Question

31. The most common type of sinus arrhythmia, the one related to respiration, is:

a. a normal phenomenon commonly seen in middle aged adults

b. caused by decreased vagal activity

c. caused by the sympathetic effect on the SA node

d. extremely rare in children

20. Monitoring lead MCL1 is obtained by attaching the positive electrode from lead ______________:

a. II, to the left chest below the clavicle

b. II, to the middle of the sternum at the level of the fourth intercostal space

c. III, to the left side of the sternum in the fourth intercostal space

d. III, to the right side of the anterior chest in the fourth intercostal space next to the sternum

10. The vagus nerve is part of the parasympathetic nervous system. Slowing of the heart rate by the vagus nerve occurs when:

a. The nerve fires more rapidly

b. The nerve is blocked by atropine

c. The nerve is severed

d. The patient is given a stimulant

Answer 1

Answer1- a a normal phenomenon commonly seen in middle aged adults

Explanation- respiratory sinus arrythemia is normal phenomenon in which heart rate increase in respiration and decrease with expiration.most commonly seen in young healthy adults and children also.

Answer 2- d III To the right side of anterior chest in 4th intercostal space next to the sternum.

Explanation- MCL1 is Modified Chest Lead or Marriott's Chest Lead.the positive electrode is in 4th intercostal space ,right sternal border and the negative electrode in on left arm.

Answer3- a the nerve fired more rapidly.

Explanation- The vagus nerve innervating the SA node normally at rest a small vagak tone is also present which maintain the heart rate within 60-80 per minute

It is most important of parasympathetic neural system. Overstimulation of vagus nerve causes decreay heart rate and blood pressure