Section 2

Question 1

Commotio Cordis

Answer 1

A blunt trauma to the chest during the second half of the t wave causing early depolarization sending pt into cardiac arrest

Question 2

Role of electrolytes in cardiac function:
Sodium (Na+)

Answer 2

Flows into cell to initiate depolarization

Question 3

Role of electrolytes in cardiac function:
Potassium (K+)

Answer 3

Flows out of cell to initiate repolarization

Question 4

Role of electrolytes in cardiac function:
Hypokalemia

Answer 4

Increased myocardial irritability

Question 5

Role of electrolytes in cardiac function:
Hyperkalemia

Answer 5

Decreased automaticity/conduction

Question 6

Role of electrolytes in cardiac function:
Calcium (Ca++)

Answer 6

Maintains depolarization after initial Na+ influx and depolarization

Question 7

Role of electrolytes in cardiac function:
Hypocalcemia

Answer 7

Decreased contractility and increased myocardial irritability

Question 8

Role of electrolytes in cardiac function:
Hypercalcemia

Answer 8

Increased contractility

Question 9

Role of electrolytes in cardiac function:
Magnesium (Mg++)

Answer 9

Stabilizes cell membrane;
Acts in concert with K+ and against Ca++

Question 10

Role of electrolytes in cardiac function:
Hypomagnesemia

Answer 10

Decreased conduction

Question 11

Role of electrolytes in cardiac function:
Hypermagnesemia

Answer 11

Increased myocardial irritability

Question 12

Depolarization (Phase 0-2)

Answer 12

Electrical impulse that stimulates contraction
Stimulation causes Sodium ions to rush into cell, potassium ions start to leave while calcium enters the cell to maintain depolarization

Question 13

Repolarization (phase 3-4)

Answer 13

Potassium ions (K+) exit cell rapidly,
Sodium exit, potassium enters, (Na/K pump puts everything back in place, restoring balance)

Question 14

Refractory period (absolute/relative)

Answer 14

Period when cell is depolarized or in the process of repolarizing (T-wave)
Absolute: cardiac cells can’t respond to any stimulus
Relative: partial repolarization, may depolarize to stimulus

Question 15

SA node supplied by what coronary artery?

Answer 15

RCA

Question 16

Bachman bundle

Answer 16

Interatria pathway connecting L/R atria after SA node

Question 17

Wenckebach tract

Answer 17

From SA node, internodal tract toward AV node

Question 18

Thorel Tract

Answer 18

Posterior intermodal pathway from SA node

Question 19

AV node purpose/supplied by what coronary artery

Answer 19

Delays impulse for 0.12-0.20 seconds allowing atria to empty into ventricles
Mostly RCA, sometimes Cx

Question 20

James fibers

Answer 20

Fibers in atrial internodal pathways extending into ventricles, bypassing AV node

Question 21

Mahain Fibers

Answer 21

Branch from AV node, bundle of His, bundle branches,
Common pathway for reentrant dysrhythmias

Question 22

Bundle of Kent

Answer 22

Usually between left atria and left ventricle (sometimes right)
Creates delta waves

Question 23

Sympathetic nervous system effect on heart

Answer 23

Accelerator
Releases norepinephrine to stimulate SA, AV, ventricles

Question 24

Parasympathetic system effect on heart

Answer 24

Inhibitory (lowers HR)
Stimulation of vagus nerve effects SA node, atrial muscle, AV junction
Vagus stimulation releases acetylcholine To signal SA node to lower heart rate

Question 25

Ways of stimulating vagus nerve

Answer 25

Increased pressure on corotid sinus, straining/forced exhalation against closed glottis (valsalva maneuver), distention of hollowed organ (bladder/stomach)

Question 26

Parasympathetic blocker (medication) and natural parasympathetic recycling agent

Answer 26

Atropine, blocker Acetylcholinesterase breaks down acetylcholine to be recycled, raising HR

Question 27

V1/2 views?

Answer 27

Septum

Question 28

V3/4 views?

Answer 28

LV anterior wall

Question 29

V5/6 views?

Answer 29

LV lateral wall

Question 30

aVL views?

Answer 30

LV lateral surface