[MCQ] Principles of Electrophysiology- Part 1

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Principles of Electrophysiology- Part 1 | Principles of Electrophysiology- Part 2

1. Electrocardiogram (ECG) was developed by ?
A. Hewlet
B. Judkin
C. Einthoven
D. White

2.  Sinoatrial (SA) node is located at the junction of ?
A. Right atrium and superior vena cava
B. Right atrium and inferior vena cava
C. Right atrium and left atrium
D. Right atrium and coronary sinus

3.  PR interval of ECG represents time needed for activation of ?
A. Both atria
B. Atrioventricular node (AVN)
C. Both atria + Atrioventricular node (AVN)
D. Both atria + AVN + His Purkinje system

4.  Which of the following statements is false ?
A. Body surface ECG is the timed sum of cellular action potentials in atria & ventricles
B. Repolarization occurs first on endocardium then proceeds to epicardium
C. Activation of atria & AV node is PR interval
D. QT interval is duration of activation & recovery of ventricles

5.  Duration of action potential in cardiac myocytes is ?
A. 20 – 40 ms
B. 80 – 1600 ms

C. 200 – 400 ms
D. 500 – 800 ms

6. Which of the following participate in the cardiac myocyte action potential ?
A. Ion channels
B. Pumps, transporters
C. Exchangers
D. All of the above

7. Diastole corresponds to which phase of action potentials ?
A. Phase 1
B. Phase 2
C. Phase 3
D. Phase 4

8.  Which of the following gene is responsible for ventricular repolarization ?
A. KCNJ2
B. SCN5A
C. CACNA1C
D. SLC8A1

9.  Which of the following is principal current during phase 4 ?
A. IK1
B. Ito
C. IKr
D. IKs

10.  Which of the following determines the resting membrane potential of the myocyte ?
A. IK1
B. Ito
C. IKr
D. IKs

11.  Which of the following causes phase 3 repolarization ?
A. Inactivation of the calcium current
B. Persistent activation of IKr
C. Persistent activation of IKs

D. All of the above

12.  Sodium-calcium exchanger transports how many Na+ for one Ca2+ ?
A. 1
B. 2
C. 3
D. 4

13.  Automaticity is a property of ?
A. Sinoatrial (SA) node
B. His-Purkinje system
C. Coronary sinus
D. All of the above

14.  Early afterdepolarizations occur during ?
A. Phases 0 and 1 of the action potential
B. Phases 1 and 2 of the action potential
C. Phases 2 and 3 of the action potential
D. Phases 3 and 4 of the action potential

15.  Delayed afterdepolarizations occur after completion of ?
A. Phase 1 of action potential
B. Phase 2 of action potential
C. Phase 3 of action potential
D. Phase 4 of action potential

16.  Cellular feature common to induction of DADs is the presence of ?
A. Increased Ca2+ load in the cytosol
B. Increased Na+ load in the cytosol
C. Increased K+ load in the cytosol
D. Increased Mg2+ load in the cytosol

17. Which of the following enhance Ca2+ loading sufficiently to produce DADs ?
A. Digitalis glycoside toxicity
B. Catecholamines
C. Myocardial ischemia
D. All of the above

18. Which of the following about connexins is false ?
A. Gap junction membrane-spanning protein
B. CMT1X is caused by mutations in connexin 32 gene
C. Mutations in connexin 26 causes progressive hearing loss
D. None of the above