10) EKG Flashcards
EKG
Graphic representation of the electrical impulses of the heart to ID arrhythmias
What is the path of electrical conduction through the heart?
SA node–>AV node–>Bundle of HIS–>L & R Bundle Branches–>Purkinje Fibers
What do P waves represent?
Atrial depolarization
How should a normal P wave look?
Nice & rounded
What follows a P wave?
Atrial contraction
What does the PR interval represent?
Slowing of conduction through the AV node
What does the QRS complex represent?
Ventricular depolarization followed by ventricular contraction
What does the ST segment represent?
Initiation of ventricular depolarization
How should the ST segment look?
Straight line
On a normal EKG, how should the RR interval be?
Regular
Why is a basic understanding of single-lead EKG’s necessary?
It can help a PT determine the safety of certain interventions in pt’s w/abn’s
What is a single-lead EKG used for?
To detect rate & rhythm abn’s
Can a single-lead EKG detect ischemia?
No
Where are single-lead EKG’s most commonly done?
*ICU *Step-downs *CPPT rehab
What us a twelve-lead EKG used for?
To determine ischemia or infarction
When is a 12-lead EKG ordered?
When there’s a change in pt condition or suspected ischemia
V1 & V2
Septum
V3 & V4
Anterior Left Ventricle
V5 & V6
Lateral Left Ventricle
On an EKG, what is indicated by heightened R waves & deeper S waves?
Ventricular Hypertrophy
How can ventricular hypertrophy be ID’ed on an EKG?
Look for heightened R waves & deeper S waves
True or False:Ventricular hypertrophy can be seen in both healthy & sick pt’s.
True
W/what cardiac dysfxns can ventricular hypertrophy be present?
LV dysfxn & CHF
On an EKG, what indicates myocardial ischemia?
ST depression or T wave inversion w/angina
What is ST depression or T wave inversion indicative of?
Myocardial ischemia
On an EKG, what indicates an MI?
ST elevation
What is ST elevation indicative of?
MI
Is ST elevation a medical emergency?
Yes
What length of time is 1 small box equal to?
.04sec
What length of time is 1 big box equal to?
.20 seconds
What length of time is each tick mark equal to?
3 seconds
What is one method of calculating HR?
Count # of QRS complexes in 6sec & multiply by 10
What is the square counting method good for?
Regular rhythms
How do you do the square counting method?
1) 1st thick line after QRS complex is 300 2) Count backwards in the sequence at each thick line (300-150-100-75-60-50) 3) Stop when you get to the next QRS complex. The # you’re at is the HR
Step by step approach for interpreting EKG’s:
*Are the RR intervals equal? *Does each beat begin w/a P wave? *Is every P wave followed by a QRS complex? *Is each QRS complex followed by a T wave? *Are the PR intervals equal? *Do all the QRS complexes look the same?
Characteristics of normal sinus rhythm
*P waves are constant & upright *Each P wave is followed by a QRS complex *Each QRST is followed by a O wave *PR interval is constant at .12-.2 sec *HR is 60-100bpm
What are T-wave changes indicative of?
Hyperkalemia
What do U waves represent?
Purkinje repolarization
Are U waves normal to see?
Yes but they can also be indicative of hypokalemia, hypercalcemia, & MI
What are Q waves indicative of?
Absence of electrical activity so sign of previous MI
What is a widened QT interval indicative of?
Impending ventricular arrhythmia
What is a widened QT interval commonly misdx’ed as?
Seizures
Dysrhythmia/Arrhythmia
Any rhythm other than NSR