Deck 9: ST Segments, T-Waves, QT Intervals, and U-Waves

Question 1

The ___________ represents the end of ventricular depolarization and beginning of ventricular repolarization.

A) T wave
B) U wave
C) QT interval
D) ST segment

Answer 1

ST segment

Question 2

The ST segment begins at the ________.

A) upslope of the S wave
B) J point
C) M point
D) point where the R and S wave meet

Answer 2

J point

Question 3

The ST segment is best described as a/an:

A) large, upright, round, asymmetrical waveform.
B) isoelectric line.
C) interval that extends from the beginning of the Q wave to the end of the T wave.
D) small, upright, round, asymmetrical waveform.

Answer 3

isoelectric line.

Question 4

The duration of the ST segment is normally ________ seconds.

A) 0.08 to 0.12
B) 0.06 to 0.10
C) 0.08 to 0.10
D) 0.08 to 0.14

Question 5

Which of the following is "most commonly" assessed with the ST segment?

A) Elevation
B) Depression
C) Duration
D) a and b

Question 6

ST segment changes are identified by:

A) measuring from the beginning of the ST segment to its end.
B) comparing the ST segment with the PR segment.
C) comparing the ST segment with the TP segment.
D) b & c

Question 7

For proper measurement of the ST segment, we use a point ____ seconds after the J point to identify changes.

A) 0.02
B) 0.04
C) 0.06
D) 0.08

Question 8

An ST segment is considered elevated if it is:

A) 0.5 to 1.0 above the baseline.
B) more than 1.0 mm above the baseline.
C) more than 1.0 mm below the baseline.
D) more than 5.0 mm above the baseline.

Question 9

An ST segment is considered depressed if it is:

A) 0.5 to 1.0 above the baseline.
B) more than 1.0 mm above the baseline.
C) more than 1.0 mm below the baseline.
D) more than 5.0 mm above the baseline.

Question 10

ST segment elevation suggests:

A) Myocardial ischemia
B) Myocardial injury
C) Pericarditis
D) b & c

Question 11

ST segment depression suggests:

A) Myocardial ischemia
B) Myocardial injury
C) Right and left ventricular hypertrophy
D) a & c

Question 12

The ___________ represents ventricular repolarization.

A) T wave
B) U wave
C) QT interval
D) ST segment

Question 13

The T wave begins at the ________.

A) upslope of the S wave
B) J point
C) M point
D) point where the ST segment ends

Question 14

The T wave is best described as a/an:

A) large, upright, round, asymmetrical waveform.
B) isoelectric line.
C) interval that extends from the beginning of the Q wave to the end of the T wave.
D) small, upright, round, asymmetrical waveform.

Question 15

The height of the T wave is normally no greater than ________ mm in the limb leads.

A) 2
B) 5
C) 10
D) 15

Question 16

The height of the T wave is normally no greater than ________ mm in the precordial leads.

A) 2
B) 5
C) 10
D) 15

Question 17

T waves are normally positive in leads:

A) I, II, and V2 to V6
B) aVR, aVF, aVL
C) I, II, and aVR
D) aVR, V1 and V2

Question 18

The T wave is normal oriented in the ________ direction as the preceding QRS complex.

A) opposite
B) same

Question 19

Which of the following is commonly assessed with the T wave?

A) Configuration
B) Amplitude
C) Deflection
D) All of these

Question 20

Tall or peaked T waves, also known as tented T waves, are seen in:

A) subarachnoid hemorrhage.
B) myocardial ischemia and hyperkalemia.
C) impulses that arise from the ventricles.
D) Digitalis toxicity and beta blocker use.

Question 21

The QT interval:

A) represents the time needed for ventricular repolarization.
B) is prolonged when ventricular repolarization is accelerated.
C) extends from the beginning of the P wave to the end of the T wave.
D) is usually between 0.36 and 0.44 seconds in duration.

Question 22

A prolonged QT interval:

A) indicates prolonged ventricular repolarization.
B) can be caused by hypercalcemia or digoxin toxicity.
C) is defined as one having a duration of greater than 0.50 seconds.
D) can predispose the patient to dysrhythmias such as sinus tachycardia.

Question 23

The U wave:

A) deflects opposite of its associated QRS complex
B) is always present
C) follows the T wave
D) is larger than the T wave

Question 24

Prominent U waves are seen in:

A) hypokalemia.
B) myocardial infarction.
C) digitalis toxicity.
D) All of these

Question 25

The J point is not always easy to identify when assessing the ST segment. Sometimes you can identify it by looking for a small notch, slope, or other movement that suggests an alteration of electrical flow.

Question 26

To measure the T wave, identify its starting and ending point, then move to the center of the waveform. Next, count the number of small boxes between the isoelectric line and the top of the waveform.

Question 27

T waves with bumps may be seen when P waves are buried in the T waves.

Question 28

T waves seen with impulses that arise from the ventricles take the same direction as their associated QRS complexes.

Question 29

To measure the QT interval, first locate the isoelectric line immediately preceding the Q wave (or R wave if there is no Q wave). Next, locate the end of the T wave. Count the number of boxes in between these two points.