4093 6 Flashcards
What are 3 of the ways we evaluate an ECG
P wave shape
P R interval
QRS complex duration and shape
Where do you find the PR interval on the strip
from the beginning of the P to the beginning of the Q
The size of the PR interval reflects the
amount of time from the start of atrial depolarization to the start of ventricular depolarization
The normal time for PR interval is:
0.12 – 0.20 seconds (3 to 5 small boxes)
or the most part, Sinus dysrhythmias either effect the
rate or rhythm. The other stuff will be normal. So sinus dysrhythmias look similar to NSR
Sinus Rhythm is the only rhythm when
each of the five steps of rhythm analysis are “normal”
1500 method
count the little boxes between the peaks and divide into 1500
If Sinus tachycardia gets really fast, which one of the measurements are you unable to do
you can’t do the PR interval because the P is overtaken by the preceding T
Sinus Dysrhythmia often occurs as a
normal variant (can be in young people, athletes)
Sinus Dysrhythmia is frequently related to ____ and
breathing and pressure on the vagas nerve
Sinus Arrest occurs when
there’s sudden absence of electrical activity starting in the SA node
Sinus Arrest: A pause of ___-seconds is considered a medical emergency
six-seconds
Sinus Exit Block looks very much the same as
Sinus Arrest with one important distinction: with Sinus Exit Block the pause is a direct multiple of the R to R interval of the underlying rhythm. So it’s more orderly
PAC’s occur when
an early electrical impulse occurs from a location in the atria other than the SA node
PAC’s occur when an early electrical impulse occurs
from a location in the atria other than the SA node
PAC: because the signal is being fired from somewhere unusual, it results in a change in the shape of the
P wave (the shape might be fine, but it could be bisphasic)
The P wave with PAC’s will always be
upright
PAC: the R to R intervals could be
irregular
Atrial Flutter occurs when there is an obstruction within the
atrial electrical conduction system
Atrial Flutter occurs when there is an obstruction within the atrial electrical conduction system. Due to this impediment a series of
rapid depolarizations occur.
Atrial Fibrillation: P waves
are absent
What measurement can you not do in Atrial Fibrillation
PR interval (because there’s no P wave)
Atrial Fibrillation: rapid electrical activity overwhelms the AV node causing impulses to
enter the ventricular conduction system at irregular points. This results in irregular R to R intervals.
Many times when a patient has “new onset” Atrial Fibrillation the patient will report with a heart rate of
160 bpm or more
