Control panel ekg
V2
4th intercostal space, left sternal border
V1
4th intercostal space, right sternal border
V4
5th intercostal space, left of the midclavicular line
Main power switch (off/on)
Allow for a warm-up time (as specified by the manufacturer) before using.
Sensitivity control
Allows the operator to increase or decrease the recording size to enlarge or shrink the deflections to fit on the paper. When changing from the international standard of sensitivity 1 to sensitivity 1⁄2 or sensitivity 2, the operator must include a standard for the interpreter information.
Standard button
Allows verification of calibration to the international standard.
ten sensors, or electrodes
Are placed on bare skin to record
white coat" syndrome
Be aware that many patients have elevated blood pressure readings just from being in a medical environment. This phenomenon is referred to as "white coat" syndrome.
Stylus control
Centers the recording in the middle of the page or the center of each channel by moving the stylus.
60-cycle or AC (alternating current) interference
Electrical current in wires and equipment may be picked up by the patient's body and the recording machine. This appears in the recording as small regular spikes or static, and is caused by improper grounding, nearby electrical equipment in use, or twisted and coiled lead wires. Ground the machine properly. Unplug other electrical equipment in the area. Move the machine to an interior wall outlet away from outlets containing other cables. You may have to wait until a procedure in an adjacent room, such as an X-ray, is completed (
Examples
For example, a patient in a cast up to the knee requires that both sensors be placed above the knee. If a hand and forearm are amputated, both arm sensors must be placed on the upper arm.
Stylus heat control
Increases or decreases heat and adjusts for the sharpest tracing by the stylus. This control is seen on older models, but newer machines use an ink cartridge instead of a heat stylus.
Marker
Indicates, by a code, which lead is being recorded.
Preparation for ekg
Instruct the patient to relax, breathe normally, and refrain from speaking during the procedure.
V5
Left of the anterior axillary fold, in line with V4
V6
Left of the midaxillary, in line with V4 and V5
Broken recording
Loose or broken lead wires cause the stylus to thrash erratically and to go off the page, leading to broken recording. Repair the wires, replace them, or call for service on the equipment
Newer machines
Many newer machines use an ink cartridge to supply the stylus and provide a longer-lasting printout.
V3
Midway between V2 and V4
Preparation for ekg
Prepare the patient's skin for electrodes by wiping the areas with alcohol swabs. Shave excessively hairy areas using a razor, if necessary.
time
Recorded horizontally
Voltage
Recorded vertically
Artifacts
Somatic tremor —This artifact is caused by a tense muscle or a muscle contraction, even one that you cannot see. This muscular activity causes unwanted stylus movement while the ECG is recording. It may result from patient discomfort, tension, chills, talking, or moving. Calm and reassure the patient. Suggest that the patient relax, breathe normally, and not talk. If necessary, place the patient's hands, palm side down, under the hips. This is especially helpful if the patient is not relaxed on the narrow table. This position is also best for patients with a tremor disorder. They will display the smallest number of artifacts in this position
The RL sensor
Stands for Right Leg serves as an electrical reference point and is not actually used in the recording
Lead selector
This determines from which sensors the machine will record
Record switch
This switch moves the paper at the international standard "run 25" speed (25 mm/sec). Another option is "run 50" (50 mm/sec, or twice as fast). This is used when the heart rate is so rapid that interpretation requires that it be stretched out. This is only used for detailed interpretations because it tends to waste paper and can be more difficult to read.
Artifacts in ekg
Wandering baseline —Baseline sway and baseline shift (Figure 50-11) are caused by poor sensor contact with the skin, such as when sensors are dirty or applied too tightly or too loosely, when lotion or talcum prevents good contact with the skin, or when the patient cable slips toward the floor and pulls on the lead wires. You must readjust, reapply, or clean the sensors and place the patient cable securely on the table. You may need to clean the skin with alcohol or shave chest hair to allow proper sensor skin contact.
The sternal border
border of the sternum, or breastbone
The midaxillary line
imaginary vertical line that runs from the center of the armpit.
The midclavicular line
is an imaginary vertical line that runs through the middle of the clavicle, or collarbone
The ECG
is often performed in an exam room with the patient supine (lying on the back) on the exam table.
Electrocardiogram paper
is pressure and photo sensitive and must be handled carefully. If this paper is exposed to light for long periods, the markings will fade.
anterior axillary fold
is the fold at the front of the armpit
Chest sensors
known as precordial leads
When checking the ECG machine
plug the machine into a properly grounded outlet on an interior exam room wall
"Time" markers
referred to as 3-second markers, are printed on all ECG paper. Look for them at the top of single-channel paper and between channels in multichannel paper
An intercostal space
space between ribs
The chest sensor, abbreviated with V, is used in six locations
with a number following the V, as in V1, V2, and so forth.
If you have a patient on whom you cannot place one extremity sensor as planned
you must place the sensors on both extremities symmetrically.