click below
click below
Normal Size Small Size show me how
Understanding EKGs-5
Based on the book by Beasley, 2nd Edition
Question | Answer |
---|---|
Regardless of pattern observed, what is a health professional primary concern? | The patients condition |
What is an EKG? | An electrocardiogram is a graphic representation of the heart. |
What is the machine used to record the electrocardiogram? | Electrocardiograph |
The EKG is a graphic tracing of: | The electrical activity |
Is the EKG a graphic tracing of the mechanical activity? | No |
How can the electrical activity be sensed? | Electrodes placed on the skin surface |
What depicts the heart's electrical impulses as patterns of waves on the monitor screen? | Cardiac monitor |
Why must the impulses be amplified by the EKG machine? | The electrical impulses on the skin surface are very low voltage. |
What is the printed record of the electrical activity of the heart? | Rhythm strip or EKG strip |
What is an electrode? | An adhesive pad that contains conductive gel & is designed for attachment to the patients skin |
What are leads? (Hint: 2 definitions) | 1. The color-coded electrodes are connected to the monitor or EKG machine by wires called leads.2. A pair of electrodes: check Lead I, II, MCK, etc., - Generally capitalized. |
What is necessary for the EKG machine to receive a clear picture of the electrical impulses generated by the heart's electrical conduction system? | There must be a positive (+), negative (-), and a ground lead. |
What is the purpose of the ground lead? | To minimize outside electrical interference |
What does the exact portion of the heart being visualized depend upon? | The placement of the electodes. |
Yes or No: An EKG strip analysis can obtain information on - The heart rate. | Yes |
Yes or No: An EKG strip analysis can obtain information on - Rhythm or regularity. | Yes |
Yes or No: An EKG strip analysis can obtain information on - Impulse conduction pathways. | Yes |
Yes or No: An EKG strip analysis can obtain information on - Abnormal conduction pathways | Yes |
Yes or No: An EKG strip analysis can obtain information on - Pumping action | No |
Yes or No: An EKG strip analysis can obtain information on - Cardiac output | No |
Yes or No: An EKG strip analysis can obtain information on - Blood pressure | No |
Yes or No: An EKG strip analysis can obtain information on - Cardiac muscle hypertrophy | No |
What is cardiac muscle hypertrophy? | Thickening of the heart muscle walls, typically due to abnormal cardiac symptoms such as high blood pressure. |
What is a dysrhythmia? | Abnormal rhythm of the heart |
What is a bipolar lead? | Often referred to as limb leads, the bipolar leads have one positive and one negative electrode. |
What is the most common EKG used in hospitals and clinics? | 12-lead EKG |
What type of EKG is most common in the field? | 3-lead EKG. However, a 4th lead - representing the right leg. |
Which lead is sufficient for detecting life-threatening dysrthymias? | 3-Lead EKG |
Which lead(s) are most common for cardiac monitoring because of their ability to visualize P waves? | Lead II and MCL (Modified Chest Lead) |
Which leads are bipolar leads? | Chest Leads I, II, and III. |
Which lead should be placed on the left leg? | Lead II (+) |
Which lead should be placed on the left leg? | Lead III (+) |
Which lead should be placed on the right arm? | Lead I (-) |
Which lead should be placed on the right arm? | Lead II (-) |
Which lead should be placed on the left arm? | Lead III (-) |
What is the inverted triangle formed around the heart for proper placement of the bipolar leads? | Einthoven's triangle |
What are EKG waveforms? | A wave recorded on an EKG strip that refers to movement away from the baseline. |
What is another name for baseline? | Isoelectric line |
What is deflection? | A positive or negative movement above or below the baseline or isoelectric line. |
What is a baseline? | The straight line seen on an EKG strip that represents the beginning and end point of all waves |
What is measured on the electrographic paper? | Time and amplitude (or voltage) |
What is measured on the vertical line? | Amplitude or voltage |
What is measure on the horizontal line? | Time |
How many squares = 1 mV (millivolts)? | 2 |
How is EKG graph paper divided? | Small squares, each is 1 millimeter (mm) in height and width, representing a time interval of .04 seconds. |
What do the dark lined squares represent? | 5 squares (vertically and horizontally), each representing .20 seconds (5 x .04 = .20) |
What does each of the squares represent? | The measurement of the length of time required for the electrical impulse to traverse a specific part of the heart. |
Proper interpretation of EKG rhythms is dependent upon what? | The understanding of the time increments as represented on the EKG paper. |
What causes the waveforms produced on the graph paper? | The electrical impulse after leaving the SA node |
How is one complete cardiac cycle represented on the EKG graph paper? | 5 major waves - P wave: Q, R, S waves (referred to as the QRS complex) and the T Wave |
How doe the P wave occur?(HINT: physiology in the heart) | When the SA node fires during a normal cardiac cycle, the "firing" event sends the electrical impulse outward to stimulate both atria. |
What does the P wave look like on the EKG graph paper? | The P wave is a smooth, rounded upward deflection. |
What does the P wave represent? | The P wave represents depolarization of the left and right atria |
What is the length of the P wave? | About .10 seconds in length |
What does the PR interval represent? | The PR interval represents the time interval necessary for the impulse to travel from the SA node through the internodal pathways in the atria and downward to the ventricles. |
What is an abreviation for PR? | PRI |
What does the PRI represent? | The PRI represents the distance from the beginning of the P wave to the beginning of the QRS complex. |
How is the PR measured? | 3 - 5 small squares of the EKG graph paper |
What is the time interval of the PR interval? | .12 - .20 seconds in length |
What is the QRS complex? | Q, R, S waves |
What does the QRS complex represent? | The QRS complex represents the conduction of the electrical impulse from the bundle of His throughout the ventricular muscle, or ventricular depolarization. |
Where is the Q wave? | The first downward deflection following the PRI |
Where is the R wave? | The R wave is the first upward deflection of the QRS complex and is normally the largest deflection seen in chest Leads I and II |
Where is the S wave? | The S wave immediately follows the R wave in a downward deflection. |
How is the QRS complex measured? | From the beginning of the Q wave to the point where the S wave meets the baseline. |
What is the time frame for the QRS complex? | less than .12 second or less than 3 small squares on the EKG graph paper |
Are all QRS complexes the same in every individual? | No, the QRS complex will vary from individual to individual and not all three waves are necessarily present. |
Describe the ST segment. | The time interval during which the ventricals are depolarized and ventricular repolarization begins. |
What is typical of the ST segment? | Normally the ST segment is isoelectric or consistent with the baseline. |
What may cause the ST segment to be elevated or depressed? | Cardiac diseases such as ischemia, infarction, or both. |
When does the T wave occur and what does it represent? | The T wave follows the ST segment, which represents ventricular repolarization. |
What does the T wave look like? | The T wave is normally seen as a slightly asymmetrical, slightly rounded, positive deflection. |
Is ventricular repolarization an electrical event associated with ventricular musculature? | No |
What is the T wave referred to? | The T wave is referred to the resting phase of the cardiac cycle. |
What is a refractory period? | The amount of time it takes for an excitable membrane to be ready for a second stimulus once it returns to its resting state following an excitation. |
True or False: Can the T wave be either elevated or depressed in the presence of current or previous cardiac ischemia? | True |
What is represented by the P-QRS-T pattern? | One complete cardiac cycle |
Which lead should be placed on the left arm? | Lead I (+) |