menu_book
Dynoble Books
Login
Chapter 7 Test — The QRS Complex: Width, Voltage and Morphology
18 questions · 18 min · +4 / -1
--:--
Question
1
of 18
0
/18 answered
Question 1
Question 1
Mark for review
The QRS complex on the surface ECG is produced by:
A.
Ventricular repolarisation
B.
Atrial depolarisation
C.
Conduction through the AV node
D.
Ventricular depolarisation
Clear my answer
Question 2
Question 2
Mark for review
The figure shows the four sequential phases of ventricular depolarisation and the QRS complex they build up in lead II. Panel
A
represents the first phase. Which event does it depict?
A.
Depolarisation of the basal regions of both ventricles
B.
Depolarisation of the interventricular septum from left to right
C.
Repolarisation of the subepicardial myocardium
D.
Depolarisation of the bulk of the left ventricular free wall
Clear my answer
Question 3
Question 3
Mark for review
A 58-year-old man presents with palpitations and a regular broad-complex tachycardia. Above which QRS duration is a complex considered abnormally widened?
A.
> 0.06 seconds
B.
> 0.08 seconds
C.
> 0.10 seconds
D.
> 0.12 seconds
Clear my answer
Question 4
Question 4
Mark for review
Which statement correctly describes the criteria for
low QRS voltage
on a standard 12-lead ECG?
A.
QRS <15 mm in the precordial leads alone
B.
QRS <5 mm in any one limb lead is sufficient
C.
QRS <5 mm in all limb leads AND <10 mm in all precordial leads
D.
QRS <10 mm in all limb leads OR <5 mm in all precordial leads
Clear my answer
Question 5
Question 5
Mark for review
The rhythm strip shown is a rapid, regular tachycardia in which every QRS complex measures about 90 ms. What does the
narrow
QRS tell you about this rhythm?
A.
It has originated in ventricular muscle below the bundle branches
B.
It is conducted over an accessory pathway that bypasses the AV node
C.
It originated above the ventricles and reached them via the His-Purkinje system
D.
It indicates a bundle branch block on the left side of the heart
Clear my answer
Question 6
Question 6
Mark for review
A wide QRS complex (≥0.12 seconds) may be seen in all of the following EXCEPT:
A.
Hyperkalaemia
B.
Wolff-Parkinson-White syndrome
C.
Ventricular tachycardia
D.
Left anterior fascicular block
Clear my answer
Question 7
Question 7
Mark for review
A 20-year-old asymptomatic athlete has a routine ECG showing a small rSr' pattern in lead V1. The total QRS duration is 90 ms and the rest of the ECG is normal. What is the correct interpretation?
A.
Complete right bundle branch block
B.
Brugada syndrome requiring electrophysiology referral
C.
A normal variant requiring no investigation
D.
Incomplete left bundle branch block
Clear my answer
Question 8
Question 8
Mark for review
The figure compares QRS morphology in V1 and V6 in normal conduction, RBBB and LBBB. Why does right bundle branch block produce the M-shaped ('bunny ear') complex in V1?
A.
The right ventricle depolarises late by slow cell-to-cell muscle spread after the left ventricle
B.
The right ventricle is hypertrophied and generates a larger initial vector
C.
The right atrium is enlarged and its P wave merges with the QRS
D.
An accessory pathway pre-excites the right ventricle before the AV node conducts
Clear my answer
Question 9
Question 9
Mark for review
The 12-lead ECG shown demonstrates uniformly small QRS complexes in both the limb and the precordial leads. This finding is classically produced by:
A.
Pulmonary embolism
B.
Pericardial effusion
C.
Cor pulmonale
D.
Infective endocarditis
Clear my answer
Question 10
Question 10
Mark for review
All of the following typically cause LOW QRS voltage EXCEPT:
A.
Cardiac amyloidosis
B.
A thin chest wall in a young adult
C.
Obesity
D.
Chronic obstructive pulmonary disease with hyperinflation
Clear my answer
Question 11
Question 11
Mark for review
Panel B of the figure shows the precordial pattern of right ventricular hypertrophy: a dominant tall R wave in V1–V3 with deep S waves in V5–V6. This pattern is most characteristically seen in:
A.
Pulmonary hypertension and cor pulmonale
B.
Systemic hypertension
C.
Isolated mitral regurgitation
D.
Aortic stenosis
Clear my answer
Question 12
Question 12
Mark for review
The figure shows leads II, III and aVF, with arrows marking the initial negative deflections. Which finding would make these Q waves
pathological
rather than normal?
A.
Width >40 ms or depth >25% of the R wave in the same lead
B.
Any Q wave present in leads I, aVL, V5 or V6
C.
Width >20 ms with a depth of at least 1 mm
D.
A Q wave followed by a discordant T wave
Clear my answer
Question 13
Question 13
Mark for review
Small, narrow q waves are a normal finding in leads I, aVL, V5 and V6. What produces them?
A.
Retrograde conduction of the atrial impulse into the AV node
B.
Early activation of the basal right ventricle before the left ventricle
C.
Delayed repolarisation of the subendocardial layers of the left ventricle
D.
Depolarisation of the interventricular septum from left to right
Clear my answer
Question 14
Question 14
Mark for review
A 34-year-old man has dizziness, syncope, chest pain and breathlessness. His ECG shows a shortened PR interval with widening of the QRS complex and a slurred initial upstroke. The abnormality is an accessory muscular connection between atrium and ventricle. Which pathway is this?
A.
Bachmann's bundle
B.
Tract of Wenckebach
C.
Thorel's bundle
D.
Bundle of Kent
Clear my answer
Question 15
Question 15
Mark for review
The figure contrasts normal, poor and reversed R wave progression across V1–V3. In a normal ECG, at which precordial lead does the transition zone (R wave = S wave) usually lie?
A.
V3 or V4
B.
V1 or V2
C.
V2 or V3
D.
V5 or V6
Clear my answer
Question 16
Question 16
Mark for review
An ECG shows poor R wave progression across V1–V4. Which cause should be checked
first
?
A.
Left ventricular hypertrophy
B.
Incorrect precordial lead placement
C.
Old anterior myocardial infarction
D.
Chronic obstructive pulmonary disease
Clear my answer
Question 17
Question 17
Mark for review
In a wide-complex tachycardia, the time from QRS onset to the peak of the initial R wave measures 60 ms. What does this favour?
A.
Atrial flutter with 2:1 block
B.
SVT with aberrant conduction
C.
Ventricular tachycardia
D.
Sinus tachycardia with a rate-related delta wave
Clear my answer
Question 18
Question 18
Mark for review
In standard ECG nomenclature, which statement about the components of the QRS complex is correct?
A.
The S wave is the negative deflection that precedes the R wave
B.
The Q wave is the first negative deflection of the complex
C.
The R wave is always the tallest deflection in the complex
D.
The Q wave is any negative deflection anywhere within the complex
Clear my answer
Next
Finish & see my score
All questions
Close
answered
marked for review
not answered
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Finish & see my score