A nurse is interpreting the ECG strip of a client who has bradycardia. Which of the following cardiac components should the nurse identify as the role of the P wave?
Slow repolarization of ventricular Purkinje fibers
Atrial depolarization
Early ventricular repolarization
Ventricular depolarization
The Correct Answer is B
The P wave is the first wave on the ECG strip and represents the electrical activity of the atria. It reflects the depolarization of the atrial myocardium, which is the process of changing the electrical charge of the cardiac cells from negative to positive, triggering a contraction. The P wave precedes the QRS complex, which represents ventricular depolarization, and the T wave, which represents ventricular repolarization.
The other options are not correct because:
a. Slow repolarization of ventricular Purkinje fibers. This statement is incorrect because it describes the U wave, which is a small and sometimes invisible wave that follows the T wave on the ECG strip. It reflects the repolarization of the ventricular Purkinje fibers, which are specialized cardiac cells that conduct electrical impulses to the ventricles. The U wave is more prominent in conditions that cause hypokalemia, such as diuretic use or vomiting.
c. Early ventricular repolarization. This statement is incorrect because it describes the ST segment, which is the flat line between the QRS complex and the T wave on the ECG strip. It reflects the early phase of ventricular repolarization, which is the process of restoring the electrical charge of the cardiac cells to negative after a contraction. The ST segment can be elevated or depressed in conditions that cause myocardial ischemia or injury, such as angina or myocardial infarction.
d. Ventricular depolarization. This statement is incorrect because it describes the QRS complex, which is the largest and most visible wave on the ECG strip. It reflects the depolarization of the ventricular myocardium, which triggers a ventricular contraction. The QRS complex follows the P wave and precedes the T wave on the ECG strip.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Planning to slow down if tired the day after exercising is a statement that indicates the client understands the importance of pacing activities and avoiding overexertion, which can worsen heart failure symptoms.
a. "I should use naproxen to manage discomfort." is not correct, as naproxen is a nonsteroidal anti-inflammatory drug (NSAID) that can cause fluid retention, increase blood pressure, and worsen heart failure. The client should avoid NSAIDs and use other analgesics, such as acetaminophen, unless contraindicated.
c. "I will read food labels and limit my sodium to 4 grams per day." is not appropriate, as 4 grams of sodium per day is too high for a client who has congestive heart failure. The client should limit sodium intake to 2 grams or less per day, as sodium can cause fluid retention and increase the workload of the heart.
d. "I will take my diuretic before sleep and drink fluids during the day." is not advisable, as taking a diuretic before sleep can cause nocturia and disrupt the sleep cycle, which can affect the quality of life and cardiac function. The
Correct Answer is ["24"]
Explanation
To calculate the infusion rate, use the formula:
(rate in mL/hr) = (desired dose in units/hr) / (available dose in units/mL)
In this case, the desired dose is 1,200 units/hr and the available dose is 25,000 units / 500 mL = 50 units/mL. Therefore,
(rate in mL/hr) = (1,200 units/hr) / (50 units/mL) = 24 mL/hr
Round the answer to the nearest tenth/whole number and use a leading zero if it applies. Do not use a trailing zero because it could be misread as a decimal point. Therefore, the nurse should set the IV pump to deliver 24 mL/hr.
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