ECG Made Easy Flashcards
What do the letters ECG stand for?
ElectroCardioGram
What is the heart?
The heart is a pump driven by intrinsic electrical impulses which make the heart beat.
What does an ElectroCardioGram do?
An electrocardiogram is a paper recording of that electrical activity.
What does the ECG record?
The ECG records where electrical impulses start and how they flow through the heart.
What doesn’t the ECG measure?
The ECG does not measure how well the heart is pumping
Where does the electrical activity of the heart start?
It starts in the sinoatrial node
What is another name for the sinoatrial node?
The sinoatrial node is also called the internal pacemaker
Where is the sinoatrial node located?
It is located in the right atrium
What is the normal rhythm of the heart called?
It is called the sinus rhythm
What is the proper name for the normal rhythm of the heart?
It is called the sinoatrial rhythm
What is the way that electrical impulses flow through the heart called?
Conduction
What do abnormalities is the electrical activity of the heart result in?
They result in abnormal conduction or rhythms
What happens when the heart has abnormal conduction or rhythm?
It causes the heart to go too quickly, too slowly or beat irregularly
What can changes to the normal flow of electricity through the heart indicate on an ECG?
They can indicate damaged heart muscle
What are the causes of damaged heart muscle?
Infarction, hypertension and pulmonary embolism
When should an ECG be recorded?
An ECG should be recorded whenever a patient has
- chest pain
- palpitations
- breathlessness
- dizziness
- an episode of syncope
- an unexplained fall
When is it good to have an ECG for a patient who doesn’t fit the regular symptoms?
When the patient has had a stroke or a transient ischemic attack (TIA) as these may be caused by an irregular heart rhythm
What is a good practice to consider when deciding whether or not to administer an ECG to a patient?
A patient’s symptoms and physical signs will guide interpretation of the ECG
How is an ECG recorded?
Electrodes are placed on a patients limbs and chest to record different views of the heart’s electrical activity.
What is each view of the heart called?
It is called a lead
How many electrodes are required to get one view(lead) of the heart?
Two electrodes are required to get one view
How many views(leads) are required to determine the rhythm of the heart?
One view(one lead) is required to get a rhythm of the heart
How many electrodes are attached to each limb?
One electrode is attached to each limb
How many views of the heart do four electrodes attached to each limb provide?
Four electrodes attached to each limb provide six limb leads or six different views of the heart
What are the six limb leads called?
I, II, III, VL, VF and VR.
What did VL, VF and VR used to be called?
AVL, AVF, and AVR, the A is redundant.
How many electrodes are placed on the chest?
Six electrodes are placed on the chest
What are the six leads that are placed on the heart called?
V1, V2, V3, V4, V5, V6
What view of the heart do the six limb leads give us?
They give us six different views of the heart in a vertical plane
What view of the heart do the six electrodes give us?
They give us a view of the heart from the front in a horizontal plane
What is the proper placement of electrodes on the limbs?
RA (Right arm): Between the right shoulder and right elbow
RL (Right leg): Below the right torso and above the right ankle
LA (Left arm): Between the left shoulder and the left elbow
LL (Left leg): Below the left torso and above the left ankle
What is the correct electrode placement for the chest?
V1: Fourth intercostal space on the right sternum
V2: Fourth intercostal space at the left sternum
V3: Midway between placement of V2 and V4
V4: Fifth intercostal space at the midclavicular line
V5: Anterior axillary line on the same horizontal level as V4
V6: Midaxillary line on the same horizontal level as V4 and V5
What color is the earth electrode?
It is black
What is important to know about electrode placement on the limbs vs the chest?
The chest electrode placement must be accurate by the limb electrode placement can vary within the given position
In what state should the patient be when receiving an ECG?
The patient should be warm and relaxed
What machine settings are standard for an ECG machine?
Paper speed of 25mm/second
Voltage calibration should be set so that 1mV causes 1cm of upwards deflection
What important information should be recorded on the ECG?
The date, time and patient’s name
What important medical information should be recorded on the ECG?
The patient’s symptoms and BP on the ECG.
What is the mechanism of a heartbeat in a normal heart?
In a normal heart, the sinoatrial node fires regularly and the electrical impulse spreads through an anatomical path to the ventricles resulting in ventricular contractions felt as the pulse or heartbeat
What is a heart beat represented by on an ECG?
Each heartbeat is represented by one ECG complex
How many parts does an ECG complex have?
An ECG complex consists of 5 parts?
What does the P wave of the ECG complex represent?
The P wave represents electrical activation of the atrial muscle
What is a term for the activation of the atrial muscle represented by the P wave?
It is called depolarization
What is the PR interval in an ECG complex?
The time taken for the electrical impulse to spread from the atria to the ventricles through the atrioventricular node and the high speed conducting pathway called the bundle of His.
What is the QRS complex in the ECG complex?
The QRS complex records the impulse spreading through the ventricles resulting in the ventricular contraction known as a heartbeat.
In a normal heart, how many squares does it take to record the QRS complex?
It takes 3 small squares on an ECG
What is the ST segment of the ECG complex?
The ST complex of the ECG complex is the period when the ventricles are completely activated
What is the T wave of the ECG complex?
The T wave of the ECG complex is the return of the ventricular muscle to its resting electrical state.
What is another term for the T wave of the ECG Complex?
Repolarization
How is a normal heartbeat represented in the ECG complex?
A normal heartbeat is represented by one P wave, followed by one QRS complex and then one T wave.
