Exam 1 Flashcards
What did Ludwig and Waller discover?
Heart’s rhythmic electrical stimuli could be monitored from a person’s skin
What did Kollicker and Mueller discover?
There was a motor nerve connected to the heart
Heart must have a rhythmic discharge of electricity
What did Luigi Galvani discover?
An electrical current causes a frog’s leg to kick
What can prompt an EKG to be taken?
Syncope Palpitations Chest pain Family history Regular physical
What is the electrical pathway through the heart?
SA node Internodal Pathway AV node Bundle of His Bundle branches His-Purkinje fibers
What does the P wave signify?
Atrial depolarization
Atrial contraction
What does the QRS wave signify?
Ventricular depolarization
What does the T wave signify?
Ventricular repolarization
What is the U point?
Final stage of repolarization that is seen after the T wave
Only seen in bradycardia
What is the J point?
Where the QRS line returns to baseline
What causes depolarization?
Influx of positively charged sodium ions
What causes repolarization?
Potassium flows out of cell
What causes a downward deflection on an EKG?
Wave of depolarization is flowing away from the positive skin electrode
Where is ventricular contraction shown on an EKG?
QT interval
Begins with QRS and persists until the end of the T wave
What is the pacemaker of the heart?
SA node
What parts of the heart can maintain automaticity?
SA node - 60 to 100 bpm
Atria - 60 to 80 bpm
AV node - 40 to 60 bpm
Ventricles - Less than 40 bpm
How can you tell if the P wave is working on an EKG?
Presence of a P wave
How much time is in the smallest box on EKG paper?
0.04 seconds
What are the 6 limb leads on an EKG?
I II III AVR AVL AVF
What are the 6 chest leads on an EKG?
V1 V2 V3 V4 V5 V6
How are the leads (Bipolar)placed to make the Einthoven’s triangle?
Lead 1 - RA neg, LA pos
Lead 2 - RA neg, LL pos
Lead 3 - LA neg, LL pos
What are the augmented limb leads?
AVF - LL pos, RA and LA neg
AVR - RA pos, LA and LL neg
AVL - LA pos, RA and LL neg
Where do the V1-V6 leads go?
V1 begins on the sternum and increase as they are placed laterally
Chest is positive, back is negative
Oriented through the AV node
What are the lateral leads?
I and AVL
What are the inferior leads?
II, III, and AVF
What causes the sympathetic effect on the heart?
Norepi and Epi
What causes the parasympathetic effect on the heart?
Acetylcholine
What is classified as sinus bradycardia?
40 to 60 bpm
Can occur from parasympathetic excess (conditioned atheletes)
What is classified as sinus tachycardia?
100 - 150
Can occur from sympathetic excess (exercise)
When does an irritable automaticity focus happen?
Physiological/pathological emergency
Is a sudden discharge at a rapid rate (150-250 bpm)
Hypokalemia, ischemia, and infarction
When can the 6 second strip method be used for calculating HR?
Bradycardia
What are the different methods for measuring heart rate on an EKG?
Large box method
6 second strip method
What is the normal PR interval?
0.12 to 0.2 seconds
What is the normal QRS interval?
0.06 to 0.10 seconds
