Questions and Answers
What are Standard Limb Leads comprised of?
What is Lead I?
Right arm aVR to left arm aVL, with the right arm being negative and the left arm being positive.
What is Lead II?
Right arm aVR to left leg aVF, with the right arm being negative and the left leg being positive.
What is Lead III?
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What does aVR indicate?
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What does aVL indicate?
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What does aVF indicate?
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What are Bipolar Leads?
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What is Einthoven's Triangle?
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What are Unipolar Leads?
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What is an example of Frontal Plane?
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What do Left Lateral Leads monitor?
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What is the role of Inferior Leads?
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What do Precordial Leads monitor?
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What do V1 and V2 leads monitor?
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What do V3 and V4 leads monitor?
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What do V5 and V6 leads view?
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What do Anterior Leads comprise?
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What do Lateral Leads comprise?
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What is the duration of a Small Square on the ECG?
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What is the duration of a Large Square on the ECG?
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What does Amplitude represent in an ECG?
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What are Waveforms in an ECG?
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What are Complexes in an ECG?
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What are Segments in an ECG?
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What are Intervals in an ECG?
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How are positive ECG tracings described?
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How are negative ECG tracings described?
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What does the P wave represent?
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What is the PR interval?
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What does the QRS complex represent?
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What does the ST segment represent?
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Study Notes
ECG Lead System Overview
- Standard limb leads consist of leads I, II, III, aVR, aVL, and aVF, derived from electrodes on arms and legs.
Lead Definitions
- Lead I: Connects right arm (aVR, negative) to left arm (aVL, positive).
- Lead II: Connects right arm (aVR, negative) to left leg (aVF, positive).
- Lead III: Connects left arm (aVL, negative) to left leg (aVF, positive).
Unipolar and Bipolar Leads
- Bipolar leads: Leads I, II, III use one positive and one negative electrode.
- Unipolar leads: aVR, aVL, aVF monitor heart activity between one positive electrode and a reference point.
Einthoven's Triangle
- An imaginary equilateral triangle encompassing the heart formed by the axes of the bipolar limb leads.
Heart Surface Monitoring
- Frontal plane: Monitors electrical activity from the base to the apex in a right to left direction.
- Left lateral leads: Leads I and aVL focus on the left lateral side.
- Inferior leads: Leads II, III, aVF observe the lower surfaces.
- Precordial leads: Unipolar; record electrical activity across a horizontal plane.
Precordial Lead Positions
- V1 and V2: Monitor the right ventricle.
- V3 and V4: Monitor the ventricular septum.
- V5 and V6: View the left ventricle.
Lead Classification
- Anterior leads: V1, V2, V3, V4.
- Lateral leads: V5 and V6.
ECG Measurement
- Small square: Has a duration of 0.04 seconds.
- Large square: Comprises five small squares with a duration of 0.20 seconds.
- Amplitude: Represented by the vertical portion of each small square.
ECG Waveforms and Segments
- Waveforms: Begin and end at baseline.
- Complexes: Composed of two or more waveforms.
- Segments: Flat, isoelectric lines.
- Intervals: Combination of waveforms or complexes with segments.
ECG Wave Characteristics
- Positive deflections: Represented by ECG tracings above the baseline.
- Negative deflections: Occur below the baseline.
Specific Wave Details
- P wave: Indicates atrial depolarization; symmetric and upright shape; amplitude of 0.2 to 0.3 mV.
- PR interval: From the start of the P wave to the beginning of the QRS complex; normal duration is 0.12 to 0.20 seconds.
- QRS complex: Represents ventricular depolarization; duration is typically less than 0.12 seconds.
- ST segment: Time between ventricular depolarization and repolarization; measures 0.12 seconds or less, starts at the J point.
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Description
Test your knowledge of the ECG lead system with these flashcards. Each card covers different standard limb leads and their definitions, providing a comprehensive review of Chapter 13 concepts. Perfect for students preparing for exams on ECG interpretation.