The aVL lead shows the electrocardiogram in the below figure. ...

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The aVL lead shows the electrocardiogram in the below figure. This is indicative of the occlusion of which of the following coronary arteries?
 
  a. Left coronary artery
  b. Circumflex artery
  c. Right coronary artery
  d. Anterior interventricular branch of the left coronary artery

Question 2

A prolonged RR interval indicates which of the following kinds of cardiac arrhythmia?
 
  a. Atrial fibrillation c. Premature ventricu-lar beats
  b. Sinoatrial block d. Paroxysmal atrial tachycardia

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Answer to Question 1

ANS: B
The electrocardiogram strip shows ST segment elevation. This occurs in leads II, III, and aVL with the occlusion of the circumflex artery. Left coronary artery occlusion will cause an ST seg-ment elevation in lead I and a depression in lead III. Right coronary occlusion will cause ST segment depression in precordial leads V3 and V4. An occlusion of the anterior interventricular branch of the left coronary artery will cause an ST segment elevation in lead I and an ST segment depression in lead III.

Answer to Question 2

ANS: B
Sinoatrial blocks occur when the impulse generated at the sinoatrial node is blocked before it can enter the atrial muscle. On the electrocardiogram this is demonstrated by a sudden loss of P waves resulting from the absence of atrial depolarization. The contour of the QRS complex is normal, but the RR intervals are usually prolonged, indicating the presence of a junctional es-cape rhythm.

[PhilipSeeMore]

Excellent

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