ECG Review
What change can occur on an ECG due to a coronary artery disease?
depressed ST segment and an inverted T wave
Electrolyte
A chemical substance that promotes conduction of an electrical current.
Electrode
A conductor of electricity, which is used to promote contact between the body and the ECG
Leads V1 through V6 are known as the augmented leads. (T or F)
False (Are known as precardial leads)
The amplifier is a device placed on the skin that picks up electrical impulses released by the heart. (T or F)
False (an electrolyte is used)
A standard electrocardiogram consist of 10 leads. (T or F)
False (consist if 12 leads)
Electrodes that are too loose can cause a 60-cycle interference artifact (T or F)
False (it can cause a wandering baseline)
The P wave represents the contraction of the ventricles. (T or F)
False (represents the contraction of the atria)
The ECG is standardized, the standardization mark will be 20 mm high. (T or F)
False (the standardization mark will be 10 mm high)
Standard leads
I, II, III Record differences between arm and legs. Considered bipolar leads Have 12 leads in an ECG
What is a lead, and what information does it provide?
Is a tracing of the electrical activity of the heart between two electrodes. Provides an electrical "photograph" of the heart's activity from a different angle to provide a thorough interpretation of the heart's activity.
List three possible causes of wandering baseline.
Lose electrodes Dried out electrolyte Body creams, oils or lotions Excessive movement of the chest
Why is the R wave taller than the P wave on the ECG graph cycle?
The ventricles are larger than the atria and therefore require a long electrical stimulus to depolarize the ventricle.
A muscle artifacts can be identified by its fuzzy, irregular baseline. (T or F)
True
An ECG result that is within normal limits is said to indicate a normal sinus rhythm. (T or F)
True
An electrolyte facilitates the transmission of electrical impulses (T or F)
True
The portion of the ECG between two waves is know as a segments. (T or F)
True
When running and ECG, the medical assistant should work on the left side of the patient. (T or F)
True
-emia
blood
hypo-
deficient, below, under
-meter
measure
What is the purpose of electrocardiography?
measures and provide a visual record of the electrical activity of the heart
How high should the standardization mark be when the electrocardiogram is standardized?
10mm high and 2mm wide
At what speed does the paper move while recording normal electrocardiogram?
25 mm/sec
What is the difference between a three-channel and a single-channel electrocardiograph?
A three channel can record the electrical activity of the heart through three leads simultaneously A single channel record only one lead at a time
Artifact
Additional electrical activity picked up by the ECG that interferes with the normal appearance of the ECG cycle.
Dysrhythmia
An irregular heart rate or rhythm.
What is the purpose of an interpretive capability?
Analyzes the recording as it being run with a built-in computer program.
Why should artifacts be eliminated if they occur in an ECG recording?
Because artifacts affects the quality of the recording making it difficult to manually measure the ECG cycle; can also cause a false positive result on an ECG that is analyzed by a computer.
Why does atrial repolarization not appear as a separate wave on the ECG cycle?
Because it occurs at the same time as ventricular depolarization.
Why is the baseline flat following the U wave?
Because no electrical activity is occurring.
Why must an electrolyte be used when recording an electrocardiogram?
Because the skin is a poor conduction the electrolyte is used between the electrode and the skin to facilitate the transmission.
Atherosclerosis
Buildup of fibrous plaques of fatty deposits and cholesterol on the inner walls of an artery that causes narrowing, obstruction, and hardening of the artery.
ather/o
Combining form denoting relationship to plaque
Ischemia
Deficiency of blood in a body part
What is the purpose of an EMR connectivity?
Electronic medical record- allow the ECG machine to be linked with the office computer system.
List examples of cardiac dysrhythmias.
Extra beats Abnormal rhythm Abnormal heart rate
List three possible causes of 60-cycle interference artifacts.
Lead wires not following the body contour Other electrical equipment in the room Wiring in the walls, ceiling or floors Improper grounding of the ECG
What is the function of an electrode?
Measure and record the electrical activity generated by the heart and carried through the body. (Pick up the electrical impulses given off by the heart and conduct them through lead wires)
Cardiac Cycle
One complete heartbeat
What is the cardiac cycle?
One complete heartbeat
Q-T interval
The Q-T interval is the time interval from the beginning of the ventricular depolarization to the end of repolarization of the ventricles.
List three possible causes of muscle artifacts.
Patient discomfort Patient movement Physical condition Apprehensive (anxious) patient
What is the function of an artifact filter?
Reduce artifacts when all else false but also affects the results.
Normal sinus rhythm
Refers to an ECG that is within normal limits
P wave
The P wave represents the electrical activity associated with contraction of the atria, or atrial depolarization.
P-R interval
The P-R interval represents the time interval from the beginning of the atrial depolarization to the beginning of the ventricular depolarization.
P-R segment
The PR segment represents the time interval from the end of the atrial depolarization to the beginning of the ventricular depolarization. It is the time needed for the impulse to be delayed at the AV node and then travel through the bundle of His and Purkinje fibers to the ventricles.
QRS Complex
The QRS complex represents the electrical activity associated with the contraction of the ventricles, or ventricular depolarization.
S-T segment
The ST segment represents the time interval from the end of the ventricular depolarization to the beginning of repolarization of the ventricles.
T wave
The T wave represents the electrical recovery of the ventricles, or ventricular repolarization. The muscle cells are recovering in preparation for another impulse.
Baseline
The flat, horizontal line that separates the various wave of the ECG cycle.
ECG cycle
The graphic representation of a heartbeat
Electrocardiogram
The graphic representation of the electrical activity of the heart
Electrocardiograph
The instrument used to record the electrical activity of the heart
Interval
The length of the wave or the length of a wave with a segment
Segment
The portion of an ECG between two waves.
What is the purpose of standardizing the electrocardiograph?
The purpose of standardizing the ECG is to enable a physician see the height of a standard deflection and whether the machine is properly calibrated.
List four uses of Holter monitor electrocardiography.
To assess the rate and rhythm of the heart during daily activities To evaluate patients with unexplained chest pain, dizziness, or syncope To discover intermittent cardiac dysrhythmias not picked up on a routine resting 12-lead ECG To detect myocardial ischemia To assess the effectiveness of antidysrhythmic medications To assess the effectiveness of a pacemaker.
What is the purpose of a teletransmission?
Transmit a recording performed at the medical office electronically to an ECG data interpretation site.
Precordial leads
V1, V2,V2, V3, V4, V5, V6 In front of the heart Record the voltage from the back to the front of the heart
-gram
a record
Augmented leads
aVR(right), aVL(left), aVF(foot) Record two differences between 1 positive and 2 negatives electrodes Considered unipolar
isch/o
back, to hold back
electr/o
electricity
-sclerosis
hardening
cardi/o
heart
-graph
instrument for recording
metry
instrument used for measure
What change can occur on an ECG due to a myocardial infarction?
larger Q wave and an elevated ST segment
ox/i
oxygen
-ia
state or condition
spir/o
to breath or to breathing
