Basic EKG Flashcards
Define automaticity
The ability of the heart to generate its own spontaneous action potentials without any external stimuli
The pacemaker cells do not have a
Resting phase; once repolarization occurs, they are just slowly working on depolarizing again
Which cells make up 99% of the heart?
The contractile cells
In what order do electrolytes come into play during normal electrical conduction?
Fast na channels cause depolarization; Ca release inside the myocyte; K+ outflow to repolarize
Primary pacemaker?
The SA node
Where is the SA node located?
Back of the right atria near the superior vena cava entry
What is the function of Bachmann’s bundle?
Carries the electric impulse from the RA to the LA
What % of CO may be lost in afib?
20-25%
Afib atrial rate is _____ and ventricular rate is _____
100-300; 30-40
Intrinsic rate of AV node
40-60
Why is it important to have a delay at the AV node
To give time for the atria to contract before the ventricles and fill the ventricles with blood
How long does the AV node delay conduction?
0.1s
Another name for the bundle of His
AV bundle
Intrinsic rate of the bundle branches
20-40
Intrinsic rate of bundle of his
40-60
If you have a BBB you most likely also have
A decreased HR and BP
Intrinsic rate of Purkinje fibers
20-40
Agonal rate at Purkinje fibers
As low as 10-20
What area is most likely to take a hit with ischemia
Purkinje fibers
A strip is typically
6s
One box on EKG paper is equivalent to
0.2s
P wave
Depolarization of atria
PR interval
Represents AV conduction
QRS
Ventricle depolarization
