Heart Blocks Flashcards
What does a first degree heart block indicate?
Obstruction at the AV node is not complete. There’s a delay before being transmitted to the ventricles.
What is a second degree heart block?
The block is intermittent. Some impulses will be conducted to the ventricles but not others
What is a third degree heart block?
The block is complete and no impulses will be conducted to the ventricles
What is another name for third degree heart block?
Compete heart block
What are the four types of heart blocks?
First degree
Second degree type 1
Second degree type 2
Third degree
What is a subcategory of type 1 second degree heart blocks?
Wenckebach
First degree heart block
Regularity
Depends on underlying rhythm
First degree heart block
Rate
Depends on underlying rhythm
First degree heart block
P waves
Upright
Uniform
First degree heart block
PRI
Greater than .20 constant
First degree heart block
QRS
Less than .12
With second degree heart blocks what gets depolarized more; atria or ventricles?
Atria because the AV node blocks some impulses from being conducted to ventricles
What is variable conduction?
The ratio of P waves to QRS completes change across a strip
2:1 3:1 3:1 2:1
Type 2 second degree heart block
Regularity
RRI can be regular or irregular
PPI is regular
Type 2 second degree heart block
Rate
Usually bradycardia can be one half to one third the normal rate
Type 2 second degree heart block
P waves
Upright uniform
More P waves than QRS complexes
Type 2 second degree heart block
PRI
Constant
Can be greater than .20
Type 2 second degree heart block
QRS
Less than .12
What happens to PRI in Wenckebach 2nd degree heart blocks?
The PRI get progressively longer until you don’t see a QRS complex
Wenckebach Type 1 second degree heart block
Regularity
Irregular
Wenckebach Type 1 second degree heart block
Rate
Slightly slower than normal
Wenckebach Type 1 second degree heart block P waves (3)
Upright
Uniform
Some p waves not followed by QRS complexes
Wenckebach Type 1 second degree heart block
PRI
Progressively longer until P wave is blocked
Wenckebach Type 1 second degree heart block
QRS
Less than .12
If the rate is 20-40 and QRS is greater than .12 where are the impulses originated?
Ventricles
If the rate is 40-60 and the QRS is less than .12 where are the impulses originated?
AV junction
What occurs when two pacemakers control the upper and lower chambers of the heart without regard for each other?
Atrioventricular dissociation
What is the relationship of p waves and QRS complexes in complete heart blocks?
There is no relationship between the two
What is the distinction between Wenckebach and complete heart blocks?
The RRI in complete heart blocks are regular
The RRI in Wenckebach are irregular
Third degree heart block
Regularity
Regular
Third degree heart block
Rate
AR normal
VR 40-60 if junctional 20-40 if ventricular
Third degree heart block P waves (3)
Upright
Uniform
More p waves than QRS complexes
Third degree heart block
PRI
No relationship between p waves and QRS complexes
Third degree heart block
QRS
Less than .12 if junctional
More than .12 if ventricular
What is a heart block?
The result of conduction disturbances in the AV node
