EKG Exam 1 Flashcards
What is the rate of different foci according to their origination in the heart?
SA - 60-100
Atrium - 60-80
AV Junction - 40-60
Ventricle - 20-40
What is it called when there is still electrical activity flowing through the heart but no mechanical activity?
PEA: pulseless electrical activity
Deficiencies in what ions can affect how hard the heart pumps?
Potassium, sodium, and calcium
What is the route of the electrical pathway
SA node to AV node to bundle of his to bundle branches (left and right) to purkinje
Where is SA node located
Right atrium near opening of SVC
Where is AV node located
Base of interatrial septum and extends into ventricular septum
Where is the bundle of his located
Distal to AV node and before the bundle branches
Where are the right and left bundle branches located
Intraventricular septum; carry impulses down the septum to both ventricles
Where do the purkinje fibers carry the impulse?
Up the ventricular walls, inside out; endocardium to myocardium to epicardium
Where is the issue if the QRS is wide?
Below the AV node; in the ventricle
What can a 12 lead EKG identify that a rhythm strip can’t?
Electrical axis
Bundle branch blocks
Chamber enlargement/hypertrophy
Myocardial ischemia/infarction
Long/short QT syndrome
Pulmonary embolism
Pericarditis/cardiac tamponade
In a normal EKG, I is _____ and III is _____
Positive; negative
What leads are the P wave best seen in?
II and V1
How long is the normal PR interval?
0.12-.20 seconds (3-5 blocks)
What does the PR interval signify?
Beginning of atrial fibrillation to the beginning of ventricular depolarization
What does a prolonged PR interval represent?
First degree AV block
What are the 2 criteria for a pathological Q wave
Wider than 1 small block or >1/3 as deep as R wave is high
How wide should a QRS wave be?
No more than 3 boxes (0.12 seconds)
What does a wide QRS mean?
Electrical activity is not conducting through the system and is instead traveling from myocyte to myocyte
What do ST elevations demonstrate
Myocarditis, pericarditis, LBBB, electrolyte abnormalities
What do ST segment depressions signify?
Myocardial ischemia, hypokalemia, digitalis effect
What are the septal leads
V1 and V2
What are the anterior leads
V3 and V4
What are the lateral leads
V5 and V6
RA is
Both -
LA is
+ and -
LL is
Both +
I connects
RA to LA (- to +)
II connects
LA to LL (- to +)
III connects
RA to LL (- to +)
Normal QRS axis is
-30 to +90 (or just 0-+90?)
Lead 1 positive + aVF positive
Normal axis
Lead 1 positive + lead aVF negative
Possible left axis deviation (0 to -90)
Lead 1 negative + Lead aVF positive
Right axis deviation (+90 to 180)
Lead 1 negative + aVF negative
Extreme Axis deviation (-90 to 180)
Right axis deviation (90-180) causes
LPFB
RVH
RBBB
WPW
Ventricular rhythm
Dextrocardia
Normal variant
Pathological left Axis Deviation (-30 to -90)
LAFB
LBBB
WPW
LVH
Hyperkalemia
Q-waves, MI
Pregnancy
Which leads look at the chest from the horizontal axis?
Precordial leads
V1-V6
Which leads look at the heart from the frontal axis?
Limb leads
aVR, aVL, aVF, I, II, III
Potential etiologies of AV heart blocks
Insult to AV node
MI
Digitalis toxicity
Hypoxemia
Treatment for first degree AV block
Usually none but depends on the severity
Treatment for Wenckebach
None unless symptomatic; if symptomatic consider pacemaker
Symptoms of Mobitz II
Light-headedness, dizziness, syncope, chest pain, regularly irregular heartbeat, may have bradycardia, hypo perfusion may cause hypotension
How is Mobitz II treated
Pacemaker
What are temporary pacemakers more
Sustain a patient’s heart rate in emergency situations
What is a transvenous pacemaker
An electrode is threaded through a vein and into the right atrium, right ventricle, or both
What is a transcutaneous pacemaker
Electrical current through patients chest with 2 large pads anterior/posterior; stimulates ventricular contraction
Are are the two parts of a permanent pacemaker
Generator: controls rate/strength of electrical impulse
Lead wires: relay electrical impulse to myocardium
How does a demand pacemaker work
Pacemaker fires when rate falls below 75/min; is suppressed by NSR
Indications for pacing
- Bradycardia
- Complete heart block
- Second degree Type II heart block
- Sick sinus syndrome
What ekg findings indicate ventricular pacing
A spike followed by QRS complex
Wide QRS
LBBB pattern (bc pacing typically occurs in right ventricle)
May or may not have P wave
What is Marriott’s “approximation approach” to ventricular rate
300-150-100
75-60-50
What are some causes of LBBB
Aortic stenosis
Dilated cardiomyopathy
Acute MI
Primary dz of conduction system
Lyme disease
Side effects of trauma/surgeries
