Which of the following ECG rhythm interval measures is considered abnormal?
QTc interval 0.33 to 0.47 seconds
QT interval that varies with HR
QRS interval <0.12 seconds
PR interval 0.12 to 0.24 seconds
The Correct Answer is A
The QTc (corrected QT) interval is a measure of the time it takes for the ventricles to depolarize and repolarize during a cardiac cycle. It is corrected for heart rate (HR) to account for variations in the cardiac cycle length.
The normal range for the QTc interval varies depending on the calculation method used but generally falls within 0.36 to 0.44 seconds. In the given options, the range of 0.33 to 0.47 seconds for the QTc interval is wider than the normal range, suggesting a prolonged QTc interval, which can be indicative of a potential risk for arrhythmias, including ventricular tachycardia and torsades de pointes.
B. QT interval that varies with HR in (option B) is normal because The QT interval alone can vary with heart rate, and this is considered a normal physiological adaptation.
C. QRS interval <0.12 seconds in (option C) is normal because The QRS interval represents the time it takes for ventricular depolarization and is normally less than 0.12 seconds.
D. PR interval 0.12 to 0.24 seconds in (option D) is normal because The PR interval represents the time it takes for atrial depolarization and conduction through the AV node. The normal range is typically 0.12 to 0.20 seconds.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
Heart rate: 72 beats per minute Stroke volume: 90 mL/contraction
Cardiac output = Heart rate × Stroke volume
Cardiac output = 72 beats/minute × 90 mL/contraction
To simplify the calculation, you can convert the units:
72 beats/minute × 90 mL/contraction = (72 × 90) beats/minute × mL/contraction
Now, perform the multiplication:
72 × 90 = 6,480
Therefore, the cardiac output is 6,480 mL per minute.
The correct answer is:
C. 6,480 mL
Correct Answer is ["9000"]
Explanation
4 mL × body weight in kg × percentage of burn = total fluid volume for the first 24 hours Then, divide the total fluid volume by 2 to determine the fluid volume for the first 8 hours.
In this case, the patient weighs 90 kg and has a 50% burn injury.
4 mL × 90 kg × 50% = 18,000 mL (total fluid volume for 24 hours)
18,000 mL / 2 = 9,000 mL (fluid volume for the first 8 hours)
Therefore, the nurse would infuse the intravenous fluid resuscitation at a rate of 9,000 mL over the first 8 hours.
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