Multiple Choice Questions (MCQs)
- What does electrocardiography record?
a) Mechanical contraction of the heart
b) Electrical changes during the cardiac cycle
c) Blood flow through the heart chambers
d) Sound waves produced by valve closure
Answer: b) Electrical changes during the cardiac cycle - Who first recorded an ECG using bipolar leads?
a) William Harvey
b) Willem Einthoven
c) Henry Dale
d) Claude Bernard
Answer: b) Willem Einthoven - What type of deflection is produced when the depolarization wave moves towards the positive electrode?
a) Downward deflection
b) Straight line
c) Upward deflection
d) Inverted deflection
Answer: c) Upward deflection - Which factors affect the magnitude of deflection in an ECG?
a) Electrical resistance of the wires
b) Thickness of the muscle and proximity of the electrode
c) Speed of blood flow and heart rate
d) Presence of murmurs and sound waves
Answer: b) Thickness of the muscle and proximity of the electrode - What does isoelectric activity on an ECG indicate?
a) Complete cardiac depolarization
b) Electrical activity moving parallel between positive and negative electrodes
c) Ventricular contraction
d) High cardiac output
Answer: b) Electrical activity moving parallel between positive and negative electrodes - What type of deflection is produced when the repolarization wave moves away from the positive electrode?
a) Upward deflection
b) Downward deflection
c) Straight line
d) Flattened wave
Answer: a) Upward deflection - What is the primary advantage of ECG?
a) It is non-invasive and easy to interpret
b) It directly measures blood pressure
c) It visualizes cardiac muscle thickness
d) It measures oxygen saturation
Answer: a) It is non-invasive and easy to interpret - What is a lead in the context of ECG?
a) An electrical current flowing in the heart
b) A connection between electrodes and the electrocardiograph
c) A deflection wave on the ECG trace
d) A sound wave recorded by the electrocardiograph
Answer: b) A connection between electrodes and the electrocardiograph - What principle explains a downward deflection during repolarization when the wave moves towards the positive electrode?
a) Depolarization wave principle
b) Positive deflection theory
c) Basic principle of ECG recording
d) Reversal of polarity
Answer: c) Basic principle of ECG recording - What does an upward deflection on an ECG indicate about the electrical wave?
a) It is moving away from the positive electrode
b) It is moving towards the positive electrode
c) It is stationary between electrodes
d) It is a sign of cardiac ischemia
Answer: b) It is moving towards the positive electrode
Fill in the Blanks
- Willem ________ was the first to record an ECG using bipolar leads
Answer: Einthoven - An upward deflection on an ECG occurs when the depolarization wave moves ________ the positive electrode
Answer: towards - Electrical activity moving between positive and negative electrodes results in a ________ line or small deflection
Answer: straight - The ________ of the cardiac muscle affects the magnitude of deflection in an ECG
Answer: thickness - ECG is a ________ method to evaluate cardiac function
Answer: non-invasive
True or False
- An upward deflection on an ECG represents the repolarization wave moving towards the positive electrode
Answer: False - The proximity of the electrode to the muscle influences the magnitude of deflection in an ECG
Answer: True - ECG can record both depolarization and repolarization of the cardiac muscle
Answer: True - The primary advantage of ECG is its ability to measure blood flow through the heart
Answer: False - A lead represents the connection between two electrodes and the electrocardiograph
Answer: True
Subjective Questions
- Explain the basic principles of ECG recording.
Answer:- Depolarization Wave: Moving towards the positive electrode produces an upward deflection, while moving away produces a downward deflection.
- Repolarization Wave: Moving towards the positive electrode results in a downward deflection, and moving away produces an upward deflection.
- Isoelectric Activity: When electrical activity moves parallel between positive and negative electrodes, the deflection appears as a straight line or a small wave.
- Magnitude of Deflection: Depends on the thickness of the cardiac muscle and the proximity of the electrode to the muscle.
- Discuss the advantages and clinical importance of ECG.
Answer:
ECG is a non-invasive, quick, and easy-to-use diagnostic tool that records electrical changes during the cardiac cycle. It helps identify cardiac abnormalities such as arrhythmias, ischemia, and myocardial infarction. ECG is simple to interpret and provides valuable insights into the electrical activity of the heart, making it essential for diagnosing and monitoring cardiac conditions.