Dubin Ch. 4 Rate

Question 1

The 1st consideration when reading an EKG is _____

Answer 1

Rate

pg 65

Question 2

What is the heart’s dominate center of automaticity?

What is its inherent rate?

Answer 2

SA Node, 60-100 bpm

pg 66

Question 3

Where is the SA node located?

Answer 3

upper-posterior wall of the right atria

pg 66

Question 4

What rhythm results from parasympathetic excess? What is the rate?

Answer 4

Bradycardia, <60 bpm

pg 67

Question 5

What rhythm results from sympathetic excess? What is the rate?

Answer 5

Tachycardia, >100 bpm

pg 68

Question 6

Automaticity foci are capable of pacing the heart in emergency situations and are also known as __________. Where are they located?

Answer 6

potential pacemakers
atria, ventricles and AV junction
pg 68-69

Question 7

Where in the AV node are automaticity foci located?

Where in the ventricles are automaticity foci located?

Answer 7

AV junction, Purkinje fibers (His Bundle and Bundle Branches)
pg 69

Question 8

What are the general range of pacing for the following foci locations? Atria, AV Junction, Ventricles

Answer 8

Atria = 60-80 bpm
AV Junction = 40-60 bpm
Ventricles = 20-40 bpm
pg 70

Question 9

Describe SA Node overdrive suppression.

Answer 9

Any automaticity center will overdrive-supress all others that have a slower inherent pacemaking rate.
pg 71

Question 10

In SA Node failure, describe the levels of foci that take over when and at what rate?

Answer 10

Atria focus becomes the active pacemaker at 60-80 bpm
If atria focus fails, AV Junctional focus kicks in at 40-60 bpm
If the AV junction focus fails then the ventricle focus becomes the active pacemaker at 20-40 bpm.
pg 72-74

Question 11

To calculate the rate on an EKG, 1st find a _____ that peaks on a heavy black line. This is your “start”.
Then count down __, __, __, __, __, __ for each consecutive heavy black line until the next _____. This will give you an immediate estimate of the rate.

Answer 11

R wave
300, 150, 100, 75, 60, 50…
R wave
pg 79-84

Question 12

The length of a _____ _____ can be measured from a specific wave until that next wave is repeated.
To determine the rate, for marked bradycardia, count the # of cardiac cycles in a __ _____ strip and multiply by ___.

Answer 12

cardiac cycle
6 second
10
pg 93

Question 13

The general, average rates of irregular rhythms are usually determined by using what method?

Answer 13

Count # of cardiac cycle in a 6 sec strip and multiply by 10.
pg 96