1. 2nd Degree AV heart block Mobitz I
A 2nd degree heart block Type I or Mobitz I, is commonly
referred to a "wienkebach". Remember in the story of
"Penny and Quinton" when Quinton suddenly did not come
home, then he would come back, try to get close, but then
drift further, further away, until he did not come home
again. Since "Penny", the p-wave, is initiated in the SA
node, in a 2nd degree block, the SA node is trying to pace
the heart in a normal fashion, but a "block" or slowing is
along the line that is causing the impulse to fail to make it to
the bundle branches. So, the p-wave is ever present, but the
QRS does not show up sometimes. The major difference on
a strip to identify this rhythm is if the PR interval "walks
out". It does not have to be in a set of three like the
song, "long, longer, longest drop, now you have a
weinkebach", it just has a pattern of normal PR
intervals, then there is some distancing and then dropped
The electrical pulse of the
QRS complex, and then the SA node tries again by having a normal heartbeat begins in The current then runs
normal PR interval. As you can imagine, this heart rate will The SA node. along tracts to the AV
be slightly irregular, but a p-wave is present every time that node.
a QRS is present.
What do you do?
If this is a new onset and the doctor is unaware, and
especially if the rate is bradycardia, you should call the
doctor. But make sure you have a 12-lead EKG and you have
monitored the patient closely before calling. Sometimes a
patient may go in and out of this rhythm. If this is the
case, and the patient is unsymptomatic, monitor the patient
closely and report on rounds.