Transcript Heart Block

EKG Analysis
Heart Block
Heart Block: Slow Conduction of
Depolarization Impulse
Usually occurs at the A-V node. May be
due to disease, ischemic damage, or drug
toxicity.
First Degree Heart Block

Everything looks sinus EXCEPT the PR interval is
greater than .20 seconds
First Degree Block
First Degree Block
Second Degree Block Mobitz I
Wenckebach
PR interval gets longer on each successive beat until
one does not conduct (no QRS)
 The cycle then repeats
 R-R irregularity

Second Degree Mobitz I
(Wenckebach)
Second Degree Mobitz I
(Wenckebach)
Second Degree Mobitz II

Not every P wave conducts (no QRS)
Usually a fixed ratio of P waves to QRS complexes



The P waves that do conduct will have a consistent PR interval
R-R irregularity
May require a pacemaker if it happens after an M.I.
Second Degree Mobitz II
Second Degree Mobitz II
Third Degree Block (Complete)



No P waves are conducted
Ventricles depolarize on their own so QRS duration is >.12
No relationship between P waves and QRS complexes
R-R will be consistent however
No PR interval is present (don’t be fooled!)


P waves are going at their own rate while the ventricles go at
their own rate
Patient will need a pacemaker
Third Degree Block (Complete)
Laboratory Exercises # 5
Numbers 9-12
Laboratory Exercises #6
Numbers 1-8