Chapter 3 - Basic Electrophysiology Flashcards
Electrocardiograph (printout)
Machine used to record the electrocardiogram.
[Power Supply, Amplifier, Galvanometer (transforms electrical energy to mechanical energy), Stylus, Patient Lead Cable, Control Panel, & Electrodes (sensors made of silver chloride, pick up heart voltage from skin)]
ECG (electrocardiogram)
Graphic representation of the electrical activity of the heart. (also provides info about heart’s function & structure)
[12 views of heart = 3 bipolar limb leads, 3 unipolar limb leads, & 6 unipolar chest leads]
Macroshock
LARGE electrical shock caused by improper or faulty grounding of electrical equipment.
Microshock
SMALL electrical shock directly to the heart.
Lead
A record of electrical activity between two electrodes. Each lead records the average current flow at a specific time in a portion of the heart.
Bipolar Leads (Standard Limb Leads)
Consists of 2 electrodes of opposite polarity.
Lead I: right arm (-) to left arm (+)
Lead II: right arm (-) to left leg (+)
Lead III: left arm (-) to left leg (+)
Einthoven’s Law
(Height of QRS) Lead I + (Height of QRS) Lead III = Lead II (tallest QRS)
Unipolar Leads (Augmented Limb Leads)
Consists of a single positive electrode & a reference point (center of electrical field of heart).
[aVR, aVL, & aVF]
Precordial/Chest Leads
Record the potential difference between the chest and the zero reference pont. [V1-6]
Lead Positions
V1 - 4th intercostal space, right sternal border
V2 - 4th intercostal space, left sternal border
V3 - Midway between V2 & V4
V4 - 5th intercostal space, midclavicular line
V5 - in line with V4, left anterior axillary line
V6 - in line with V4 & V5, left mid-axillary line
Alternate Limb Lead Positions
Required for: • Limb amputees • Fractures, casts, splints, or braces • Surgery wounds • Skin rashes or burns
Alternate Precordial/Chest Lead Placement
- Chest or thoracic surgery
- Chest trauma wounds or burns
- Chest tubes or drainage bags
