Electrocardiography Overview

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Questions and Answers

What is the purpose of electrocardiography?

To evaluate chest pain, shortness of breath, dizziness, or heart palpitations; to detect an abnormality in the heart's rate or rhythm; to detect the presence of impaired blood flow to the heart muscle; to help diagnose damage to the heart caused by a myocardial infarction; to determine the presence of hypertrophy of the heart; and to assess the effect on the heart of cardiac drugs.

What is the cardiac cycle?

One complete heartbeat.

Label the following components on the ECG cycle:

P wave = Atrial depolarization QRS complex = Ventricular depolarization T wave = Ventricular repolarization P-R segment = Time interval from end of atrial depolarization to beginning of ventricular depolarization S-T segment = Time interval from end of ventricular depolarization to beginning of ventricular repolarization P-R interval = Time interval from beginning of atrial depolarization to beginning of ventricular depolarization Q-T interval = Time interval from beginning of ventricular depolarization to end of repolarization

Explain what each component of the ECG cycle represents.

P wave: Atrial depolarization; QRS complex: Ventricular depolarization; T wave: Ventricular repolarization; P-R segment: Interval from end of atrial depolarization to beginning of ventricular depolarization; S-T segment: Interval from end of ventricular depolarization to beginning of ventricular repolarization; P-R interval: Interval from beginning of atrial depolarization to beginning of ventricular depolarization; Q-T interval: Interval from beginning of ventricular depolarization to end of repolarization. Signup and view all the answers

Why is the R wave taller than the P wave on the ECG graph cycle?

The ventricles are larger than the atria, requiring stronger electrical stimulation for depolarization. Signup and view all the answers

Why does atrial repolarization not appear as a separate wave on the ECG cycle?

It occurs at the same time as ventricular depolarization and is hidden by the QRS complex. Signup and view all the answers

Why is the baseline flat following the U wave?

The heart is at rest, which means there is nothing to record. Signup and view all the answers

What changes can occur on an ECG due to coronary artery disease?

Depressed S-T segment and an inverted T wave. Signup and view all the answers

What is the purpose of standardizing the electrocardiograph?

To ensure an accurate and reliable recording across different machines. Signup and view all the answers

How high should the standardization mark be when the electrocardiogram is standardized?

10 mm. Signup and view all the answers

What is a lead, and what information does it provide?

A lead is a tracing of the electrical activity of the heart between two electrodes, providing an electrical 'photograph' from a different angle. Signup and view all the answers

What is the function of an electrode?

To pick up electrical impulses from the heart and conduct them into the machine through lead wires. Signup and view all the answers

What is the function of an amplifier in ECG?

To make the electrical impulses larger for readability. Signup and view all the answers

Which electrode is used as a ground reference?

Right leg lead wire. Signup and view all the answers

Why must an electrolyte be used when recording an electrocardiogram?

To facilitate the transmission of the electrical impulse given off by the heart. Signup and view all the answers

How should electrodes be stored?

In a cool area (less than 75° F or 24° C) away from sources of heat. Signup and view all the answers

What maintenance should be performed on an ECG machine?

Clean the casing, inspect and clean cables, and check for adhesive residue. Signup and view all the answers

At what speed does the paper move while recording a normal electrocardiogram?

25 mm/sec. Signup and view all the answers

What is the difference between a three-channel and a single-channel electrocardiograph?

A single-channel electrocardiograph records from only one lead at a time, while a three-channel records three different leads simultaneously. Signup and view all the answers

What is the purpose of each of the following electrocardiograph capabilities: interpretive capability, EMR connectivity, teletransmission?

Interpretive capability analyzes the recording in real-time; EMR connectivity links to the medical office's computer; teletransmission allows recordings to be sent electronically for interpretation. Signup and view all the answers

Why should artifacts be eliminated if they occur in an ECG recording?

To produce a clear and concise ECG recording that can be interpreted accurately. Signup and view all the answers

What is the function of an artifact filter?

To reduce artifacts. Signup and view all the answers

List three possible causes of muscle artifacts.

Patient apprehension, discomfort, and movement. Signup and view all the answers

List three possible causes of wandering baseline.

Loose electrodes; dried out electrolyte; presence of body cream, oil, or lotion on the skin. Signup and view all the answers

List three possible causes of 60-cycle interference artifacts.

Lead wires not following body contour; electrical equipment in the room; improper grounding. Signup and view all the answers

List four uses of Holter monitor electrocardiography.

To assess the heart's rate and rhythm; evaluate unexplained chest pain; detect intermittent cardiac dysrhythmias; assess the effectiveness of medications. Signup and view all the answers

List examples of cardiac dysrhythmias.

Atrial premature contraction, paroxysmal atrial tachycardia, atrial flutter, atrial fibrillation, premature ventricular contraction. Signup and view all the answers

What is the purpose of a pulmonary function test?

To assess lung functioning for detecting and evaluating pulmonary disease. Signup and view all the answers

What are the indications for performing spirometry?

To assess lung dysfunction symptoms; patients at high risk for lung disease; those undergoing surgery. Signup and view all the answers

What patient preparation is required for spirometry?

No heavy meals for 8 hours; stop smoking 8 hours before; do not use bronchodilators for 4 hours. Signup and view all the answers

What is the purpose of postbronchodilator spirometry?

To inform the physician of treatment effectiveness for obstructed airways. Signup and view all the answers

What are the characteristics of asthma?

Chronic inflammation of small airways and recurrent attacks of coughing, chest tightness, shortness of breath, and wheezing. Signup and view all the answers

What are five examples of allergens that may trigger an asthma attack?

House dust, pollens, molds, animal dander, cockroach allergens. Signup and view all the answers

What are five examples of environmental irritants that may trigger an asthma attack?

Air pollutants, tobacco smoke, chemical fumes, vigorous physical exercise. Signup and view all the answers

What happens to the bronchial tubes during an asthma attack?

They constrict, swell, and become clogged with mucus. Signup and view all the answers

What is the purpose of long-term-control asthma medication?

To relieve bronchial inflammation and prevent asthma symptoms. Signup and view all the answers

What is the purpose of quick-relief asthma medication?

To quickly open the airways and prevent or control an asthma attack. Signup and view all the answers

What is the purpose of a peak flow meter?

To measure how quickly air flows out of the lungs during exhalation. Signup and view all the answers

What is the difference between a low-range and full-range peak flow meter?

Low-range meters measure values from 0 to 300; full-range meters measure values from 0 to 800. Signup and view all the answers

What is the purpose of peak flow measurements?

To monitor how well a patient's asthma is being controlled. Signup and view all the answers

Why is oxygen needed by the body?

Oxygen combines with glucose to produce energy necessary for metabolic processes. Signup and view all the answers

What occurs when the body cannot maintain an adequate oxygen level?

Progressive deterioration begins with cell death, leading to organ failure and possible death. Signup and view all the answers

What conditions may require home oxygen therapy?

Severe COPD caused by smoking, asthma, lung cancer, congestive heart failure. Signup and view all the answers

What is the purpose of the regulator and flow meter on an oxygen cylinder?

To control the flow rate of the oxygen. Signup and view all the answers

What is liquid oxygen?

Oxygen gas that has been cooled to extremely low temperatures, turning it into liquid. Signup and view all the answers

What is an oxygen concentrator?

A device that separates oxygen from the air and stores it for patient use. Signup and view all the answers

What is the primary advantage of using a nasal cannula to administer oxygen?

It does not interfere with the patient's ability to talk, eat, or drink. Signup and view all the answers

List two reasons for using a face mask to administer oxygen therapy.

To provide a high flow of oxygen; to reduce irritation from a nasal cannula. Signup and view all the answers

What occurs if oxygen comes in contact with fire?

The flame burns hotter and the fire burns faster. Signup and view all the answers

How should oxygen be stored?

In a clean, well-ventilated room away from open flames and flammable products. Signup and view all the answers

Study Notes

Electrocardiography (ECG)

Used to evaluate symptoms like chest pain, shortness of breath, and heart palpitations.
Detects dysrhythmias, cardiac ischemia, myocardial infarction damage, and hypertrophy.
Identifies myocarditis, pericarditis, electrolyte disturbances, congenital heart defects, and surgical cardiac risk.

Cardiac Cycle

Defined as one complete heartbeat.

ECG Cycle Components

P wave: Atrial depolarization.
QRS complex: Ventricular depolarization.
T wave: Ventricular repolarization.
P-R segment: Interval between atrial and ventricular depolarization.
S-T segment: Interval during ventricular repolarization.
P-R interval: Time from start of atrial depolarization to start of ventricular depolarization.
Q-T interval: Time from start of ventricular depolarization to end of repolarization.

R Wave vs. P Wave

R wave is taller due to larger ventricular size requiring stronger electrical stimulation.

Atrial Repolarization

Not visibly represented due to occurring simultaneously with ventricular depolarization, hidden by the QRS complex.

Electrocardiograph Standardization

Ensures recordings are accurate and comparable across machines; standardization mark should be 10 mm.

Electrodes and Leads

Electrodes conduct electrical impulses from the heart to the machine.
A lead provides an "electrical photograph" of heart activity.

ECG Machine Components

Amplifier: Enlarges electrical impulses.
Galvanometer: Converts amplified voltages into mechanical motion.
Thermal print head: Records heart electrical impulses on paper.

Electrode Maintenance

Right leg lead serves as a ground reference; electrolyte facilitates impulse transmission; check electrode expiration to ensure functionality.

ECG Artifacts

Artifacts must be minimized for clear readings; common causes include loose electrodes and patient movement.

Holter Monitor

Assesses heart activity during daily life; detects dysrhythmias not seen on standard ECG; evaluates medication effects.

Spirometry

Assesses lung function to detect pulmonary disease; indicated for symptomatic or high-risk patients.

Asthma Characteristics

Chronic inflammation of airways, causing cough, chest tightness, and wheezing.

Asthma Triggers

Allergens: dust, pollen, molds, animal dander.
Environmental irritants: tobacco smoke, air pollutants, cold air.

Oxygen Usage in the Body

Vital for energy production through glucose metabolism; inadequate oxygen leads to cell and organ failure.

Home Oxygen Therapy

Required for conditions like severe COPD, lung cancer, and heart failure.

Oxygen Delivery Systems

Nasal cannula: does not interfere with talking/eating.
Face masks: provide higher oxygen flow; reduce nasal irritation at night.

Oxygen Safety

Should be stored away from flames and heat; fire intensified in presence of oxygen.

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Description

Explore the fundamentals of electrocardiography (ECG), including its diagnostic uses and the key components of the ECG cycle. This quiz covers the significance of the P wave, QRS complex, and T wave, as well as the differences between R wave and P wave. Enhance your understanding of cardiac functions and interpretations through this engaging quiz.