Questions

multiple choice questions

MCQs

The MCQ section in Anaesthesia and Intensive Care Medicine is designed to test your knowledge of selected topics in this issue of the journal. The correct answers are given at the foot of the page. Henry G W Paw is Consultant in Anaesthesia and Intensive Care at York Hospital, and Clinical Senior Lecturer at the Hull York Medical School, UK.

Questions 1 Initiation and regulation of the heartbeat (pages 255–258) The sinoatrial (SA) node: A

  Lies in the groove where the superior vena cava joins the right atrium

B

  Does not require a nerve impulse to initiate the heart beat

C

  Discharges automatically 60 times per minute

E

  Sympathetic stimulation facilitates closure of Ca2+ channels

D

  The T wave represents ventricular depolarization

  A normal ECG may be present when the circulation is grossly inadequate

(pages 289–293) Adenosine may be used in the following situations:

  Vagal stimulation activates M2-receptors in the SA node

A

  Second degree AV block

C

  Supraventricular tachycardia

B D E

  Asthma

  Ventricular tachycardia

  Concurrent treatment with β-blocker

5 Anti-arrhythmic drugs

A

  Myocardial muscle cells discharge automatically 25 times per minute

B

  In its phases of polarization, the cell is hyperexcitable during phases 1 and 2

E

D

4 Cardiac arrhythmias in the critically ill

(pages 259–263) The following statements regarding myocardial cells are true:

D

  QRS complex greater than 0.12 seconds represents conduction delay

E

2 Myocardial action potential

C

C

(pages 294–297) Anti-arrhythmic drugs that predominantly block the sodium pump include: A

  Amiodarone

C

  Lidocaine

B

  The duration of depolarization is 2 ms

  Phase 0 is the result of Ca2+ entering through the fast-opening Ca2+ channels

D E

  Repolarization after the plateau is due to a delayed increase in K+ permeability

  Flecainide

  Propafenone   Verapamil

6 Antihypertensive drugs (pages 298–302) Drugs with α antagonist properties include:

3 The electrocardiogram (pages 264–266) Concerning the ECG: A

B

A

  Clonidine

C

  Phenoxybenzamine

B

  The P wave represents atrial depolarization

  The PR interval starts from the beginning of the P wave and ends at the end of the R deflection

D E

  Doxazosin

  Phentolamine   Hydralazine

Correct answers: 1 (A, B, D) 2 (E) 3 (A, C, E) 4 (C, E) 5 (B, C, D) 6 (B, C, D) ANAESTHESIA AND INTENSIVE CARE MEDICINE 7:8

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© 2006 Published by Elsevier Ltd.