What are the atrial and ventricular rates for lead I in the ...

[captainjonesify]

What are the atrial and ventricular rates for lead I in the following electrocardiogram? Atrial Rate Ventricular Rate
 
  a. 75 225 c. 300 75
  b. 180 90 d. 135 45

Question 2

The heart block that causes dropped beats and that is often the result of increased parasympa-thetic tone is called _____ block.
 
  a. Sinoatrial c. First-degree atrio-ventricular
  b. Mobitz type I d. Left bundle branch

[Perkypinki]

Answer to Question 1

ANS: C
The strip is 2.4 seconds long, so 60  2.4 = 25, making 25 the multiplication factor. Because there are 3 ventricular beats, the ventricular rate is 3 times 25, or 75 beats/min. There are 12 P waves, making the atrial rate 12 times 25, or 300 beats/min.

Answer to Question 2

ANS: B
Dropped beats are characteristic of second-degree atrioventricular blocks, which consist of Mo-bitz type I and Mobitz type II blocks. These dropped beats are a result of the atrioventricular node's inability to conduct impulses from the sinoatrial node. Sinoatrial blocks are indicated by a sudden loss of P waves. First-degree atrioventricular blocks are indicated by a prolongation of the PR interval. Left bundle branch blocks are indicated by the absence of Q waves in the left limb leads.