Mobitz 2

[Dentaybow]

My 70 year old sister, who is in otherwise good health and very pphysically active began experiencing intolerance to even light activities about two months ago.  Her primary physician referred to her a cardiologist after  she 'flunked' a treadmill test.  In the few minutes she was on the treadmill, her heart rate dropped dramatically and she was unable to continue.  She was referred  to a cardiologist.  The cardiologist said she had a Mobitz 2  heart block and would have to have a pacemaker.

Her tolerance to activity continues to decrease.   Example:  making the bed in the morning induces weakness, light-headedness, etc and she will lay down  for a while to regain the ability to continue. She also has minor 'self-diagnosed' symptoms of GRD.

Questions:
How long can the placement of a Pacemaker be reasonably delayed?  Weeks? Months?

Would it be best to do further tests  to determine the underlying cause  of this arryhthmia before proceeding with the pacemaker?  Namely,  rule out  ischemic heart disease/ CAD by doing such things as a Persantine Test and/or an angiogram?

If the underlying cause of the Mobitz ll was CAD and that was treated,  would it negate the need for a pacemaker?

Thank you for your advice and opinons.

[Michael J. McWilliams, M.D.]

Symptomatic slow heart rates are clear indication for a pacemaker.  I usually do not delay in putting pacemakers in for cases like this. If she falls and breaks a hip, the recovery can be long and there are significant risks.  There is no direct answer to your first question.  I would advise my patients not to wait in cases like that.

I would put in the pacemaker first.  Blockages in the artery are an unlikely cause of exercise induced bradycardia.  Further coronary work up might be helpful, but I would not delay based on that.

It would be very unlikely that Mobitz II is caused by ischemia.  If she really has Mobitz II (rare),  I would put in a pacemaker.  If she has Mobitz I (much more common), I would still put in a  pacemaker for exercise related symptomatic slow heart rates.  Like I said, I do not disagree with the coronary disease work up, but I do not think it would delay my recommendation for a pacemaker. I worry about falls and fractures the related comorbidities -- this could be very dangerous.


I hope this helps.  Thanks for posting.

[Dentaybow]

Thank you for your prompt response.

Besides the worry about falls and fractures, is there reason to be concerned that the Mobitz 2 could progress to CHB or asystole?

Thank you again.

[Michael J. McWilliams, M.D.]

yes, Mobitz II has a relatively high rate of progression to complete heart block.