Electrocardiographs

Question 1

Transducers

Answer 1

convert the biopotentials of the patient to electrical signals that the medical device can interpret

Question 2

Resistive Transducer

Answer 2

any element that changes its resistance as a function of a physical variable, pressure causes displacement, causes a change in resistance, moving the arm of the potentiometer

Question 3

Strain Gauge

Answer 3

Yields to stretching forces that causes changes in resistance, uses fine resistive wire

Question 4

Thermistor

Answer 4

changes resistive value in a predictable manner with changes in temperature, has a negative or positive temperature coefficient, positive coeff.: as temp increase, resistance increase, Negative coeff.: as temp increase, resistance decreases

Question 5

Solid State PN Junction

Answer 5

resistance decreases as temperature increases (negative temperature coefficient)

Question 6

Doppler Effect

Answer 6

As sound waves hit a moving object, frequency will change, the measured frequency shift is proportional to the change in velocity

Question 7

Ultrasound Transducer

Answer 7

sends sound waves with transmitter, receives reflected sound waves, converts them into electrical output, used for ultrasound monitoring

Question 8

Inductive Transducer

Answer 8

physical movements of a permeable core within an inductor Effects: iron/ferrite core inside of coil, magnetic field of the core

Question 9

Capacitive Transducer

Answer 9

causes capacitance of the transducer to vary with stimulus Uses: stationary plate or plates, moveable plate that changes position under the influence of a stimulus

Question 10

Thermocouple

Answer 10

two dissimilar conductors or semiconductors joined together at one end (junction), when the junction is heated, a potential is generated, electrons begin to flow

Question 11

Electrodes

Answer 11

a device that converts ionic potentials into electronic potentials

Question 12

Electrocardiographs (small voltage?)

Answer 12

record small voltages about 1 mV that appear on the skin surface as a result of cardiac activity

Question 13

Suction Cup Electrode

Answer 13

used for connecting portions of the body other than the extremities (head, face chest) Disadvantage: prone to movement or slippage during long recordings

Question 14

Plate Electrode

Answer 14

connected to a patient’s extremities, held in place by a rubber strap

Question 15

Column Electrode

Answer 15

reduces motion artifact generated by patient movement by eliminating electrode slippage, held in place by adhesive, used for long term applications

Question 16

Needle Electrode

Answer 16

disposable, stainless steel hypodermic needles, two to six inches in length Uses: EEG monitoring, ECG monitoring, EMG monitoring, fetal ECG monitoring,

Question 17

Bipolar Lead Configuration

Answer 17

Lead 1: measures voltage between LA and RA
Lead 2: measures voltage between RA and LL
Lead 3: measures voltage between LA and LL

Question 18

Augmented Vector

Answer 18

measures the voltage between one limb electrode and the average of the remaining two limb electrodes (indifferent electrode)

Question 19

Precordial

Answer 19

Chest electrodes labeled v1 through v6, measures the voltage between one chest electrode and the average of all limb electrodes

Question 20

electrocardiograph

Answer 20

a medical device for diagnosing diseases such as cardiac arrhythmias, conduction disorders, electrolyte imbalances, hypertension, coronary artery disease, and myocardial infarctions

Question 21

intended purpose of ECG

Answer 21

detect the electrical activity of the heart, record small voltages 1mv that appear on the skins surface

Question 22

ECG artifact

Answer 22

the wave that arises from sources other than the heart (noise)

Question 23

Asystole

Answer 23

a form of cardiac arrest in which the heart stops beating and there is no electrical activity in the heart (flatline)

Question 24

Cardiac Arrest

Answer 24

electrical malfunction of the heart that causes an arrhythmia and disrupts the pumping action of the heart

Question 25

Electrocardiogram

Answer 25

a graphic record of voltage versus time (screen or print out)of the electrical activity of the heart produced by an electrocardiograph

Question 26

Electrocardiogram

Answer 26

a graphic record of voltage versus time (screen or print out)of the electrical activity of the heart produced by an electrocardiograph

Question 27

Myocardial Infarction

Answer 27

Heart attack, circulation problem in the muscular tissues of the heart , blood is blocked from reaching the tissues of the heart

Question 28

Normal Sinus Rhythm

Answer 28

all measurements of an ECG that fall within normal limits of the characteristic of an ECG when the electrical conduction system of the heart is functioning normally

Question 29

P- Wave

Answer 29

begins with an electrical impulse from the SA node, both atria depolarize (contract) and produce electrical activity

Question 30

PR Segment

Answer 30

measures from the onset of the P-Wave to the onset of the QRS Complex, electrical impulse from atria passes to AV node, the AV node is depolarized (contracted) .12 to .20 seconds

Question 31

QRS complex

Answer 31

represents electrical impulse: travels from bundle of HIS, into bundle branches, into purkinje fibers, into the myocardial cells, causing ventricular contraction, depolarization of ventricles, represents systolic pressure

Question 32

Q- Wave R-Wave S- Wave

Answer 32

Q Wave: the first down stroke of the QRS complex R Wave: first upward deflection of the QRS complex S Wave: first downward stroke after R wave

Question 33

ST segment

Answer 33

used to identify myocardial infarctions, the interval between depolarization (S-Wave) and repolarization (T-Wave)

Question 34

T Wave

Answer 34

represents repolarization of the ventricles back to the resting state, diastolic pressure

Question 35

ECG Heart Rate using ECG

Answer 35

cardiologist can measure heart rate by measuring the R to R interval of successive QRS waves

Question 36

Electrocardiogram provides 2 key types of info

Answer 36

time intervals of an ECG and amount of electrical activity passing through the heart

Question 37

Electrocardiogram standard format

Answer 37

4 Lead configurations per line X 2.5sec of recording per lead configuration + 3 ids- holding three specific lead configurations for 10 seconds

Question 38

ECG Signals detected

Answer 38

0.05 to 100 Hz for diagnostic purposes