WorksheetsECG Leads
Total questions: 16
Worksheet time: 16mins
Which one of the following descriptions or statements about an electrocardio-
gram (ECG) is NOT correct?
A. It is a record of the voltage changes (as measured at the body surface) due
to the depolarisation of the muscle cells of the heart as it beats.
B. The potentials measured by the ECG electrodes are combined in various
ways to give 12 different ECGs.
C. The ECG consists of the electrical events that follow the depolarisation of
ventricles (PQR section), the depolarisation of atria (the S section) and the
repolarisation of the ventricles (the T section).
D. The value of the potential difference called “limb lead II” varies with time
to produce the familiar ECG trace – a graph of voltage vs time.
Which of the following does limb lead II of a typical electrocardiogram
represent?
A. A graph of the variation of voltage produced by the heart against time.
B. The voltage at right arm (RA) plus the voltage at left leg (LL).
C. The electrical events that precede the contraction of the ventricles.
D. The projection of the electric dipole vector of the heart on the line from left
arm (LA) to right arm (RA).
What view of the heart do leads V1 and V2 represent?
A
Septal
B
Lateral
C
Anterior
D
Inferior
What would it suggest if lead I became more positive than lead II and lead III ?
A
Left axis deviation
B
Right axis deviation
Which artery is most likely to be affected in the context of ST elevation being present in leads V3 and V4?
A
Left circumflex coronary artery
B
Left anterior descending coronary artery
C
Right coronary artery
D
All of the above
If ST-elevation was noted in leads II, III and aVF, what would it suggest?
A
A septal myocardial infarction
B
A posterior myocardial infarction
C
An anterior myocardial infarction
D
An inferior myocardial infarction
What is the duration of a normal PR-interval?
A
0.04 - 0.12 seconds (1-3 small squares)
B
0.08 - 0.12 seconds (2-3 small squares)
C
0.12 - 0.2 seconds (3-5 small squares)
D
0.04 - 0.08 seconds (1-2 small squares
What view of the heart do leads I, aVL, V5 and V6 represent?
A
Septal
B
Anterior
C
Lateral
D
Inferior
What view of the heart do leads II, III and aVF represent?
A
Septal
B
Inferior
C
Lateral
D
Anterior
What view of the heart do leads V3 and V4 represent?
A
Septal
B
Inferior
C
Lateral
D
Anterior
An ECG is performed and reveals a progressively increasing PR interval and dropping of QRS complexes at regular intervals. Which of the following is the most likely diagnosis?
A
Hyperkalaemia
B
Second-degree heart block (Mobitz type 1)
C
Second-degree heart block (Mobitz type 2)
D
First-degree heart block
A patient is noted to have an abnormally shortened PR-interval on their ECG. Which of the following is the most likely cause?
A
Atrioventricular nodal fibrosis
B
Wolff-Parkinson-White (WPW) syndrome
C
Left bundle branch block
D
Right bundle branch block
What is the most common cause of left axis deviation?
A
Left ventricular hypertrophy
B
Right ventricular hypertrophy
C
Defects of the conduction system
D
Atrial septal defects
An ECG reveals an absence of P-waves and an irregular rhythm. Which of the following is the most likely diagnosis?
A
2nd-degree heart block
B
1st-degree heart block
C
Atrial fibrillation
D
Ventricular tachycardia
What is the normal duration of a QRS complex?
0.04 seconds (1 small square)
0.16 seconds (4 small squares)
0.12 seconds (3 small squares)
0.08 seconds (2 small squares)
Which of the following is a common cause of right axis deviation?
Right ventricular hypertrophy
Left ventricular hypertrophy
Ventricular septal defect
Atrial septal defect
