The Electrocardiogram

The measurement of the smallest blocks on standard ECG graph paer are:
A. 1 mm wide by 5mm high
B. 1 cm high by 1 cm wide
C. 5 mm wide by 1 mm high
D. 1 mm wide by 1 mm high

Answer: 1 mm wide by 1 mm high
Why: The small blocks are 1 mm by 1 mm, and the large block are 5 mm by 5 mm.

Lead I for the ECG tracing is the heart view between the:
A. right arm (RA) and the left arm (LA).
B. right arm (RA) and the left leg (LL).
C. left arm (LA) and left leg (LL).
D. right leg (RL) and the left leg (LL).
E. left arm (LA) and the right leg (RL

Answer: right arm (RA) and the left arm (LA).
Why: Leads I,II, and III are the standards limb leads; they are also known as bipolar leads. Lead I is designated as the first lead starting at the top of the body with both arms.

In a standard ECG lead V3 is located:
A. at the midaxillary line at the horizontal level of position V4 and position V5.
B. at the fifth intercostal space and left midclavicular line.
C. midway between position V2 and position V4.
D. at the fourth interco

Answer: midway between position V2 and position V4.
Why: After the location of V2 and V4 have been determined V3 is located on an imaginary line midway between V2 and V4.

Proper preparation of the patient includes the following EXCEPT:
A. nylon hose should be removed to expose the area of the legs where the sensors will be placed.
B. place the electrodes or sensors over bony prominence's of the arms and legs where the elec

Answer: place the electrodes or sensors over bony prominences of the arms and legs where the electrical activity is more easily conducted.
Why: Electrodes or sensors should be placed over fleshy muscular parts of the upper arms and lower legs. Conduction

The height of a normal standardization mark on an ECG tracing is:
A. 5 mm
B. 10 mm
C. 20 mm
D. 25 mm

Answer: 10 mm
Why: A normal standardization mark that marks the accuracy of the ECG machine should be 10 mm high. The mark should have a square top. Most ECG machines automatically place a standardization mark at the beginning of the tracing. To manually

AC interference is an artifact in an ECG tracing that means:
A. the patient is having a muscle tremor.
B. there is a loose electrode connection.
C. there is electrical interference in the room.
D. the electrodes are too tight on the patient.
E. the patien

Answer: there is electrical interference in the room.
Why: There may be electrical machines,computers or other devices causing interference with the function of the ECG machine. It may be necessary to unplug other appliances or equipment in the room or th

The cardiac testing procedure that requires the patient to keep a diary of daily activities is a (n):
A. cardiac stress test.
B. echocardiogram.
C.12-lead electrocardiogram.
D. Holter monitor.

Answer: Holter monitor.
Why: The Holter monitor is a small portable ECG device that a patient wears while continuing with daily activities. Usually a 24-hour period is adequate to record and monitor the hearts activity. The patient maintains a written dia

The ECG grounding lead is the lead attached to the:
A. right arm.
B. left arm.
C. right leg.
D. chest midway between V2 and V4.
E. left leg

Answer: right leg.
Why: The grounding lead helps to reduce alternating current (AC) interference. It keeps the average voltage of the patient the same as the instrument.

The ECG tracing is printed on graph paper at a standard speed for an adult of:
A. 25 mm/sec.
B. 50 mm/sec.
C. 10 cm/sec.
D. 20 cm/sec.

Answer: 25 mm/sec.
Why: Each block on the ECG graph paper represents 1 mm. When an ECG tracing is moving at a standard speed the paper is advancing at 25 millimetes (25 small squares) each second.

Lead II of the ECG tracing records the electrical activity through the heart from the:
A. right arm to left arm.
B. right arm to left leg.
C. right leg to left leg.
D. right arm to right leg.
E. left arm to left leg.

Answer: right arm to left leg.

During the electrical heart cycle repolarization refers to the:
A. recovering phase.
B. discharging phase
C. resting phase.
D. contracting phase.

Answer: recovering phase.
Why: During the heart cycle cardiac cells are exchanging positive and negative charges within the cell membranes. During repolarization negative ions are transfered to the inside of the cell and the positive ions return to the ou

The chest lead V1 is located at which intercostal space?
A. Fourth
C. Between fourth and fifth
D. Sixth
E. Third

Answer: Fourth
Why: V1 is located at the fourth intercostal space at the right margin of the sternum.

The image traced on the ECG paper is made by a:
A. pen filled with an ink cartridge.
B. needle scratching the image on the paper.
C. heated stylus tip that melts the coating of the paper.
D. felt pen.

Answer: heated stylus tip that melts the coating of the paper.
Why: The ECG paper is coated with a finish tha is heat sensitive. The stylus is heated and melts away the coating exposing the dark paper underneath. The tracing can be thick and blurry becaus

The purpose of adjusting the normal standard to one-half standard is to:
A. conserve paper.
B. enlarge the height of the patients ECG tracing.
C. decrease the size of the patients ECG tracing.
D. eliminate artifacts in the tracing.
E. ensure proper lead p

Answer: decrease the size of the patients ECG tracing.
Why: When the ECG machine setting is changed from the normal 10-mm high standard mark to one-half standard 5 mm high it decreases the size of the patients ECG tracing. This is necessary when the traci

When a patient has trouble relaxing or cannot remain still for the ECG the artifact that may occur is:
A. somatic muscle tremor.
B. wandering baseline.
C. AC interference.
D. electrode interference.

Answer: somatic muscle tremor.
Why: A somatic muscle tremor appears as a static line in between the complexes on the ECG paper. To avoid this artifact make sure the patient is comfortable and not cold. Pillows may be placed under the knees to help the pat

The type of cardiac procedure that requires the use of a treadmill is:
A. echocardiography.
B. cardiac stress test.
C. cardiac angiography.
D. 12-lead ECG.
E. Holter monitor.

Answer: cardiac stress test.
Why: A cardiac stress test is a procedure tha measures the body's response to increased demands made on the heart muscle. The patient walks on a treadmill while the ECG tracing is recorded. Some cardiac abnormalities may be ex

The medical assistant should gather all the appropriate patient data before the ECG procedure EXCEPT:
A. patients height and weight.
B. date of the patients first ECG procedure.
C. patients current medications.
D. time and date of the recording.

Answer: date of the patients first ECG procedure.
Why: It is important to know when the patient had his or her first ECG procedure. However it may be important to know when the patient had his or her last ECG. Some patients have had many electrocardiogram

The leads aVR , aVL, and a VF are the:
A. standard leads.
B. bipolar leads.
C. limb leads.
D. chest leads.
E. augmented voltage leads.

Answer: augmented voltage leads.
Why: Augmented voltage leads provide additional information about the electrical activity of the heart. They use the electrical midpoint of the three limb sensors as the negative pole and each limb sensor is considered the

The QRS complex of the ECG tracing represents:
A. atrial depolarization.
B. atrial repolarization.
C. ventricular depolarization.
D. ventricular repolarization.

Answer: ventricular depolarization.
Why: The QRS complex represents the contraction of the ventricles as positive ions enter the cells and negative ions leave them. Depolarization is the electrical activity that causes the heart to contract.

The ECG marking code that represents lead V1 is:
A. one dot.
B. one dash.
C. two dots.
D. one dash and one dot.
E. one dash and two dots.

Answer: one dash and one dot.
Why: All the chest leads V1 through V6 are identified as a dash followed by the number of dots that correspond with the number of the lead.

A long strip of QRS complexes of a certain lead used to define certain cardiac arrhythmias:
A. monitor strip.
B. stress strip.
C. rhythm strip.
D. artifact strip.

Answer: rhythm strip.
Why: A rhythm strip is run to give the physician a tracing longer than the typical lead length. This allows the physician to determine whether the patient has an abnormality that only shows up occasionally and not with each beat.

If the electrodes are too loose on the patient what artifact might you find on the ECG tracing.
A. Wandering baseline.
B. Somatic tremor.
C. AC interference.
D. Electrical interference.
E. Muscle tremor.

Answer: Wandering baseline.
Why: A wandering baseline appears a a tracing that wanders back and forth from the bottom to the top of the paper. The normal baseline should stay within the middle of the paper. Check all electrodes for proper connection. If e

The purpose of setting the ECG paper speed at 50 mm/sec is to:
A. help record rapid heartbeats.
B. increase the size of the complex on the paper.
C. help record slow heartbeats.
D. decrease the size of the complex on the paper.

Answer: help record rapid heartbeats.
Why: When a patient has a rapid heartbeat the faster speed allows the complexes to space farther apart on the paper. It is easier to determine the quality of the complexes when they are not plotted close together. Rap

The P wave represents the:
A. last waveform of the ECG complex.
B. activity of the ventricles.
C. resting phase of the heart muscle.
D. atrial depolarization.
E. ventricle repolarization.

Answer: atrial depolarization.
Why: The P wave is the first waveform of the ECG complex and represents the electrical activity that spreads from the SA node through the atria causing atrial contraction. During this time the cells are depolarizing.

What should the medical assistant tell a patient if the patient ask if he or she will feel any discomfort from the ECG procedure:
A. If you feel any shocks or electrical tingling please let me know.
B. Don't worry we do lots of these exams every day.
C. T

Answer: The ECG procedures does not hurt and does not send electricity through you.
Why: Reassure the patient that the ECG machines does not send out any electricity and that it does not hurt to have the procedure performed. The medical assistant should a