Electrocardiograph Lab 3

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Questions and Answers

Where are the electrodes placed on the chest to perform an ECG?

On the upper and lower abdomen

On the left and right shoulders

Between the fourth and fifth ribs on the left and right side of the sternum (correct)

On the back and spine

What does the P wave represent in an ECG?

Repolarization of the ventricle

Depolarization of the atrium (correct)

Repolarization of the atrium

Depolarization of the ventricle

Why is it important to check a patient's sodium levels before an ECG?

Sodium is not important for heart movement

Sodium levels affect the heart rate

Sodium levels affect the heart rhythm

Sodium is an important electrolyte for heart movement (correct)

What can an ECG help identify?

Heart rate, heart rhythm, heart attack, and blood supply to the heart Signup and view all the answers

Why does the repolarization of the atrium often disappear in the QRS complex?

Because the repolarization of the atrium is small compared to the QRS complex Signup and view all the answers

What is the purpose of using gel with ions during an ECG?

To increase conductivity Signup and view all the answers

What is the main purpose of an electrocardiograph?

To detect heart problems and monitor the heart's health Signup and view all the answers

What is the origin of electricity in the heart?

Sinoatrial node Signup and view all the answers

What is the direction of electricity measured by Lead II?

From the right arm to the left leg Signup and view all the answers

What is the electrically most important chamber of the heart?

Right atrium Signup and view all the answers

Who developed the ECG?

Einthoven Signup and view all the answers

What symptom may indicate the need for an ECG?

Chest pain Signup and view all the answers

How many electrodes are used to measure ECG in hospitals?

12 electrodes Signup and view all the answers

What is the mechanically most important chamber of the heart?

Left ventricle Signup and view all the answers

What is the primary function of an electroencephalogram (EEG)?

To measure electrical activity in the brain Signup and view all the answers

What type of waves are recorded by an EEG?

Electrical waves Signup and view all the answers

What is the frequency range of delta waves in an EEG?

3 Hz or below Signup and view all the answers

Which type of brain wave is typically seen in normal relaxed adults?

Alpha wave Signup and view all the answers

What is the purpose of an EEG in medical diagnosis?

To check the status of brain-related conditions Signup and view all the answers

What is the frequency range of beta waves in an EEG?

14 Hz or greater Signup and view all the answers

Where are the electrodes placed to perform an EEG?

On the scalp Signup and view all the answers

What happens to alpha waves when the eyes are opened or the person is alerted?

They disappear Signup and view all the answers

What is the primary purpose of an Electromyography (EMG)?

To assess the health of muscles and nerve cells Signup and view all the answers

What type of electrodes are inserted into the muscle to be tested?

Needle electrodes Signup and view all the answers

What is a common symptom that may indicate the need for an EMG?

Tingling Signup and view all the answers

What do EMG results typically help diagnose or rule out?

Muscle disorders, such as muscular dystrophy Signup and view all the answers

What is the function of surface electrodes in an EMG test?

To work on the nerve that activates the muscle Signup and view all the answers

What do motor neurons transmit in an EMG test?

Electrical signals that cause muscles to contract Signup and view all the answers

Study Notes

What is Electrocardiograph?

An Electrocardiogram (ECG) records the electrical signals in the heart.
It's a common and painless test used to quickly detect heart problems and monitor the heart's health.

Why is ECG done?

To diagnose many common heart problems, including irregular heart rhythms (arrhythmias), blocked or narrowed arteries in the heart, and previous heart attacks.
To monitor heart disease treatments, such as pacemakers.

Indications for ECG

Chest pain
Dizziness, lightheadedness or confusion
Heart palpitations
Rapid pulse
Shortness of breath
Weakness, fatigue or a decline in ability to exercise

Heart's Electrical Activity

The sinoatrial node, located in the right atrium, is the origin of electricity of the heart.
The electrical activity is sent to the atrioventricular node and then to the purkinjee fibers of the heart.
Electrically, the most important chamber of the heart is the right atrium.
Mechanically, the most important chamber of the heart is the left ventricle.

ECG Leads

Einthoven's triangle has three leads:
- Lead I: direction of electricity from the right arm to the left arm.
- Lead II: direction of electricity from the right arm to the left leg.
- Lead III: direction of electricity from the left arm to the left leg.
Lead II is important because it directs the electrical pulse from the right atrium to the left ventricle.

Measuring ECG

Hospitals use 12 electrodes to measure ECG:
- Right arm, left arm, right leg, left leg, and 8 electrodes between the 4th and 5th ribs on the left and right side of the sternum.
A single electrode is positioned between the 4th intercostal space.

ECG Waves

P wave: indicates depolarization of the atrium.
QRS complex: series of waves that indicate depolarization of the ventricle.
T wave: represents repolarization of the ventricle.

Important to Know

The repolarization of the atrium is small and will disappear in QRS complex.
Gel containing ions can be used to increase conductivity during ECG.
Sodium is an important electrolyte for the heart movement, and checking the patient's electrolyte levels is important.

What do the Results Tell Us?

Heart rate: ECG can help identify an unusually fast heart rate (tachycardia) or an unusually slow heart rate (bradycardia).
Heart rhythm: ECG can detect irregular heartbeats (arrhythmias).
Heart attack: ECG can show evidence of a previous heart attack or one that's currently happening.
Blood and oxygen supply to the heart: ECG can provide information about this.
Heart structure changes: ECG can provide clues about an enlarged heart, heart defects, and other heart problems.

What is Electroencephalogram (EEG)?

An EEG is a test that measures electrical activity in the brain using small metal discs (electrodes) attached to the scalp.

What Does EEG Record?

The waveforms recorded by EEG reflect the activity of the surface of the brain and brain cortex.
EEG records electrical impulses of the brain sent via electrodes placed on the head to an amplifier.

Types of Brain Waves

Delta Waves

Frequency: 3 Hz or below
Highest in amplitude and slowest waves
Normal in infants up to one year and in stages 3 and 4 of sleep

Theta Waves

Frequency: 3.5 to 7.5 Hz
Classified as "slow" activity
Normal in children up to 13 years and in sleep, but abnormal in awake adults

Alpha Waves

Frequency: 7.5 to 13 Hz
Usually seen in posterior regions of the head on both sides
Appears when closing the eyes and relaxing, and disappears when opening the eyes or alerting

Beta Waves

Frequency: 14 Hz and greater
Classified as "fast" activity
Seen on both sides in symmetrical distribution, most evident frontally
Accentuated by sedative-hypnotic
Regarded as a normal rhythm
Dominant rhythm in patients who are alert or anxious or have their eyes open

Why is an EEG Performed?

To check the status of brain-related conditions such as epilepsy.

What is Electromyography?

Electromyography (EMG) is a diagnostic procedure to assess the health of muscles and motor neurons.
EMG results can reveal nerve dysfunction, muscle dysfunction, or problems with nerve-to-muscle signal transmission.

How EMG Works

Motor neurons transmit electrical signals that cause muscles to contract.
EMG uses tiny devices called electrodes to translate these signals into graphs, sounds, or numerical values.

Why EMG is Done

Doctors order an EMG if patients show signs or symptoms of nerve or muscle disorders, such as:
- Tingling
- Numbness
- Muscle weakness
- Muscle pain or cramping
- Certain types of limb pain

Types of EMG Electrodes

There are two major types of electrodes used to measure EMG signals:
- Needle electrodes: approximately 1 mm2 wide, inserted into the muscle to be tested
- Surface electrodes: 0.5–2.5-cm wide, non-invasive, and positioned to detect electrical activity that activates muscle movement

What EMG Results Detect

EMG results help diagnose or rule out conditions such as:
- Muscle disorders (e.g., muscular dystrophy)

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Description

Learn about Electrocardiograph (ECG), a painless test that records electrical signals in the heart to detect heart problems and monitor heart health.