MCQs on ECG

ECG or Electrocardiograph is a test that is used to assess the Muscular and Electrical functionalities of the Heart. It is a painless test that can be conducted in a few minutes and results can also be read instantly. An Electrocardiograph is basically a graph of voltage plotted against the time of electrical activity of the heart.

The electrical activity of the heart - The Electrical System is the power source that makes the working of the heart possible in a Nutshell. The electrical impulses trigger the heartbeat that travels down a pathway through the heart. These pathways are conduction pathways and they are responsible for causing ventricles of the heart to contract and pump out blood. The human heart has a natural pacemaker that produces these electrical impulses all by itself. These electrical impulses generate an electrical current that spreads over our body. An electrocardiogram measures these currents in the form of wave graphs on paper.

The electrodes of the electrocardiogram are placed on the skin to note the normal working conditions of the heart. These electrodes detect the electrical impulses occurring during each heartbeat. The impulses are picked up from the changes in an electrical path on the skin. These changes arise from the heart muscles and the electrophysiologic patterns of depolarizing.

Let’s have a look at some solved Multiple-choice questions on ECG

MCQs on Electrocardiography or ECG

1. Who developed an Electrocardiogram?

1. Wilhelm His

2. Steward

3. Hubert Mann

4. Willem Einthoven

Answer: (d)

2. In the case of a normal Heartbeat, Depolarization stimulus arises in which of the following?

1. Epicardium

2. Sinoatrial Node (SA node)

3. Atrioventricular Node (AV node)

4. His bundle

Answer: (b)

3. What does the P wave represent?

1. Depolarization of the atria

2. Depolarization of the ventricles

3. Represents the repolarization of the ventricles

4. Depolarization of the atria and ventricles

Answer: (a)

4. Which of these cannot be detected by an Electrocardiogram?

1. The rate and rhythm of Heartbeats

2. The size and position of the Heart chambers

3. The function of implanted Pacemakers

4. Presence of asymptomatic blockages in the atria of the Heart

Answer: (d)

5. Which of the following indicates Ventricular Muscle Depolarization?

1. P wave

2. QRS complex

3. T wave

4. PR interval

Answer: (b)

6. What does the T wave represent in an ECG?

1. Atrial diastole

2. Atrial systole

3. Ventricular diastole

4. Joint diastole

Answer: (c)

7. What does the Depolarization of Ventricles initiate?

1. Atrial diastole

2. Atrial systole

3. Ventricular systole

4. Joint diastole

Answer: (c)

8. Counting the number of QRS complexes, which of the following can be interpreted?

1. Rate of heartbeat

2. Rate of breathing

3. Cardiac output

4. Stroke volume

Answer: (a)

9. What do Depolarization and Repolarization initiate in different chambers of the Heart?

1. Contraction and relaxation

2. Relaxation and contraction

3. Thickening and thinning

4. Contraction and thickening

Answer: (a)

10. Which of the following waves of ECG represent Repolarization?

1. P wave

2. QRS complex

3. RS wave

4. T wave

Answer: (d)

11. In a single circulation the Heart Pumps?

1. Oxygenated blood

2. Deoxygenated blood

3. Mixed blood

4. Only blood nutrients

Answer: (b)

12. The Depolarization Stimulus for the normal Heartbeat originates in the

1.  Epicardium

2.  His-bundle areas

3. Atrioventricular (AV) nodal

4.  Sinoatrial (SA) node

Answer: (d)

13. A shortened PR interval, slurring (called a delta wave) of the initial QRS deflection, and prolonged QRS duration are characteristics of

1. Wolff-Parkinson-White (WPW) syndrome

2. B. Atrial tachycardia

3. C.  Left bundle branch block

4. D. Myocardial ischemia

Answer: (a)

14. The classic ECG changes in Myocardial Infarction (MI. are

1. T-wave inversion

2. ST-segment elevation

3. Development of an abnormal Q wave

4. All of the above

Answer: (d)

15. ECG depicts the Depolarisation and Repolarisation processes during the Cardiac Cycle. In the ECG of a normal healthy individual one of the following waves is not represented, which one is that?

1. Depolarization of atria

2. Repolarization of atria

3. Depolarization of ventricles

4. Repolarization of ventricles

Answer: (b)

16. Which of the following correctly explains a phase/ event in cardiac cycle in a standard Electrocardiogram?

1. QRS complex indicates atrial contraction.

2. QRS complex indicates ventricular contraction.

3. Time between S and T represents atrial systole.

4. P-wave indicates beginning of ventricular contraction.

Answer: (b)

17. In a normal individual, the heart rate can be determined by the ___________ in an ECG

1. Interval between two QRS complexes

2. Number of P waves

3. Interval between the P and T waves

4. Number of T waves

Answer: (a)

18. This is the classic ECG change in MI (Myocardial Infarction.

1.  ST-segment elevation

2. T-wave inversion

3. Development of an abnormal Q wave

4. All of these

Answer: (d)

19. In which of these conditions can widen QRS and Tall-tented T waves be observed

1. Hyponatremia

2. Hyperkalemia

3. Hyperglycemia

4. Hyperphosphatemia

Answer: (b)

20. A particular ECG change observed in Hypokalemia is

1. ST-segment elevation

2. U wave, which is a position deflection after the T wave

3. Tall peaked T waves

4. Widening of the QRS complex and increased amplitude

Answer: (b)

21. ECG identified by the PR interval tends to become longer with every succeeding ECG complex until there is a P wave not followed by a QRS is observed in

1. Third-Degree Atrioventricular Block

2. Second-Degree Atrioventricular Block, Type II

3. Second-Degree Atrioventricular Block, Type I

4. First-Degree Atrioventricular Block, Type II

Answer: (c)

22. The waves which represent the excitation of the atria are,

1.  P-wave

2. QRS complex

3.  T-wave

4.  ST-segment

Answer: (a)

23. The depolarization of the ventricles is represented in,

1. P-wave

2. T-wave

3. QRS complex

4. PQ interval

Answer: (c)

24. The heartbeat of a person can be determined by which of the following waves?

1. P-wave

2. QRS complex

3. ST-segment

4. PQ interval

Answer: (b)

25. The enlargement of auricles is represented by,

1. Enlargement of P-wave

2. Enlargement of QR segment

3. Depression of ST segment

4. Elevation of ST segment

Answer: (a)

26. Depression of the ST segment depicts, which of the following?

1. Ischemia

2. Hypokalemia

3. Myocardial infarction

4. Acute heart attack

Answer: (a)

27. The longest refractory period is found in which of the following muscles?

1. Skeletal muscles

2. Smooth muscles

3. Cardiac muscles

4. Facial muscles

Answer: (c)

28. The full form of ECG is

1. Electricity cardiac group

2. Electrocardio group

3. Electrocardium granules

4. Electrocardiogram

Answer: (d)

29.  AV block refers to

1. Impulse not reaching SA node

2. Impulse not reaching the AV node

3. Impulse not reaching Purkinje fibers

4. Impulse not generating in the heart

Answer: (b)

30. The major symptom of heart failure is

1. Lung congestion

2. Vomiting

3. Yellowing of eyes

4. Pain in the chest

Answer: (a)

31. The full form of CAD is

1. Coronary artery disease

2. Carotid artery disorder

3. Carotid artery disease

4. Coronary angina disorder

Answer: (a)

32. Immediately after the QRS wave, which of the phases of the cardiac cycle follows?

1. Isovolumic relaxation

2. Ventricular ejection

3. Atrial systole

4. Isovolumic contraction

Answer: (d)

33. The positive electrode when recording lead aVL on an EKG is

1. left arm

2. left leg

3. right leg

4. left arm + left leg

Answer: (a)

34. From an ECG of a horse, which of the following cannot be determined?

1. Heart rhythm

2. Heart rate

3. Ventricular enlargement presence 

4. The duration of the P-R interval

Answer: (c)

35. Leads V3 and V4 represent which of the following views of the heart?

1. Septal

2. Inferior

3. Anterior

4. Lateral

Answer: (c)

36. A normal PR interval duration ranges between

1. 0.04 - 0.12 seconds (small squares of 1-3)

2. 0.12 - 0.2 seconds (small squares of 3-5)

3. 0.04 - 0.08 seconds (small squares of 1-2)

4. 0.08 - 0.12 seconds (small squares of 2-3)

Answer: (b)

37. If leads II, III, and aVF, note the ST-elevation, what would it suggest?

1. An inferior myocardial infarction

2. A posterior myocardial infarction

3. A septal myocardial infarction

4. An anterior myocardial infarction

Answer: (a)

38. Left axis deviation is caused due to

1. Defects of the conduction system

2. Atrial septal defects

3. Right ventricular hypertrophy

4. Left ventricular hypertrophy

Answer: (a)

39. QRS complex's normal duration is

1. 0.04 seconds (1 small square)

2. 0.08 seconds (2 small squares)

3. 0.16 seconds (4 small squares)

4. 0.12 seconds (3 small squares)

Answer: (d)