Deck 7: QRS Complexes

Question 1

You have determined the heart rate and regularity and examined the P waves. The next logical step of analyzing an ECG rhythm is to:

A) determine the QT interval.
B) evaluate the QRS complexes.
C) examine the T waves.
D) examine the ST segments.

Answer 1

evaluate the QRS complexes.

Question 2

The normal QRS complex:

A) occurs before the PR interval.
B) has an amplitude of 5 to 15 mm.
C) consists of 2 waveforms.
D) has a duration of 0.06 to 0.10 seconds.

Answer 2

has a duration of 0.06 to 0.10 seconds.

Question 3

The Q wave is:

A) the first negative deflection following the P wave.
B) a negative deflection following the R wave.
C) normally absent.
D) sometimes upright.

Answer 3

the first negative deflection following the P wave.

Question 4

The R wave:

A) precedes the Q wave.
B) is the first positive deflection in the QRS complex.
C) is the first negative deflection that extends below the baseline.
D) is less than 25% of the amplitude of the S wave in that lead.

Question 5

The S wave in the QRS complex is:

A) the negative deflection that follows the R wave and extends below the baseline
B) sometime absent.
C) triangular shaped.
D) normally 0.04 seconds in duration and has an amplitude of 5 to 30 mm.

Question 6

In which of the following will the QRS complex have higher amplitude?

A) The elderly.
B) In women.
C) The precordial leads.
D) When there is fluid in the pericardial sac.

Question 7

A positive impulse immediately following the R wave is called:

A) S prime.
B) R prime.
C) double R prime.
D) double S prime.

Question 8

A double negative impulse immediately following the S wave is called:

A) R prime.
B) S prime.
C) double R prime.
D) double S prime.

Question 9

In leads I, II, III, aVL, aVF, and V4 to V6, the deflection of the QRS complex is characteristically:

A) upright.
B) biphasic
C) inverted
D) biphasic or inverted.

Question 10

Normal QRS complexes are those that:

A) look different.
B) are inverted.
C) are upright and narrow.
D) are wide and bizarre.

Question 11

The QRS complexes should appear normal if:

A) the rhythm is initiated from the SA node, atria, or AV junction.
B) conduction is delayed as the impulse progresses from the bundle of His, through the right and left bundle branches, and through the Purkinje network.
C) it originates from the ventricles.
D) there is a conduction delay through the ventricles.

Question 12

Very tall QRS complexes are usually caused by:

A) impulses that originate from the ventricles.
B) a rhythm that is initiated from the SA node, atria, or AV junction.
C) a delay in the movement of the electrical impulse between the right and left ventricles.
D) hypertrophy of one or both ventricles.

Question 13

Impulses that arise from the ventricles produce QRS complexes that:

A) look the same as the QRS complexes which are produced by impulses originating from the SA node.
B) are called R prime or R' waves.
C) are typically notched and biphasic.
D) appear wide and bizarre-looking.

Question 14

Wide, bizarre-looking QRS complexes that are seen with sinus rhythm may be caused by:

A) bundle branch block.
B) hypertrophy.
C) pleural effusion.
D) atrial enlargement.

Question 15

Aberrant conduction occurs when:

A) there is a blockage in one or both bundle branches.
B) an impulse arises from the ventricles and stimulates the atria in a retrograde manner.
C) early impulses are carried through one bundle branch while the other is still refractory after conducting a previous electrical impulse.
D) An impulse travels to the ventricles through an accessory pathway.

Question 16

With ventricular preexcitation there is an abnormal slurring and notching at the onset of the QRS complex. This is called a ______ wave.

A) alpha
B) QS
C) R'R
D) delta

Question 17

An escape rhythm arising from the ventricles typically has a sustained rate of _______ BPM.

A) 10 to 15
B) 20 to 40
C) 40 to 60
D) 60 to 80

Question 18

Cardiac pacemaker-induced QRS complexes are:

A) 0.12 seconds or greater in duration.
B) bizarre-looking.
C) preceded by a narrow spike.
D) All of these

Question 19

Ventricular fibrillation:

A) is seen as a flat line on the ECG tracing.
B) is caused by erratic firing of the ventricles
C) should be promptly treated with defibrillation.
D) b and c

Question 20

The QRS complex is larger than the P wave because ventricular depolarization involves a considerably larger muscle mass than atrial depolarization.

Question 21

The amplitude of the Q wave is normally less than 25% of the amplitude of the R wave in that lead.

Question 22

When referring to the QRS complex, waveforms of normal or greater than normal amplitude are denoted with a large case letter, whereas waveforms less than 5 mm amplitude are denoted with a small case letter.

Question 23

To measure the duration of a QRS complex start by finding the point where the first wave of the complex begins to deviate from the baseline and the end where the R wave joins the S wave.

Question 24

If the Q wave is absent, we measure the QRS complex from the beginning of the R wave.

Question 25

The QRS complex appears different only when the pacemaker originates from a site in the ventricles.

Question 26

Low-voltage or abnormally small QRS complexes may be seen in obese patients, hyperthyroid patients, and pleural effusion.

Question 27

Intraventricular conduction defect is a condition where conduction through the ventricles is impaired.

Question 28

Tachycardia arising from the ventricles is said to be present when there are three or more early beats (arising from the ventricles) in a row or the heart rate is sustained at a rate of between 100 and 250 beats per minute.

Question 29

Asystole is a lack of any cardiac activity in the ventricles and is seen as a flat line on the ECG tracing.