RMA EKG and Electrocardiography 3 — Questions and Answers
Question 1: What does the QRS complex represent on an EKG tracing?
- Ventricular depolarization (Correct answer)
- Atrial depolarization
- Ventricular repolarization
- SA node firing
Correct answer: Ventricular depolarization
The QRS complex reflects rapid depolarization of the ventricles.
Question 2: The standard paper speed for a routine 12-lead EKG is:
- 25 mm/second (Correct answer)
- 50 mm/second
- 10 mm/second
- 5 mm/second
Correct answer: 25 mm/second
Routine EKGs run at 25 mm/second, the basis for standard time measurements.
Question 3: Where should the left leg (LL) limb electrode be placed?
- Lower left leg or ankle (Correct answer)
- Upper left thigh near groin
- Left wrist
- Left lower abdomen
Correct answer: Lower left leg or ankle
The LL electrode is placed on the lower left leg, typically at the ankle.
Question 4: A standardization mark on an EKG that is 10 mm tall confirms what?
- Proper voltage calibration (1 mV = 10 mm) (Correct answer)
- Correct paper speed
- Lead reversal
- Filter is engaged
Correct answer: Proper voltage calibration (1 mV = 10 mm)
A 10 mm standardization mark verifies that 1 millivolt produces a 10 mm deflection.
Question 5: The brief flat segment between atrial and ventricular depolarization that allows ventricular filling is the:
- PR segment (Correct answer)
- ST segment
- QT interval
- T wave
Correct answer: PR segment
The PR segment reflects the delay at the AV node before ventricular activation.
Question 6: Somatic tremor artifact on an EKG is best reduced by:
- Helping the patient relax and stay warm and still (Correct answer)
- Increasing AC power
- Speeding up the paper
- Removing the chest leads
Correct answer: Helping the patient relax and stay warm and still
Somatic tremor comes from muscle activity, so relaxing and warming the patient minimizes it.
Question 7: Which structure is the heart's normal primary pacemaker?
- Sinoatrial (SA) node (Correct answer)
- Atrioventricular (AV) node
- Bundle of His
- Purkinje fibers
Correct answer: Sinoatrial (SA) node
The SA node sets the normal heart rate by initiating each electrical impulse.
RMA EKG and Electrocardiography 3
What does the QRS complex represent on an EKG tracing?