EKG STUDY MATERIAL FOR ADVENTHEALTH Exam Questions And Answers.
3 pacemakers of the heart - 1. SA node
2. AV node
3. bundle branch
intrinsic rate of SA node - 60-100 bpm
intrinsic rate of AV node - 40-60 bpm
intrinsic rate of bundle branches - 20-40 bpm
electrical pathway through the heart - 1. normal conduction impulse originates in the *SA Node*
2. impulse travels to *AV Node* causing atrial depolarization (contraction)
3. AV Node slightly delays impulse then sends impulse to *Bundle of HIS*
4. then travels to *Bundle Branches*
5. impulse continues down to the *Purkinje Fibers* causing ventricular depolarization (contraction)
P wave - atrial depolarization (contraction)
PR interval - delay of AV node to allow filling of ventricles
QRS complex - ventricular depolarization (contraction)
ST interval - ventricular repolarization (resting phase)
,QT interval - ventricular depolarization and repolarization
inversely related to the heart rate
normally less than half of the length of the R-R interval
T wave - ventricular repolarization (resting phase)
isoelectric line - The baseline of the ECG / absence of electrical activity
positive deflection - a wave that exists above the isoelectric line
negative deflection - a wave that exists below the isoelectric line
absolute refractory period - cardiac cells will not respond to further stimulation
myocardial cells will not contract
electrical cells will not conduct
relative refractory period - vulnerable period
cardiac cells can be stimulated to contract
notched P wave -
peaked P wave -
inverted P wave -
depressed ST segment - indicates myocardial ischemia
, elevated ST segment - acute myocardial infarction
tall T wave - hyperkalemia
inverted T wave - myocardial ischemia
hyperacute T wave - Sometimes the earliest presentation of MI
1 small box on EKG = - 0.04 seconds
1 big box on EKG = - 0.20 seconds
5 big boxes on EKG = - 1 second
30 big boxes on EKG = - 6 seconds
normal PRI measurement - from the beginning of the P wave to the beginning of the first deflection
of the QRS complex
*NORMAL = 0.12 - 0.20*
normal QRS measurement - from the beginning of the first deflection of the QRS complex to the last
deflection of the QRS complex
*NORMAL = 0.04 - 0.10*
Lead II on EKG - negative → positive deflection
QRS is pointing up
MCL (modified chest lead) - positive → negative deflection
3 pacemakers of the heart - 1. SA node
2. AV node
3. bundle branch
intrinsic rate of SA node - 60-100 bpm
intrinsic rate of AV node - 40-60 bpm
intrinsic rate of bundle branches - 20-40 bpm
electrical pathway through the heart - 1. normal conduction impulse originates in the *SA Node*
2. impulse travels to *AV Node* causing atrial depolarization (contraction)
3. AV Node slightly delays impulse then sends impulse to *Bundle of HIS*
4. then travels to *Bundle Branches*
5. impulse continues down to the *Purkinje Fibers* causing ventricular depolarization (contraction)
P wave - atrial depolarization (contraction)
PR interval - delay of AV node to allow filling of ventricles
QRS complex - ventricular depolarization (contraction)
ST interval - ventricular repolarization (resting phase)
,QT interval - ventricular depolarization and repolarization
inversely related to the heart rate
normally less than half of the length of the R-R interval
T wave - ventricular repolarization (resting phase)
isoelectric line - The baseline of the ECG / absence of electrical activity
positive deflection - a wave that exists above the isoelectric line
negative deflection - a wave that exists below the isoelectric line
absolute refractory period - cardiac cells will not respond to further stimulation
myocardial cells will not contract
electrical cells will not conduct
relative refractory period - vulnerable period
cardiac cells can be stimulated to contract
notched P wave -
peaked P wave -
inverted P wave -
depressed ST segment - indicates myocardial ischemia
, elevated ST segment - acute myocardial infarction
tall T wave - hyperkalemia
inverted T wave - myocardial ischemia
hyperacute T wave - Sometimes the earliest presentation of MI
1 small box on EKG = - 0.04 seconds
1 big box on EKG = - 0.20 seconds
5 big boxes on EKG = - 1 second
30 big boxes on EKG = - 6 seconds
normal PRI measurement - from the beginning of the P wave to the beginning of the first deflection
of the QRS complex
*NORMAL = 0.12 - 0.20*
normal QRS measurement - from the beginning of the first deflection of the QRS complex to the last
deflection of the QRS complex
*NORMAL = 0.04 - 0.10*
Lead II on EKG - negative → positive deflection
QRS is pointing up
MCL (modified chest lead) - positive → negative deflection
