Artifact
Additional electrical activity picked up by the ECG that interferes with the normal appearance of the ECG cycles
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
Baseline
The flat horizontal line that separates the various waves of the ECG cycle
Cardiac cycle
One complete heartbeat
Dysrhythmia
An irregular heart rate or rhythm
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
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 electrocardiograph
Interval
The length of a wave or the length of a wave with a segment
Ischemia
Deficiency of blood in a body part
Normal sinus rhythm
Refers to an electrocardiogram that is within normal limits
Segment
The portion of the ECG between two waves
Purpose of electrocardiography
To evaluate chest pain, shortness of breath, dizziness, or heart palpitations, to detect dysrhythmia, to detect cardiac ischemia, to help diagnose damage to the heart caused by a MI, to determine the presence of hypertrophy of the heart, to detect myocard
Why is the R wave taller than the P wave ?
The ventricles are larger than the atria and therefore require a stronger electrical stimulus to deplolorize the ventricles
Why does atrial repolarization not appear as a separate wave on the ECG cycle?
It occurs at the same time as ventricular depolorization. It is masked by the QRS complex
Why is the baseline flat following the U wave?
Because it is when the entire heart returns to its resting or polorized state
What changes occur on the ECG due to coronary artery disease?
A depressed S-T segment and inverted T wave
What changes occur with a myocardial infarction?
A larger than normal Q wave and an elevated S-T segment
What is the purpose of standardizing the ECG?
It's a quality control measure that ensures an accurate and reliable recording
How high should the standardization mark be when the ECG is standardized?
10mm
What is a lead and what information does it provide?
It's a tracing of the electrical activity of the heart between two electrodes. Each lead provides an electrical photograph of the hearts activity from different angle.
What is the function of an electrode?
The electrical impulses given off by the heart are picked up by electrodes and conducted into the machine through lead wites.
Why must an electrolyte be used when recording an ECG?
Because skin is a poor conductor of electricity and an electrolyte facilitates the transmission of the hearts electrical impulse.
What is the difference between a three channel and a single channel ECG?
A three channel can record through three leads simultaneously while a single channel can only record one lead at a time. The three channel can be produced in less time.
What is the purpose of teletransmission capabilities?
They can transmit a recording performed at an office electronically to an ECG data interpretation site
What is the purpose of interpretive capability?
It has a built in computer program that analyzes the recording as it is being run. It provides immediate information on the hearts activity.
What is the purpose of EMR connectivity?
It allows the ECG machine to be linked with the offices computer system.
Why should artifacts be eliminated if they occur in an ECG recording?
The affect the quality of the recording, making it difficult to manually measure the ECG cycles . They can also sometimes cause a false positive result if it's analyzed by a computer.
What is the function of an artifact filter?
To reduce artifacts when all else fails
What are possible causes of muscle artifacts?
An apprehensive patient, patient discomfort, patient movement , a physical condition
What are causes of wandering baseline?
Loose electrodes, dried out electrolyte, body creams, oils, or lotions, excessive movement of the chest wall during respiration
What are causes of 60 cycle interference artifacts?
Lead wires not following body contour, other electrical equipment in the room, wiring in the walls, ceilings or floors, improper grounding of the ECG
What are uses for a Holter monitor?
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
What are examples of cardiac dysrhythmias?
Atrial premature contraction, paroxysmal atrial tachycardia, atrial flutter, atrial fibrillation, premature ventricular contraction, ventricular tachycardia, ventricular fibrillation
Premature atrial contraction
Premature heart beat in the atria
Paroxysmal atrial tachycardia
Abnormally fast heartbeat originating in the atria with episodes beginning and ending abruptly
Atrial flutter
The atria quiver which causes the ventricles to beat irregularly
Atrial fibrillation
Irregular and often rapid heart rate that causes poor blood flow to the body. The atria beat chaotically and out of coordination with the ventricles.
Premature ventricular contraction
Extra, abnormal heartbeats beginning in the ventricles that cause skipped beats
Ventricular tachycardia
A fast but regular heart rhythm that starts in the ventricles
Ventricular fibrillation
Heart beats with rapid erratic electrical impulses causing ventricles to quiver uselessly instead of pumping blood