2 2nd degree AV block. No significant past med hx.

Any ideas other than getting him to a cardiologist right away?

thanks

 

[dragonfly99]

I agree w/cards consult. However, if a patient only has heart block and/or pauses during periods of hypoxia or hypercarbia, the treatment is CPAP and/or oxygen, not a pacemaker...

 

[yappy]

Perhaps the ventricles were becoming irritable due to low oxygen levels and threw some PVC's. Is their a chance that you have mis-interpreted some regularly-spaced-PVC's as a second degree heart block?




Nocturnal ventricular arrhythmia in patients with sleep apnea and suspected coronary heart disease

Koehler U, Glaremin T, Cassel W, Feuring M, Pomykaj T, Schäfer H, Stellwaag M.

CONCLUSION:
Patients with coronary heart disease, obstructive sleep apnea and severe hyoxemia are at higher risk of developing nocturnal PVC because reduced hypoxic tolerance of the heart may lead to electrical instability.

Keep us updated.

 

[J-Rad]

No one is going to confuse PVCs with Mobitz 2 HB or non-conducted PACs (another possibly cause of P waves without a following QRS).

 

[yappy]

Oh. Well then I'm stumped. I could not find any studies on mobitz type II caused by a sleep study....

GL.

No one is going to confuse PVCs with Mobitz 2 HB or non-conducted PACs (another possibly cause of P waves without a following QRS).

 

[michaelrack]

I commonly see arrhythmias (usually PVC's) on diagnostic sleep studies that improve, or at least don't get any worse, during the CPAP study.

About once a year (over 2000 sleep studies) I will see a patient whose EKG leads are stone-cold normal during the diagnostic study develop some type of arrhthmia with CPAP- at pressures that are controlling the sleep apnea. 2 possible explanations I can think of for this phenomenon are 1) night-to-night variabiltiy and 2) interval development of a cardiac problem (the 2 sleep studies may be separated by several weeks.

I am puzzled by this case of AV block. Apparently the pcp did telemetry which showed only several episodes of the block; the patient is using CPAP. I am leaving his arrhythmia management up to the pcp. I will give you an update when I see the pt for the first time in clinic in several weeks.

thanks

Michael Rack

 

[J-Rad]

Just making sure: it was Mobitz II and not Mobitz I (Wenckebach)? I am not doubting your EKG reading ability, but occasionally I've read a Holter in which the PRI prolongation seemed a little more subtle. I ask because, at least in my world (peds cards), Wenckebach that only occurs during sleep can be a benign phenomenon.

 

[michaelrack]

Just making sure: it was Mobitz II and not Mobitz I (Wenckebach)? I am not doubting your EKG reading ability, but occasionally I've read a Holter in which the PRI prolongation seemed a little more subtle. I ask because, at least in my world (peds cards), Wenckebach that only occurs during sleep can be a benign phenomenon.

It looked like Mobitz II to me. But I won't be able to provide any definite info to SDN for at least several weeks.

 

[dragonfly99]

Agree that it's easier than one would think to sometimes confuse Type I w/Type II mobitz, and that Type I during sleep is something I've seen in adult cards also. Also, this could have been blocked PAC's rather than Mobitz II. It might have been unrelated to the CPAP titration, too...these things come and go in patients who have them.

 

[J-Rad]

I love blocked PACs; very glad when I can ascribe a long-ish pause to them. This was not the case for a patient of mine, substantially younger than teenaged, and who has significant CHD of the variety that only gets palliated who had up to three second pauses on a Holter and HRs to the low thirties, not always while asleep. Reported to get down to the high twenties on the night before getting the pacemaker. This, of course, has nothing to do with the above, just my fun abnormal heart rhythm story to share🙂

 

[michaelrack]

Agree that it's easier than one would think to sometimes confuse Type I w/Type II mobitz, and that Type I during sleep is something I've seen in adult cards also. Also, this could have been blocked PAC's rather than Mobitz II. It might have been unrelated to the CPAP titration, too...these things come and go in patients who have them.

Blocked PAC's are a possibilty. I will see if I can post the abnormal EKG strips this week.

 

[michaelrack]

http://rebeldoctor.blogspot.com/2012/05/eng-during-sleep-study.html

here it is (my IT chief accidentally put it on my old rebel doctor blog rather than my sleepdoctor blog)

 

[J-Rad]

A little tough on the screen and at such a compressed rate, but I think I agree that it looks like Mobitz 2.

 

[michaelrack]

thanks