Electrocardiography
1 ECG leads displays ?
A. Instantaneous differences in electrical potential between electrodes
B. Differences in electrical potential between electrode and neutral
C. Differences in electrical potential between electrode & maximum positive charge
D. Differences in electrical potential between electrode & maximum negative charge
2 Electric currents that spread through the heart can be produced by ?
A. Cardiac pacemaker cells
B. Specialized conduction tissue
C. Heart muscle
D. All of the above
3 AV junction is constituted by ?
A. Atrioventricular (AV) node
B. AV node and His-bundle
C. AV node, His-bundle and fascicles
D. AV node, His-bundle, fascicles & Purkinje fibres
4 Ventricular repolarization is represented by ?
A. ST segment
B. T wave
C. U wave
D. ST-T-U complex
5 J point is the junction between ?
A. End of P wave & beginning of QRS complex
B. End of QRS complex & beginning of ST segment
C. End of ST segment & beginning of T wave
D. End of T wave & beginning of U wave
6 Atrial repolarization wave may become apparent in ?
A. Acute pericarditis
B. Cardiomyopathy
C. PSVT
D. Wandering pacemaker
7 Atrial repolarization wave may become apparent in ?
A. Acute rheumatic fever
B. Cardiomyopathy
C. PSVT
D. Atrial infarction
8 Rapid upstroke of the action potential that corresponds to the onset of QRS is called ?
A. Phase 0
B. Phase 1
C. Phase 2
D. Phase 3
9 Plateau of the action potential that corresponds to isoelectric ST segment is called ?
A. Phase 0
B. Phase 1
C. Phase 2
D. Phase 3
10 Which of the following prolong phase 2 of the cardiac muscle action potential and increase the QT interval ?
A. Hyperkalemia
B. Amiodarone
C. Digitalis
D. Hypercalcemia
11 The action potential of the His-Purkinje system and ventricular myocardium has ?
A. Two phases
B. Three phases
C. Four phases
D. Five phases
12 Resting membrane potential in ventricular myocardium is ?
A. Phase 1
B. Phase 2
C. Phase 3
D. Phase 4
13 Automaticity is normally observed in ?
A. Sinus node
B. Specialized fibers of His-Purkinje system
C. Some specialized atrial fibers
D. All of the above
14 Polarized resting myocardial cells carry an electric charge on their surface of about ?
A. 70 mV
B. 80 mV
C. 90 mV
D. 100 mV
15 PR interval is related to ?
A. Atrial musculature conduction
B. AV node
C. AV junction area
D. All of the above
16 Extremity ECG leads record potentials transmitted onto ?
A. Frontal plane
B. Vertical plane
C. Horizontal plane
D. Diagonal plane
17 ECG chest leads record potentials transmitted onto ?
A. Frontal plane
B. Vertical plane
C. Horizontal plane
D. Diagonal plane
18 ECG Lead V6 is placed at ?
A. Anterior axillary line
B. Midaxillary line
C. Posterior axillary line
D. Scapular line
19 Number of intercostal spaces used for placing unipolar chest leads in ECG are ?
A. 1
B. 2
C. 3
D. 4
20 In the hexaxial diagram representing frontal plane (limb or extremity) leads, 0° corresponds to which lead ?
A. Lead I
B. Lead II
C. Lead III
D. Any of the above
21 In ECG, if the mean orientation of the depolarization vector is at right angles to a given lead axis, which of the following will happen ?
A. Positive wave will be recorded
B. Negative wave will be recorded
C. Biphasic wave will be recorded
D. Flat wave will be recorded
22 ECG leads I, II, and III are called ?
A. Unipolar leads
B. Bipolar leads
C. Tripolar leads
D. Multipolar leads
23 ECG leads aVR, aVL, and aVF are called ?
A. Unipolar leads
B. Bipolar leads
C. Tripolar leads
D. Multipolar leads
24 Bipolar lead I measures the difference in potential between ?
A. Left arm-right arm voltages
B. Left leg-right arm voltages
C. Left leg-left arm voltages
D. Left leg-right leg voltages
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