A nurse is interpreting a client's ECG strip. Which of the following components of the ECG should the nurse examine to determine the time it takes for ventricular depolarization and repolarization?
QRS complex
QT interval
ST segment
PR interval
The Correct Answer is B
B. The QT interval represents ventricular depolarization and repolarization. It starts at the beginning of the QRS complex and ends at the end of the T wave. The QT interval reflects the total time it takes for both ventricular depolarization and repolarization to occur. Prolongation of the QT interval can be associated with an increased risk of arrhythmias, including torsades de pointes.
A. The QRS complex represents ventricular depolarization, which is the electrical activation of the ventricles. The duration of the QRS complex provides information about the time it takes for ventricular depolarization to occur. A prolonged QRS complex can indicate abnormalities in ventricular conduction, such as bundle branch blocks or ventricular hypertrophy.
C. The ST segment represents the early part of ventricular repolarization. It starts at the end of the QRS complex and ends at the beginning of the T wave. Changes in the ST segment, such as elevation or depression, can indicate myocardial ischemia or injury.
D. The PR interval represents the time it takes for the electrical impulse to travel from the atria to the ventricles. It includes atrial depolarization, atrial contraction, and the delay at the atrioventricular node. The PR interval does not specifically provide information about ventricular depolarization and repolarization.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
A. A heart murmur typically indicates turbulent blood flow through a heart valve. This turbulence can occur due to various reasons, such as valve stenosis (narrowing), regurgitation (leakage), or structural abnormalities of the valves. The turbulent flow produces audible sounds that can be heard with a stethoscope during cardiac auscultation.
B. A heart murmur is not caused by blood entering an inflexible chamber. Instead, it is caused by turbulent blood flow through the heart valves. The sound produced by this turbulent flow may vary depending on the underlying pathology of the valve.
C. While heart murmurs can be described based on their characteristics (such as high-pitched or low- pitched), the presence of a heart murmur does not necessarily indicate a narrow valve. Murmurs can occur due to various valve abnormalities, including stenosis (narrowing) or regurgitation (leakage). The pitch and quality of the murmur may vary depending on the underlying pathology and the location of the abnormality.
D. A heart murmur is not typically associated with inflammation around the heart. While inflammation of the heart (such as myocarditis or pericarditis) can cause symptoms and abnormal sounds, these conditions would not be described specifically as a "heart murmur."
Correct Answer is A
Explanation
A. The insertion of a pulmonary artery catheter can help in assessing hemodynamic parameters and distinguishing between these two conditions. It provides direct measurement of pulmonary artery pressures, which can be elevated in the case of heart failure.
B. A ventilation-perfusion (V/Q) scan is used to evaluate ventilation and perfusion in the lungs. While it can help identify areas of ventilation-perfusion mismatch, it may not be the most appropriate initial test for distinguishing between ARDS and pulmonary edema.
C. Drawing blood for arterial blood gases is also a critical step as it helps in assessing the severity of hypoxemia and respiratory failure.
D. A chest x-ray can show the presence of bilateral opacities, which are indicative of ARDS when cardiac failure or fluid overload is not the primary cause. However, transthoracic echocardiography (TTE) is often performed to seek evidence of cardiac dysfunction when cardiogenic pulmonary edema cannot be excluded by clinical evaluation, laboratory findings, or imaging.
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