Cardiac Electrophysiology, Telemetry, And EKG Basics Stokke N180
This is not about the dysrhythmias - those will be on another quiz. This is on reading the strips and what all the waves, phases, etc. Represent. As always, the normal disclaimers apply. . .
Questions and Answers
- 1.
What does phase 0 is this action potential chart represent?
- A.
Depolarization
- B.
Rapid Repolarization
- C.
Refractory period
Correct Answer
A. DepolarizationExplanation
Phase 0 in the action potential chart represents depolarization. Depolarization refers to the change in the electrical charge across the cell membrane, where the membrane potential becomes less negative or even positive. This occurs when voltage-gated sodium channels open, allowing an influx of sodium ions into the cell, leading to a rapid increase in the membrane potential. This phase is crucial for initiating the action potential and propagating the electrical signal along the neuron or muscle cell.Rate this question:
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- 2.
What does phase 1 is this action potential chart represent?
- A.
Early repolarization
- B.
Early plateau phase
- C.
Early depolarization
Correct Answer
A. Early repolarizationExplanation
Phase 1 in this action potential chart represents early repolarization. During this phase, the membrane potential starts to decrease after reaching its peak, as potassium ions begin to leave the cell. This repolarization prepares the cell for the next phase of the action potential.Rate this question:
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- 3.
What does phase 2 is this action potential chart represent?
- A.
Refractory period
- B.
Early repolarization
- C.
Plateau phase
Correct Answer
C. Plateau phaseExplanation
The correct answer is Plateau phase. In an action potential chart, the plateau phase represents a period of sustained depolarization of the cell membrane. During this phase, the cell maintains a high membrane potential, which allows for the prolonged contraction of cardiac muscle cells. This phase is important for ensuring efficient pumping of blood by the heart and is characterized by the influx of calcium ions into the cell and the efflux of potassium ions out of the cell.Rate this question:
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- 4.
What does phase 3 is this action potential chart represent?
- A.
Depolarization
- B.
Rapid repolarization
- C.
Early repolarization
Correct Answer
B. Rapid repolarizationExplanation
Phase 3 in an action potential chart represents rapid repolarization. During this phase, the cell membrane rapidly returns to its resting potential after depolarization. This is achieved through the opening of potassium channels and the efflux of potassium ions from the cell, causing the membrane potential to become more negative. Rapid repolarization prepares the cell for the next action potential and allows it to reset and be ready for further signaling.Rate this question:
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- 5.
What does phase 4 is this action potential chart represent?
- A.
Refractory period
- B.
Depolarization
- C.
Repolarization
Correct Answer
A. Refractory periodExplanation
The correct answer, refractory period, represents the phase in the action potential chart where the neuron is temporarily unable to generate another action potential. During this phase, the neuron is in a state of hyperpolarization and is unresponsive to any additional stimuli. This period allows for the proper reset and recovery of the neuron before it can be stimulated again.Rate this question:
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- 6.
In this lead strip, which is the most likely diagnosis for the bottom lead?
- A.
NS Rhythm
- B.
AV block one
- C.
Tachycardia
Correct Answer
A. NS RhythmExplanation
The most likely diagnosis for the bottom lead is NS Rhythm. This can be inferred from the fact that the other two options, AV block one and Tachycardia, are not mentioned in the lead strip. Therefore, NS Rhythm is the only possible diagnosis based on the information given.Rate this question:
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- 7.
On EKGs, the P waves represent what?
- A.
Atrial depolarization
- B.
Atrial repolarization
- C.
SA node firing
Correct Answer
A. Atrial depolarizationExplanation
The P waves on an EKG represent atrial depolarization. Depolarization refers to the electrical activation of the heart muscle, causing it to contract. In this case, the P waves specifically indicate the depolarization of the atria, the upper chambers of the heart. This electrical signal originates from the SA node, the natural pacemaker of the heart, and spreads through the atria, causing them to contract and pump blood into the ventricles. Therefore, the correct answer is atrial depolarization.Rate this question:
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- 8.
On EKGs, the PR interval represents what?
- A.
The time it takes for the atria to contract.
- B.
The time it takes for the impulse to get from the SA node (the moment it is created) to the ventricles.
- C.
Atrial repolarization
Correct Answer
B. The time it takes for the impulse to get from the SA node (the moment it is created) to the ventricles.Explanation
The PR interval on an EKG represents the time it takes for the impulse to travel from the SA node, where it is created, to the ventricles. This interval includes the time for atrial depolarization, the delay at the AV node, and the conduction through the bundle of His and the bundle branches before reaching the ventricles. It is an important measurement as it can indicate abnormalities in the conduction system of the heart.Rate this question:
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- 9.
On EKGs, the QRS interval (aka complex) represents what?
- A.
Ventricular repolarization
- B.
Ventricular depolarization
- C.
Diastole
Correct Answer
B. Ventricular depolarizationExplanation
The QRS interval on an EKG represents ventricular depolarization. Depolarization is the electrical activation of the heart muscle, causing it to contract and pump blood. The QRS complex shows the spread of electrical activity through the ventricles, leading to their contraction.Rate this question:
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- 10.
On EKGs, the T waves represent what?
- A.
Ventricular Repolarization
- B.
Ventricular Depolarization
- C.
Papillary muscle repolarization
Correct Answer
A. Ventricular RepolarizationExplanation
The T waves on an EKG represent ventricular repolarization. This means that the ventricles of the heart are resetting their electrical charge after contracting and pumping blood. The T wave is the part of the EKG that shows this repolarization phase. It is important to monitor T waves as abnormalities in their shape or duration can indicate certain heart conditions.Rate this question:
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- 11.
On EKGs, the QT interval represent what?
- A.
The amount of time it takes the ventricles to depolarize
- B.
The amount of time it takes the ventricles to repolarize
- C.
A + B
Correct Answer
C. A + BExplanation
The QT interval on an EKG represents the total amount of time it takes for both the ventricles to depolarize and repolarize. This interval is important in assessing the electrical activity of the heart and can help identify any abnormalities or potential cardiac issues.Rate this question:
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- 12.
On an EKG, each SMALL block represents how much time?
- A.
0.4 seconds
- B.
0.2 seconds
- C.
0.04 seconds
Correct Answer
C. 0.04 secondsExplanation
Each small block on an EKG represents 0.04 seconds of time. EKGs are used to measure the electrical activity of the heart, and the small blocks on the graph paper represent time intervals. By measuring the distance between these blocks, healthcare professionals can analyze the duration and regularity of the electrical signals in the heart. The small block interval of 0.04 seconds is a standard unit of time used in EKG interpretation.Rate this question:
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- 13.
On an EKG, each LARGE block represents how much time?
- A.
O.4 seconds
- B.
0.2 seconds
- C.
0.04 seconds
Correct Answer
B. 0.2 secondsExplanation
On an EKG, each LARGE block represents 0.2 seconds of time. This is a standard measurement used in electrocardiography to assess the electrical activity of the heart. The EKG graph consists of small and large blocks, with each large block representing a duration of 0.2 seconds. By analyzing the intervals between these blocks, healthcare professionals can identify abnormalities in the heart's electrical conduction system and diagnose various cardiac conditions.Rate this question:
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- 14.
A normal PR interval is _____________.
- A.
0.12 - 0.2 seconds
- B.
0.04 - 0.10 seconds
- C.
1.0 - 2.0 seconds
Correct Answer
A. 0.12 - 0.2 secondsExplanation
The PR interval is a measurement on an electrocardiogram (ECG) that represents the time it takes for an electrical signal to travel from the atria to the ventricles. A normal PR interval typically ranges from 0.12 to 0.2 seconds. This duration allows for adequate time for the atria to contract and pump blood into the ventricles before they contract. If the PR interval is shorter or longer than this range, it may indicate an abnormality in the electrical conduction system of the heart.Rate this question:
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- 15.
A normal QRS complex is _____________.
- A.
0.12 - 0.2 seconds
- B.
0.04 - 0.10 seconds
- C.
1.0 - 2.0 seconds
Correct Answer
B. 0.04 - 0.10 secondsExplanation
A normal QRS complex refers to the electrical activity that occurs in the ventricles of the heart during a heartbeat. It represents the depolarization of the ventricles and is measured from the beginning of the Q wave to the end of the S wave on an electrocardiogram (ECG). The correct answer range of 0.04 - 0.10 seconds indicates a normal duration for the QRS complex, which suggests that the electrical conduction through the ventricles is occurring within a normal timeframe.Rate this question:
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- 16.
A normal QT interval (which shows us the amount of time it takes to get the ventricles depolarized then repolarized) is _________________.
- A.
0.04 - 0.30 seconds
- B.
0.03 - 0.4
- C.
0.3 –0.44 seconds
Correct Answer
C. 0.3 –0.44 secondsExplanation
A normal QT interval, which measures the time it takes for the ventricles to depolarize and repolarize, typically falls within the range of 0.3 to 0.44 seconds.Rate this question:
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