Phys 2 Physiological basis of the ECG Flashcards
Electrocardiogram
Characteristics of the ECG
Measures what?
deflections happen when?
Where do electrodes report voltage differences?
why not between the two?
What would be the deflection in each one?
Avg current flow occurs where in the heart?
What makes up your typical heart beat on an ECG?
(graph)
What is a P wave?
PR interval?
QRS complex?
ST segment?
T wave?
P wave
represents what phase of AP?
Why no repolarization seen on graph?
QRS complex
respresents what phase of AP?
Why 0 mv during ST segment?
T wave
represents what phase of AP?
what corresponds to the ending of T waves?
U wave
What is a segment?
Interval?
what does each large boxes equal horizontally?
what do they mean vertically?
The intervals?
when are they?
Segments?
when are they?
Problem?
Time between dark lines?
time between light lines?
Can calculate time between beats
(5x.2) + (2x.04)=1.08 sec
(60 sec/min)/1.08 sec = 55.5 beats/min
Standard (bipolar) limb leads use:
Augmented limb leads
Chest or precordial leads
standard limbs lead axis
What makes a deflection +?
which lead is considered positive?
If AP is spreading towards + lead of electrode set, a + deflection will be observed
Augmented limb leads axis
triangle
Chest or precordial leads
approximate locations?
what is + and - lead?
Assigned to what axis?
Lead region assignments
which lead for which part of the heart?
Physiology and anatomy
which lead and ecg placement goes with what anatomical position?
Mean electrical Axis
what is it?
uses what?
can tell us what type of problems?
what cause these problems?
MEan electrical axis
If lead I and aVF are positive?
Mean electrical axis
If lead I is negative?
potential what?
Mean electrical axis
If lead I is positive and aVF is negative?
possible anatomical finding?
Left: positive lead I and negative aVF
Left axis deviation
Right: negative lead I and positive aVF
Right axis deviation
Relationship of ECG to cadiac cycle
P wave?
QRS complex?
T wave?
