Chapter 8/Basic Cardiac Rhythm Interpretation study guide 2024

1. When evaluating a client's laboratory results, the nurse is particularly concerned that which electrolyte imbalances would cause rhythm disturbances? (Select all that apply.) 1. Hyperkalemia 2. Hypokalemia 3. Hypernatremia 4. Hyponatremia 5. Hypermagnesemia - ...Answer: 1, 2, 3, 4 Rationale: 1. Since potassium is involved in depolarization and repolarization of the cardiac cell, imbalances will affect cardiac rhythm. 2. Since potassium is involved in depolarization and repolarization of the cardiac cell, imbalances will affect cardiac rhythm. 3. Since sodium is involved in depolarization and repolarization of the cardiac cell, imbalances will affect cardiac rhythm. 4. Since sodium is involved in depolarization and repolarization of the cardiac cell, imbalances will affect cardiac rhythm. 5. While magnesium does affect cardiac muscle rhythm, it is not as implicated as potassium and sodium. Hypermagnesemia is likely to result in a prolonged PR interval, widened QRS complexes, bradycardia, and tall, peaked T waves. 2. The nurse should intervene if which finding is observed on the cardiac monitor? (Select all that apply.) 1. R-R intervals are regular. 2. PR interval is 0.30 seconds. 3. P waves precede QRS complexes. 4. QRS interval is 0.20 seconds. 5. The ST segment is on the isoelectric line. - ...Answer: 2, 4 Rationale: 1. R-R intervals should be regular. 2. The PR interval should be 0.12 to 0.20 seconds. Prolongation indicates heart block. 3. There should be a P wave before each QRS segment. 4. The QRS interval should be 0.10 seconds or less. Prolongation indicates bundle branch block. 5. The ST segment should be on the isoelectric line. 3. When interpreting an ECG, the nurse notes the following: HR 75 bpm, R-R intervals are regular, each P wave looks alike, the PR interval is 0.15 seconds, each P wave is followed by a QRS, the QRS complex is 0.10 seconds, and the QT interval is half the R-R interval. How should the nurse interpret this rhythm? 1. A dysrhythmia 2. Sinus bradycardia 3. Normal sinus rhythm 4. Heart block - ...Answer: 3 Rationale: 1. The R-R intervals are regular and the other components of the complex are within normal limits, so this is not a dysrhythmia. 2. Sinus bradycardia has a rate of less than 60 bpm. 3. All components of this rhythm are within normal parameters and the rhythm is regular. This is a sinus rhythm. 4. The PR interval is within normal limits and there is a P wave present for each QRS, so heart block does not exist. 4. A client's morning potassium is 2.0 mEq/L. As a result, the nurse identifies which nursing diagnosis as having the greatest priority? 1. Alteration in fluid volume (deficit) 2. Altered nutrition (less than) body requirements 3. Decreased cardiac output 4. Altered urinary elimination - .Answer: 3..Rationale: 1. Alteration in fluid volume may result in low potassium, but this is not the most critical diagnosis. 2. Poor nutrition may result in low potassium, but this is not the most critical diagnosis. 3. A very low potassium is likely to result in ventricular rhythm instability, which will result in decreased cardiac output. 4. Altered urinary elimination is not the priority with this client. 5. A client has sinus bradycardia. The nurse would intervene if the client developed with which findings? (Select all that apply.) 1. Dizziness 2. Hypotension 3. Angina 4. Fever 5. A heart rate of 60 - ...Answer: 1, 2, 3 Rationale: 1. Dizziness is a sign that cerebral perfusion is inadequate. The nurse would intervene. 2. Hypotension is a sign that cerebral perfusion is inadequate and requires intervention. 3. Angina is a sign that the myocardium is not receiving adequate oxygen. The nurse would intervene. 4. Fever is not a likely consequence of sinus bradycardia. 5. If the client's heart rate reaches 60, he is no longer bradycardic.