SOLUTIONS RATED A+
✔✔QT interval is the time between ... - ✔✔Beginning of QRS complex through T wave
✔✔What can be seen on a ECG strip in patients with a low serum potassium lever or
other metabolic disorders? - ✔✔A U wave occasionally can be seen as a small
waveform just after the T wave
✔✔By measuring the actual configuration and location of each wave in relation to the
other waves and to the baseline, in addition to the intervals between waves and
segments, the physician is able to do what? - ✔✔the physician is able to detect
rhythmic disturbances of the heart and identify different types of cardiac disorders.
✔✔How do you interpret an ECG? - ✔✔The horizontal axis represents time, and the
vertical axis represents amplitude. Therefore, five sequential large squares show the
record of what occurred in the heart during a time span of 1 second [5 large squares ×
0.2 seconds = 1 second]. Another way to say this is that at normal speed, the ECG
paper travels past the stylus at a rate of 25 mm per second. Voltage can be displayed
as either a positive or a negative deflection
✔✔How many electrodes are placed on the patients arms, legs, and chest? - ✔✔ten
total
one on each arm
one on each leg
six on chest
✔✔Standard leads. - ✔✔The first three leads recorded are called the standard or
bipolar leads, because they each use two limb electrodes to record the heart's electrical
activity.
✔✔How are standard lead designated? - ✔✔Roman numerals I, II, and III are used to
designate these leads
✔✔Augmented limb leads. - ✔✔These are designated augmented voltage right arm
(aVR), augmented voltage left arm (aVL), and augmented voltage left leg (aVF).
✔✔Why are these leads referred to as augmented? - ✔✔Because the electrical activity
recorded by these leads is relatively small, the ECG machine amplifies [or augments]
the electrical potential when recorded. These are all unipolar leads with a single positive
electrode that uses the right leg for grounding
✔✔The precordial, or chest, leads are ... - ✔✔unipolar and provide a transverse plane
view of the heart.
, ✔✔How must chest electrodes be placed? - ✔✔It is important to avoid placing
electrodes directly over a bony prominence.
✔✔How do you prepare the room and the patient for an ECG? - ✔✔-Warm, adjustable
lighting, and far away from noise and other electrical equipment
-Position treatment table so it is comfortable for the patient and for you to stand on one
side
-Offer a pillow for under the head and knees
-Have the patient disrobe to waist and put on the gown with the opening in front
-Place the patient in supine position after the bladder is emptied, and the patient is
rested for 10 minutes
✔✔What must the MA stress to the patient? - ✔✔Stress the importance of not moving
during the entire procedure, and assure the patient that there is no danger of shock
✔✔How does one know how to make the proper connections from lead wires to
electrodes? - ✔✔Making the proper connections is facilitated by specific lead markings
or color coding on the end of each lead wire
✔✔What should you do after giving the ECG printout to the physician? - ✔✔Once
approved, remove the leads and electrodes from the patient, assist him or her into a
sitting position, and provide assistance in getting off the table and dressing if necessary
✔✔How is standardization determined? - ✔✔Standardization is determined by an
international agreement so that an ECG can be interpreted in the same way anywhere
in the world
✔✔Stylus should deflect exactly ____ mm when standardization button is depressed. -
✔✔10
✔✔Recording of standardization would be __ mm wide and rectangular. - ✔✔2
✔✔When should standardization be performed? - ✔✔At minimum, standardization must
be performed before the first lead is recorded. Some physicians require a separate
standardization in each of the individual 12 leads
✔✔Why might the speed for an ECG recording need to be changed? - ✔✔If the
patient's heart rate is very rapid or if certain parts of the complex are too close together,
the paper may need to be adjusted to run at double speed, or 50 mm/sec. This extends
the recording to twice the normal length
✔✔How many sensitivity standards do most machines have that can be selected? -
✔✔three