EKG AnalysisEKG Analysis

Heart Block

Heart Block: Slow Conduction of Depolarization Impulse

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 BlockFirst Degree Heart Block

Everything looks sinus EXCEPT the PR interval is greater than .20 seconds

First Degree BlockFirst Degree Block

First Degree BlockFirst Degree Block

Second Degree Block Mobitz I

Wenckebach

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 I (Wenckebach)

Second Degree Mobitz I (Wenckebach)

Second Degree Mobitz II 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 IISecond Degree Mobitz II

Second Degree Mobitz IISecond Degree Mobitz II

Third Degree Block (Complete)

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 howeverNo 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)

Third Degree Block (Complete)

Laboratory Exercises # 5Numbers 9-12Laboratory Exercises # 5Numbers 9-12

Laboratory Exercises #6

Numbers 1-8