Ati lpn mental health exam
Ati lpn mental health exam ( 36 Questions)
A nurse is helping care for a client admitted to the telemetry unit with chest pain, dyspnea, and diaphoresis. Which ECG finding indicates an acute myocardial infarction?
The PR interval, which is the time from the onset of atrial depolarization (beginning of the P wave) to the onset of ventricular depolarization (beginning of the QRS complex), normally ranges from 0.12 to 0.20 seconds. A PR interval of 0.15 second is within the normal range and does not indicate an acute myocardial infarction.
The QT interval represents the total time for ventricular depolarization and repolarization. The normal QT interval varies based on heart rate and gender but is typically less than half of the R-R interval in a normal heart rhythm. Therefore, a QT interval equal to the R-R interval is abnormally prolonged, which may suggest other conditions but is not a specific indicator of acute myocardial infarction.
The QRS complex reflects ventricular depolarization and normally ranges from 0.06 to 0.10 seconds. A QRS interval of 0.08 second is within the normal range and does not suggest an acute myocardial infarction.
ST segment elevation is a critical finding in the diagnosis of acute myocardial infarction. The ST segment should be at the isoelectric line; elevation above this line is indicative of myocardial injury and is a key diagnostic criterion for ST-elevation myocardial infarction (STEMI). An elevated ST segment is often seen in the early stages of an acute myocardial infarction and requires immediate medical attention.
Choice A reason: The PR interval, which is the time from the onset of atrial depolarization (beginning of the P wave) to the onset of ventricular depolarization (beginning of the QRS complex), normally ranges from 0.12 to 0.20 seconds. A PR interval of 0.15 second is within the normal range and does not indicate an acute myocardial infarction.
Choice B reason: The QT interval represents the total time for ventricular depolarization and repolarization. The normal QT interval varies based on heart rate and gender but is typically less than half of the R-R interval in a normal heart rhythm. Therefore, a QT interval equal to the R-R interval is abnormally prolonged, which may suggest other conditions but is not a specific indicator of acute myocardial infarction.
Choice C reason: The QRS complex reflects ventricular depolarization and normally ranges from 0.06 to 0.10 seconds. A QRS interval of 0.08 second is within the normal range and does not suggest an acute myocardial infarction.
Choice D reason: ST segment elevation is a critical finding in the diagnosis of acute myocardial infarction. The ST segment should be at the isoelectric line; elevation above this line is indicative of myocardial injury and is a key diagnostic criterion for ST-elevation myocardial infarction (STEMI). An elevated ST segment is often seen in the early stages of an acute myocardial infarction and requires immediate medical attention.