EKG Conference Flashcards
What are the 3 bipolar leads of heart?
Lead I
Lead II
Lead III
What are the unipolar leads of the heart?
aVR
aVF
aVL
What are the precordial unipolar leads of the heart?
V1 V2 V3 V4 V5 V6
What direction is the mean frontal plane vector and what is its range?
It goes down and to the left.
The normal angle of the MFP vector is from -30 degrees to 105 degrees.
Of all the leads, which one has the largest deflection and why?
Lead II. It is parallel with the to the MFP vector.
What is the PR interval of the EKG?
It is when the SA node activates the atria and then activates the AV node and the His bundle and Purkinje fibers after that.
What is the normal time range of the PR interval?
120 - 200 ms
What is the QRS complex of the EKG?
It is the activation of the ventricles.
What is the normal time range of the QRS complex?
70 - 100 ms
What is the QT interval?
It is the duration of the action potential OR the refractory period
What is the normal time range of the QT interval?
250 - 430 ms
What is the ST segment?
It corresponds with the plateau of the action potential and shifts up or down can indicate ischemia or infarction.
What is the U wave of the EKG?
It is thought to be the repolarization of the Purkinje fibers.
What makes the U wave more prominent?
Hypokalemia
What is the probable cause if all the EKG reading show very high amplitude?
Hypertrophy of the heart
What part of the cardiac cycle is lost more and more with increasing heart rate?
The diastole of the T wave to the R wave is lost more and more with increasing heart rate.
Where is lead aVR connected? What is its detection region?
Right Arm - Indetermined
Where is lead aVF connected?
What is its detection region?
Left Leg - Inferior
Where is lead aVL connected?
What is its detection region?
Left Arm - Lateral
Where is V1 connected and what is its detection region?
4th intercostal space on right - Septal
Where is V2 connected and what is its detection region?
4th intercostal space on left - Septal
Where is V3 connected and what is its detection region?
Midway between V2 and V4 - Anterior
Where is V4 connected and what is its detection region?
Left mid-clavicular line in 5th intercostal space - Anterior
Where is V5 connected and what is its detection region?
Left anterior axillary line at the level of V4 - Lateral
Where is V6 connected and what is its detection region?
Left midaxillary line at the level of V4 - Lateral
Where are the positive and negative ends of Lead I connected? What area does it detect?
Positive - Left Arm
Negative - Right Arm
Lateral
Where are the positive and negative ends of Lead II connected? What area does it detect?
Positive - Left Leg
Negative - Right Arm
Inferior
Where are the positive and negative ends of Lead III connected? What area does it detect?
Positive - Left Leg
Negative - Left Arm
Inferior
Why does repolarization appear as positive on the EKG?
It is positive because depolarization occurs where depolarization ends and goes backwards from epicardium to endocardium.
What is a right MFP vector shift?
Greater than 105 degrees
What is a left MFP vector shift?
Less than -30 degrees
In terms of vector summation, what is the equivalent of Lead II?
Lead I + Lead III
