Flipped Classroom - 3 and 5 lead EKG Flashcards
What does ECG measure?
Electrocardiography (ECG) measures electrical activity in the heart, producing waveforms that represent cardiac cycles. used to diagnose arrhythmias and detect ischemia.
Why is ECG monitoring crucial in anesthesia?
allows real-time assessment of cardiac function, helps in identifying potential complications, and enhances patient safety.
What types of ECG monitoring devices are available?
various ECG systems available, including portable devices, full-featured monitors, and telemetry systems, each serving unique roles in different clinical settings.
When is ECG monitoring essential?
procedures involving general anesthesia, sedation, or patients with known cardiovascular conditions to enable early detection of cardiac events.
What are the guidelines for ECG use according to the American Society of Anesthesiologists?
Continuous intraoperative ECG monitoring is mandatory, with no known contraindications.
What is the role of lead II and lead V5?
Lead II is standard for rhythm analysis, while V5 can
enhance detection of anterior ischemia.
What is a 3-lead ECG?
The most basic and commonly used system, utilizing three electrodes to capture heart activity.
What is a 5-lead ECG?
Provides a more detailed picture of heart function by using five electrodes to capture electrical signals from different areas of the chest.
What is a 12-lead ECG?
Offers the most comprehensive view of heart activity, typically employed in a diagnostic setting.
What is the electrode placement in a 3-lead ECG system?
In a 3-lead ECG setup, electrodes are positioned at specific anatomical locations—right arm, left arm, and left leg.
Which lead is often used as the primary lead for continuous monitoring in a 3-lead ECG?
Lead II is often used as the primary lead for continuous monitoring, as it provides optimal visualization of the PQRST complex.
What is the purpose of adding a V5 lead in a modified 3-lead ECG configuration?
Adding a V5 lead enhances the detection of ischemic changes, especially useful in a perioperative setting.
How are electrodes placed in a 5-lead ECG system?
In a 5-lead system, electrodes are placed at the same positions as in the 3-lead setup with added electrodes on the chest.
Which leads are typically used as primary leads in a 5-lead ECG system?
Typically, leads I, II, and V5 are used as primary leads, providing comprehensive coverage of the heart’s electrical activity.
What is the advantage of the 5-lead ECG system for high-risk patients?
The 5-lead ECG system offers earlier detection of cardiac issues and allows for rapid clinical intervention if needed.
What does the P wave represent in ECG waveforms?
The P wave represents atrial depolarization, the electrical signal that initiates contraction of the atria.
What does the QRS complex reflect in ECG waveforms?
The QRS complex reflects ventricular depolarization, the electrical impulse responsible for contracting the ventricles.
What does the T wave indicate in ECG waveforms?
The T wave indicates ventricular repolarization, the process of the ventricles returning to a resting state before the next heartbeat.
What issues can ECG help detect?
ECG helps detect arrhythmias, myocardial ischemia, conduction abnormalities, pacemaker malfunctions, and electrolyte imbalances.
What does ST Depression (>1 mm, 80 msec after J-point) indicate?
High likelihood of myocardial ischemia.
What does ST Elevation (>1 mm, 80 msec after J-point) suggest?
Suspicion of acute myocardial infarction (STEMI).
What is the J-point?
The point where the QRS complex ends and the ST segment begins.
(Butterworth et al., 2022)
What are common sources of artifacts in ECG monitoring?
Common sources include patient movement, lead-wire displacement, electrocautery use, and 60-Hz interference from nearby medical devices.
What is 60-Hz interference?
It refers to electrical noise generated by nearby alternating current (AC) devices that operate at 60 Hz.
What are common sources of 60-Hz interference?
Common sources include fluorescent lights, patient monitors, computer screens, and electrosurgical devices (e.g., cautery machines).
What is a strategy for minimizing artifacts in ECG monitoring?
Proper lead placement: Clean skin, avoid bony areas, shave if needed.
Stable electrode contact: Use fresh electrodes, press firmly, replace regularly.
How can patient movement be minimized during ECG monitoring?
Minimize patient movement by stabilizing posture and using telemetry if necessary.
How can 60-Hz interference be reduced in ECG monitoring?
Keep ECG away from interfering sources as much as possible.
What is a best practice for organizing lead wires?
Securely place and avoid tangling.
What is dual lead monitoring?
Simultaneously monitoring both Lead II and V5 improves detection capability and ensures comprehensive analysis of the heart’s rhythm.
Why is proper electrode placement important?
It’s critical to ensure electrodes are placed correctly and securely adhere to the skin’s surface to minimize movement artifacts.
How can conductive gel enhance ECG monitoring?
Applying conductive gel can enhance electrode-skin conductivity, crucial for obtaining optimal signal quality in ECG monitoring.
Which of the following statements about ECG lead selection are correct? (Select all that apply)
A. Lead II is commonly used for arrhythmia detection.
B. Lead V5 is optimal for detecting ischemia in the anterior and lateral walls.
C. A modified V5 lead can be achieved using a 3-lead system.
D. The standard 3-lead system provides the most comprehensive ischemia monitoring.
E. The best ECG lead for ischemia detection is always Lead I.
Correct Answers:
● A,B,C
Rationales:
● Lead II aligns with the heart’s electrical axis, providing the best P-wave visibility, making it ideal for detecting arrhythmias.
● Lead V5 is positioned over the 5th intercostal space at the anterior axillary line, making it highly sensitive for ischemia detection in the anterior and lateral walls of the heart.
● In a 3-lead system, the LA electrode can be repositioned to the V5 location to provide better ischemia monitoring (CS5 configuration).
● The 3-lead system is primarily used for basic arrhythmia detection, while 5-lead ECG provides better ischemia monitoring due to additional precordial lead placement.
● Lead I is not the most sensitive for ischemia. Instead, Lead V4 and V5 are more effective for detecting ischemic changes.
How can ECG signal quality be improved? (Select all that apply)
A. Ensuring proper electrode placement
B. Using conductive gel to lower skin resistance
C. Positioning lead wires parallel to power cords
D. Selecting an appropriate filter setting for motion artifacts
E. Avoiding the use of a precordial lead
Correct Answers:
* A,B,D
Rationales:
● Correct placement prevents signal distortion and improves lead accuracy.
● Conductive gel enhances electrical conduction between the skin and electrode, reducing impedance.
● Lead wires should be positioned perpendicularly to power cords to minimize 60-Hz interference.
● Using low-pass or notch filters can help reduce motion artifacts while preserving key ECG features.
● Precordial leads (e.g., V4, V5) enhance ischemia detection, so avoiding them would reduce diagnostic accuracy.
What are common causes of ECG artifacts? (Select all that apply)
A. Patient movement
B. Electrocautery interference
C. Faulty electrodes
D. Low heart rate
E. 60-Hz electrical interference
Correct Answers:
* A,B,C,E
Rationales:
● Patient movement can create motion artifacts, leading to false readings on the ECG.
● Electrical signals from surgical cautery can disrupt ECG signals, creating artifacts.
● Poor electrode contact, dried gel, or disconnected leads can cause erratic readings.
● Alternating current (AC) devices operating at 60 Hz (in the U.S.) or 50 Hz (in other regions) can cause interference in ECG readings.
Which ECG lead combination provides the highest sensitivity for detecting myocardial ischemia?
A. Lead I and Lead II
B. Lead II and Lead III
C. Lead II and Lead V5
D. Lead V1 and Lead V4
Correct Answer
* C
Rationales:
● Lead II is best for arrhythmia detection, while Lead V5 is most sensitive for anterior and lateral wall ischemia. * Studies show that monitoring Lead II + V5 can detect up to 85% of ischemic episodes.
What is the primary function of the 3-lead ECG system in anesthesia?
A. Continuous ischemia monitoring
B. Basic arrhythmia detection
C. Comprehensive cardiac assessment
D. Diagnosing complex conduction abnormalities
Correct Answer:
* B
Rationales:
* 3-lead ECG is mainly used for basic rhythm monitoring (arrhythmia detection).
* 5-lead or 12-lead ECG is needed for more detailed ischemia or conduction abnormality analysis.
* Comprehensive cardiac assessment requires a full 12-lead ECG.
A 62-year-old male with a history of hypertension and diabetes is scheduled for an elective laparoscopic cholecystectomy. During preoperative evaluation, he reports experiencing exertional chest discomfort over the past few weeks. A preoperative ECG shows 1.5 mm ST-segment depression in leads V4 and V5, recorded 80 msec after the J-point.
What is the most likely cause of this ECG finding, and what should be the next step in management?
A. Normal variant, proceed with surgery without further testing
B. Myocardial ischemia, consider further cardiac evaluation
C. Electrolyte imbalance, check potassium and calcium levels
D. Pericarditis, look for PR segment depression
Correct Answer:
* B
Rationales:
● ST-segment depression (>1 mm, 80 msec after J-point) is a strong indicator of myocardial ischemia, especially when seen in leads V4-V5 (which reflect the anterior/lateral walls).
● Patients with exertional chest discomfort and risk factors (HTN, DM) should be further evaluated before proceeding with elective surgery.
