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 C
Explanation
Ventricular gallop is another name for the S3 sound, which is a low-pitched sound heard at the end of diastole, just after the S2 sound. It is caused by the rapid filling of the ventricles and the vibration of the ventricular walls.
Closure of the pulmonic valve is one of the components of the S2 sound, which is a high-pitched sound heard at the end of the systole, just before the S1 sound. It is caused by the closure of the semilunar valves (pulmonic and aortic).
Closure of the mitral valve is one of the components of the S1 sound, which is a high-pitched sound heard at the beginning of systole, just after the S2 sound. It is caused by the closure of the atrioventricular valves (mitral and tricuspid).
d. Atrial gallop is another name for the S4 sound, which is a low-pitched sound heard at the end of diastole, just before the S1 sound. It is caused by atrial contraction and increased resistance to ventricular filling.
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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