In second-degree AV block type I, the PR interval _____. a. ...

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In second-degree AV block type I, the PR interval _____.
 
  a. shortens
  b. is absent
  c. is inconstant
  d. remains constant

Question 2

A line between waveforms is called a(n) _____.
 
  Fill in the blanks with correct word

[fwbard]

Answer to Question 1

C
In second-degree AV block type I, the PR interval is inconstant and the PR interval after a nonconducted P wave is shorter than the interval preceding the nonconducted beat.
Although progressive lengthening is a phrase that was used for many years to describe the behavior of the PR intervals associated with second-degree AV block type I, use of this terminology is no longer recommended; rather, the term inconstant or generally progressive PR intervals is recommended. Use of the term inconstant or generally progressive PR intervals is important because many type I AV blocks are atypical, missing one or more of the features of the classic Wenckebach phenomenon. For example, the second conducted PR interval after a blocked impulse may fail to show the greatest increase in length; instead, the PR interval may actually shorten and then lengthen in the middle of a grouped beating pattern. Alternately, the duration of the PR intervals may show no obvious change in the middle or for a few beats just before the end of a group.

Answer to Question 2

segment

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Gracias!

[FergA]

TYSM