EKG Flashcards
What do the small verticle lines represent
0.04 sec
What do the bold verticle lines represent
0.2 seconds
Isoelectric line
when positive and negative deflections are equal/cancel each other out
P wave
atrial myocyte depolarization, positive deflection, SA node depolarization NOT visual (hidden by QRS)
PR segement
plateau phase of atrical myocytes through AV node activity, NOT visual
PR intervel
time between start of P wave and start of QRS complex
What is a normal PR intervel
0.12 to .2 seconds (4-5 small boxes)
QRS complex
ventricular mycocyte depolarzation
What is a normal QRS complex
0.03 - 0.12 seconds (<1-3 small boxes)
ST segment
plateau phase of ventricular myocytes
T wave
ventricular repolarization (positive deflection)
U wave
second wave, following T wave, represents hypokalemia/drug activity
What does the atrial phase 0 correspond to
P wave
What does the ventricular phase 0 correspond to
WRS complex
What does ventricular phase 3 correspond to
T wave
Lead I
right arm (-) left arm (+)
Lead II
right arm (-) left leg (+)
Lead III
left arm (-) left leg (+)
aVR
right arm (+)
III (-)
measures bisection of I and II
aVL
left arm (+)
II (-)
measure bisection of I and III
aVF
left leg (+)
I (-)
measure perpendricular to I
V1
right, 4th intercostal
V2
left 4th intercostal
V4
left, 5th intercostal
V3
betwee V2 and V4
V5
in line with V4 and anterior axillary line
V6
in line with V4 and V5, in midaxillary line
I, II, III and aVRF will have ____ P waves and QRS complexes in NSR
positive
aVR will have ____ P waves and QRS complexes in NSR
negative
aVL will have ____ P waves and ___ QRS complexes in NSR
positive
isolectical
bradychardia
<60bpm
tachycardia
> 100 bpm
degrees of the leads
I = 0 II = 60 aVF = 90 III = 120 aVR = 210 aVL = -30
Noraml axis
Lead I and aVF both have postive QRS complexes, 0-90 degrees
Right axis deviation
Lead I has negative and aVF has postive QRS complex, 90 -180 degrees
What does right axis deviation mean
right hypertrophy, RBBB, tall, end of deep inspiration
What does left axis deviation mean
left hypertrophy, end of deep expiration, LBBB, obesity
Left axis deviation
Lead I has postive and aVF has negative QRS complex, -90 -0 degrees
What does it mean if PR interval is longer than normal
any block in AV conduction, atrial hypertrophy
What does it mean if PR intervial is shorter than normal
secondary pacemaker activity
What does it mean if you have a few very large and wide QRS complexes appearing in a lead with mostly normal QRS complexes
PVCs
What does it mean if you have very large and wide QRS complexes
RBBB, LBBB, hyperkalemia, - ventricle is producing its own beat
What happens to the HR if you increase sympathetic tone
elevate
What happens to HR if you increase activation of beta-one receptors on SA node
elevate
What happens to HR if you decrease sympathetic tone
depress
What happens to HR if you decrease activation of beta one receptors on SA node
depress
What happens to HR if you increase vagal tone
depress
What happens to HR if you increase activation of muscarinic receptors on the SA node
depress
What happens to HR if you decrease vagal tone
elevate
What happens to HR if you decrease activation of muscarinic receptors on SA node
elevate
Affect on conduction velocity through the AV node with increased sympathetic tone
increase
Affect on conduction velocity through the AV node with increased activatino of beta-one receptors on the AV node
increase
Affect on conduction velocity through the AV node with decreased sympathetic tone
decrease
Affect on conduction velocity through the AV node with decreased activation of beta one receptors on the AV node
decrease
Affect on conduction velocity through the AV node with increased vagal tone
decrease
Affect on conduction velocity through the AV node with increased activation of muscarinic receptors on the AV node
decrease
Affect on conduction velocity through the AV node with decreased vagal tone
increase
Affect on conduction velocity through the AV node with decreased activation of muscarinic receptors on the AV node
increase