Basics Flashcards
What is Wilson’s central terminal?
It is used as a reference point on an ECG creating the augmented leads. It’s created by averaging the signals from the two limb electrodes that aren’t being used as the positive lead at the time. This provides us with additional views of the heart.
What is a P wave?
Low amplitude wave, usually positive, precedes QRS complex
What is a Q wave as part of the QRS complex?
Negative deflection, not preceded by a positive deflection (in leads I,II, V3 - V6 as well as all other leads some of the time apart from aVR)
What is a R wave as part of the QRS complex?
Positive deflection (in leads I,II, V3 - V6 as well as all other leads some of the time apart from aVR)
What is a S wave as part of the QRS complex?
Negative deflection, following a positive deflection (in leads I,II, V3 - V6 as well as all other leads some of the time apart from aVR)
What is a T wave
Broad wave, following QRS complex, may be positive or negative (depending on lead)
What does ECG stand for?
Electrocardiogram
What are leads aVR, aVL and aVF collectively referred to as?
Augmented leads
What does lead I record?
The electrical activity between the right arm and left arm, lateral view of the heart
Which ECG lead views are considered the frontal plane leads?
I, II, III, aVR, aVL, aVF (limb leads)
What is the primary view provided by the precordial leads V1 to V6?
Horizontal plane view of the heart
Which lead is placed at the 4th intercostal space at the right sternal border?
Lead V1
Which lead provides the best view of the left ventricle (anterior view)?
V5
What does the augmented vector right (aVR) lead measure?
Gives a view from the potential between the right arm and the midpoint of the left arm and left leg - Lateral view
What does aVL stand for?
Augmented vector left
What is the significance of lead V4?
It is placed at the 5th intercostal space at the midclavicular line and views the heart’s anterior wall
Which lead is most commonly used for rhythm monitoring?
Lead II
What type of information does the aVF lead provide?
It provides information from the inferior aspect of the heart
Which lead is placed at the left sternal border in the 4th intercostal space?
V2
What is the role of lead aVL?
To monitor the electrical activity from the left arm - Lateral view of the heart
What information does lead III produce?
Inferior view (calculated by analysing activity between the left arm and left leg electrodes)
What does the term ‘precordial leads’ refer to?
The leads placed on the chest to view the heart’s electrical activity in the horizontal plane.
Which lead is best for assessing right ventricular hypertrophy?
Lead V1 (septal view)
Which lead is positioned at the 5th intercostal space at the anterior axillary line?
V5
What does the P wave represent in an ECG?
Atrial depolarization
What are the 6 chest leads known as?
The precordial leads
