Lecture 25 10/18/23

Question 1

What is the chronotropic effect of sympathetic activation?

Answer 1

increased sinus rate

Question 2

What is the chronotropic effect of parasympathetic activation?

Answer 2

decreased sinus rate

Question 3

What is the dromotropic effect of sympathetic activation?

Answer 3

increased rate of conduction through AV node/bundle

Question 4

What is the dromotropic effect of parasympathetic activation?

Answer 4

decreased rate of conduction through AV node/bundle

Question 5

What is the role of an EKG?

Answer 5

to measure electrical potential difference

Question 6

How does a positive deflection occur on an EKG?

Answer 6

a wave of depolarization towards the positive electrode causes a positive deflection

Question 7

How does the normal heart depolarize?

Answer 7

-right to left
-cranial to caudal
-dorsal to ventral

Question 8

What does the P wave represent?

Answer 8

atrial depolarization

Question 9

What does the QRS complex represent?

Answer 9

ventricular depolarization

Question 10

What does the T wave represent?

Answer 10

ventricular repolarization

Question 11

How can a T wave appear?

Answer 11

-positive
-negative
-biphasic

Question 12

What does a QRS complex always indicate?

Answer 12

ventricular activation

Question 13

How can electrical cardiac activity be described by a vector?

Answer 13

based on magnitude and direction

Question 14

What are the diagnostic utilizations of EKG?

Answer 14

-description of rate/rhythm (main use)
-chamber enlargement/heart failure
-ischemia/inadequate blood supply

Question 15

What does important diagnostic information relate to?

Answer 15

-rate
-consistency of RR intervals/heart cycle length
-relationship between atrial and ventricular activity
-determination of QRS origin

Question 16

How is a heart rate calculated from an EKG?

Answer 16

-at 50mm/sec, 30 boxes = 3 sec
-HR = number of complexes in 3 sec x 20

Question 17

What is RR interval?

Answer 17

the cycle length/heart period

Question 18

How does heart rate relate to RR interval?

Answer 18

HR = 60/RR in seconds

Question 19

What are the characteristics of supraventricular QRS origin?

Answer 19

-normal origin
-activation through both bundle branches
-narrow QRS
-occurs proximal to bifurcation of His/at nodes

Question 20

What are the characteristics of ventricular QRS origin?

Answer 20

-abnormal origin
-takes longer than normal due to bundle branches not being involved
-wide QRS
-occurs distal to bifurcation of His/in ventricular walls

Question 21

How can heart rate be calculated from RR?

Answer 21

60/(number of boxes/10)