Module 13: EKG and Cardiovascular Testing Flashcards
Stress testing overview, role of medical assistant, and risks
Patients are attached to heart monitoring equipment while they exercise on stationary bike or treadmill. They might receive special blood flow dye thalium.
The medical assistant attaches leads and monitors vital signs throughout the procedure. They can be responsible for patient education; including pre- and post-procedure instructions
Potential risk of cardiac arrest
Holter monitoring/event monitoring overview, role of medical assistant, instructions to patient
AKA ambulatory monitoring, common in cardiology.
Instructions:
Patients assume their normal activities and keep a diary of those activities.
o) press the event monitor if they experience any cardiac symptoms or neurological symptoms.
o) do not move the electrodes.
o) avoid showers/water
o) avoid exposure to electrical forces
o) wear for 24-48 hrs
The medical assistant is responsible for attaching electrodes to trunk and providing patient education
Role of the medical assistant in cardiovascular testing
Prepping patient for procedure, providing post-procedure assistance, accurately and efficiently performing the testing, noting obvious abnormalities that need immediate intervention, maintaining equipment, preparing testing materials for provider interpretation
Instructions for a patient for EKG
Help to ensure a pleasant experience.
1) Identifying the patient using a minimum of two identifiers (NAME, DOB, last four SS, address, phone number). Ask “what is” rather than asking them to confirm
2) Explaining the procedure - harmless, records activity of the electrical system within the heart, no electrical current is sent. Only takes a few minutes, but they should not move or talk once the leads are connected. Any questions?
3) Disrobing instructions - undressed from the waist up, panty hose or tights should be removed. Drape or gown applied with opening in front. Have a light drape or blanket available to place over the patient once the leads are placed. Remove all jewelry and electronic devices - these could lead to artifacts on the EKG tracing
Multichannel vs three-channel vs single-channel EKG
Multichannel monitors all 12 leads, can record three, four, or six leads at a time
Three-channel EKG is typically found in the ambulatory care setting, records 3 leads at a time
Single channel records one at a time and produces a running strip
EKG dot matrix measurements
Small squares 1mm^2
Vertical axis: gain or amplitude, small square represents .1 MV
- normal amplitude is 10 mm or 1 mv
Horizontal axis: time, small square represents .04 s
- paper is ran at 25 mm/s
Preparing skin for electrodes, general guidelines for placement EKG (including leg amputation)
Patients should avoid applying any substance to the skin. Use alcohol wipes or soap/water at attachment sites if necessary. Clip hair if necessary, shave small areas if still necessary. If leg amputated put electrode above hips
Leads I,II, III + AVL, AVR, AVF; polarity
Leads 1, II, III are bipolar, Leads AVL, AVR, and AVF are unipolar.
Leads 1, II, and II describe impulses between the arms and legs.
Leads AVL, AVR, and AVF describe impulses from the heart to either the lower, right, or left areas of the front of the body
Describe the electrical communication between the limbs and between the limbs and the heart
Electrode placement limbs; color
Limb electrodes should be placed on fleshy areas of skin and within same general vicinity on each limb. With a leg amputation place on lower abdomen, not on bone.
In a circle:
White: right arm
Black: left arm
Red: left leg
Green: right leg
Placement of abdomen leads V1-> V6; polarity
V1: Right of sternum, fourth intercostal space
V2: Left of sternum, fourth intercostal space
V3: Between V2 and V4
V4: Left of sternum, fifth intercostal space, midclavicular line
V5: Left of sternum, fifth intercostal space, anterior axillary line
V6: Left of sternum, fifth intercostal space, midaxillary line
All precordial leads are unipolar
Location of intervals and segments EKG recording
P wave
Represents ATRIAL depolarization, small bump at beginning of graph
QRS wave
Represents VENTRICULAR depolarization/contraction (atrial repolarization occurs but is not visible), sharp spike
T wave
Represents VENTRICULAR repolarization/relaxation, large bump after QRS wave spike
U wave
Not always visible, repolarization of bundle of His and Purkinje fibers, small bump at end of graph
P-R interval
Starts at the beginning of P wave, ends at the beginning of the Q wave. Represents the time it takes from the beginning of atrial depolarization to the end of ventricular repolarization
QT interval
Starts at the beginning of the Q wave and ends at the end of the T wave. Represents the time from beginning of ventricular depolarization to the end of ventricular repolarization
ST segment
Starts at the end of S wave and ends at the beginning of the T wave. Represents the time from end of ventricular depolarization to beginning of ventricular repolarization
Proper monitoring of tracing EKG
Medical assistant should monitor to make sure leads were connected properly and that artifacts are not appearing.
Confirm universal standardization mark (indicates standard amplitude), tracking baseline, no abnormal spikes, visible P, QRS, and T waves. Waveforms should be positively deflected unless there is cardiac pathology
Precautions EKG
Take any complaints of chest pain seriously and notify provider.
Minimize risk of syncope (fainting) by having patient sit for a short while before standing
Minimize risk of dyspnea (difficulty breathing) by elevating the head to semi-Fowlers if necessary
Somatic tremor
Irregular spikes throughout tracing, related to muscle movement. Could be shivering, or Parkinson’s
AC interference
AKA 60-cycle interference, related to poor grounding or external electricity interfering with tracing (lights, computers, crossed lead wires)
Wandering baseline
Poor electrode connection. Can be associated with lotions, oils, powders
Interrupted baseline
Obvious break in the tracing, usually disconnected or broken lead wire
Artifacts definition (EKG); prevention
EKG alterations not related to cardiac electrical activity.
To reduce tremor keep patient calm, warm; have lay hands palms down under buttocks.
To reduce AC interference ensure proper grounding of the machine, use three-prong plug, avoid crossed wires, move bed from wall, turn off unnecessary electronic devices.
To avoid wandering baseline clean skin, avoid creams/lotions
Sinus bradycardia
Abnormally low heart rate (less than 60/min), not usually significant
Sinus tachycardia
Abnormally high heart rate (greater than 100/min), not usually significant
Sinus arrest
SA node failed to fire, not significant unless lasts longer than 6 seconds
Atrial flutter
Atria are contracting at a rapid rate much faster than the ventricles are contracting
Atrial fibrillation
No organized contraction of the atria; quivering state where blood clot formation is possible
Ventricular fibrillation
Ventricles are in quivering state, no discernible waves noted
Asystole
Heart stops. No noted rhythm
P wave negative deflection
Junctional dysrhythmia is likely present, typical impulse pathway from SA to AV node is not occurring. The impulse is occurring in the AV node or some other source
Premature ventricular contraction
Wide and bizarre QRS, indicates possible ventricular arrhythmia occurring
