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Understanding EKGs-6
Based on the book by Beasley, 2nd Edition
Question | Answer |
---|---|
What is key to learning, understanding, and interpreting dyrhythmias? | A systematic approach, which must be used each and every time a strip is analyzed. |
What are the 5 general rules for correctly identifying heart rhythms? | 1.Look at your patient! 2.Read EVERY strip from left to right 3.Apply 5-step systematic approach 4.Avoid shortcuts and assumptions 5.Ask and answer each question in the 5-step approach. 6.Master accepted limits for each dysrhythmia, apply 5-steps |
What is the 5-Step approach? | Step 1: Heart rate Step 2: Heart rhythm Step 3: P wave Step 4: PR interval Step 5: QRS complex |
What is a heart rate? | The number of electrical impulses conducted through the myocardium in 60 seconds. |
What is a parameter? | Normal boundaries for the heart rate or beats per minute |
When calculating heart rate, which chambers are measured? | Atria and Ventricles |
What is bradycardia? | Heart rate less than 60 beats per minute |
What is tachycardia? | Heart rate more than 100 beats per minute |
How is the atrial heart rate calculated? | By counting the nuberm of P waves |
How is the ventrical heart rate calculated? | By counting the number of QRS complexes |
What should you do when the atrial and ventricular heart rates are dissimilar? | Calculate both |
What is a "normal" heart rate? | 60 - 100 beats per minute |
When assessing a patient, what should be asked? | "How is the rhythm significant to the patient's clinical picture?" |
What are the two methods commonly used to determine heart rate by visual examination of an EKG strip? | 1. 6-second method 2. R-R interval method |
What is the 6-second method? | County the number of QRS complexes that occur within the 6-second interval and multiply by 10 |
What is the R-R method? | Look for QRS complexed (Specifically R wave). Divide # of R waves by 300. Example (300 / 3 = 100) |
What is step 1 in the systematic approach to EKG analysis? | Step 1: Heart rate Step |
What is step 2 in the systematic approach to EKG analysis? | Step 2: Heart rhythm |
What is heart rhythm? | The sequential beating of the heart due to electrical impulses. |
What are synonyms for rhythm? (Hint: There are 5) | Pattern, guide, model, order, and design |
What is necessary to calculate heart rhythm? | Establishing a patter of QRS complexes |
How are calculations of heart rhythms classified? | Regular or irregular |
How do you determine the classification of the heart rhythm for the ventricle? | Measure the intervals between R to R waves |
How do you determine the classification of the heart rhythm for the atrial? | Measure the intervals between P to P waves. |
How is the rhythm calculated as regular? | If the intervals vary by less than 0.06 second (or 1.5 small squares), the rhythm is regular. |
How is the rhythm calculated as irregular? | If the intervals are variable by greater than 0.06 second, the rhythm is irregular. |
On an EKG strip, what if the marks are relatively equal distances apart? | The rhythm is noted as regular. |
On an EKG strip, what if the marks vary? | The rhythm is noted as irregular. |
Describe a regularly irregular rhythm. | Irregular rhythms that occur in a pattern. |
Describe a occasionally irregular rhythm. | Intervals of only one or two R-Rs are uneven. |
Describe a irregularly irregular rhythm. | R-R intervals exhibit no similarity. |
Regardless of the rhythms, what is the most important question to remember? | "How is this rhythm clinically significant to my patient?" |
What is step 3 in the systematic approach to EKG analysis? | Is there a P wave before each QRS? Are the P waves upright and uniform? |
What do the P waves characterize? | Depolarization of the atria |
How is the P wave produced? | When the right and left atria depolarize. |
How is the depolarization of the atria produced? | When an electrical impulse spreads throughout the atria via the internodal pathways |
How is the P wave shown on the EKG strip? | The P wave is noted as the first deviation from the isoelectric line on the EKG strip and should ALWAYS by rounded and upright (positive) in chest Lead II. |
What if the P wave is NOT upright in Lead II? | You are NOT looking at a sinus rhythm (i.e., a rhythm originating in the SA node). |
What are the 5 questions that should be asked when evaluating P waves? | 1. Are P waves present? 2. Are P waves occurring regularly? 3. Is there one P wave present for each QRS complex? 4. Are P waves smooth, rounded, and upright or inverted? 5. Do ALL P waves look similar? |
How are the heart rhythms referred? | According to their points of origin |
What is Step 4 in the systematic approach to EKG analysis? | "What is the length of the PR interval?" |
What is the PR interval? | Measures the time intervals from the onset of atrial contraction to the onset of ventricular contraction or .... The time necessary for the electrical impulse to be conducted through the atria and the AV node. |
How is the PR interval measured? | From the onset (beginning) of the P wave to the onset of the Q wave of the QRS complex |
What is the normal length of the PR interval? | 0.12 - .20 second (three to five small squares). |
What takes place so the PR interval is considered within normal limits? | The PR interval should be constant across the EKG strip |
What if the PR interval is less than 0.12 second? | An indication that the usual progression of the impulse was outside the normal route |
What if the PR interval is greater than 0.20 second? | May indicate a delay in the electrical conduction pathway OR an AV block |
What are the three questions you should ask when evaluating PR intervals? | 1. Are PR intervals greater than 0.20 second? 2. Are PR intervals less than 0.12 second? 3. Are PR intervals constant across the EKG strip? |
What does the QRS complex represent? | The depolarization (or contraction) of the ventricles. |
What does the QRS complex represent WHEN they look alike? | Conduction pathways are invariable and consistent. |
What is Step 5 in the systematic approach to EKG analysis? | Do all QRS complexes look alike? What is the length of the QRS complexes? |
What does the QRS complex consist of? | Q wave + R wave + S wave |
What is the Q wave? | The first negative or downward deflection of the QRS complex, that is a small wave preceding the R wave. |
What is the R wave? | The first upward or positive deflection following the P wave. In chest Lead II, the R wave is the tallest waveform noted. |
What is the S wave? | The sharp, negative (or downward) deflection that follows the R wave. |
When functioning normally, what is the width of the QRS complex? | About 0.12 second or less (narrow). |
What does the normal QRS complex indicate? | The impulse was not formed in the ventricles and is referred to as supraventricular or "above the ventricles". |
What does a QRS complex indicate tha tis greater than 0.12 second or greater than three small squares? | The impulse is either of ventricular origin OR of supraventricular origin with conduction deviating from the norm. |
Why does the QRS complex vary slightly? | Due to individual patients and factors such as heart shape, heart size, health of the myocardium, and location & placement of electrodes. |
What is the ST segment? | Begins with the end of the QRS complex and ends with the onset of the T wave |
What is the J point? | The point where the QRS complex meets the ST segment |
What is the T wave? | Produced by ventricular repolarization or relaxation |
What may be indicated if the ST segment is elevated or depressed? | A myocardial ischemia may be indicated. |
What is a U Wave? | When they can be distinguished, they typically follow the T wave. They appear smaller than the T wave and will commonly be rounded and upright or positive in deflection. |
What is an artifact? | EKG waveforms from sources outside the heart. |
An interference seen on a monitor or an EKG strip. | Artifact |
What are the causes of an artifact? | 1. Patient movement 2. Loose or defective electrodes 3. Improper grounding 4. Faulty EKG apparatus |
True or False: Artifacts can mimic certain lethal dysrhythmias, such as ventricular fibrillation. | True |
What is important regarding artifacts? | Patient assessment is critical. If a patient is talking normally, he/she is probably NOT having a ventricular fibrillation :) |