Week 1 etc.

Question 1

Firing rate of:
SA node
AV node
Bundle of His
Purkinje fibers

Answer 1

70-80 (ipm)
40-60
40
15-20

Question 2

Absolute refractory
Relative refractory
Supranormal period

Answer 2

No repolarization can occur because most Na+ channels are closed.
Cell is almost repolarized, but can fire an AP with a large enough impulse.
During hyperpolarization.

Question 3

Chronotropic

Answer 3

Changes the HR.

Question 4

Dromotropic

Answer 4

Changes the speed of conduction.

Question 5

Iontropic

Answer 5

Changes the strength of contraction.

Question 6

Lusitropic

Answer 6

Changes rate of relaxation.

Question 7

Sympathetic stimulation of the heart

Answer 7

Stimulus carried via cardiac splanchnic ns. to SA/AV nodes and cardiac tissue.
Receptor is B-1.

Question 8

PSNS stimulation of the heart

Answer 8

Stimulus is carried via vagus n. to SA/AV nodes and cardia tissue. ACh is NT and receptor is muscarinic.

Question 9

Lead I placement

Answer 9

RA to LA

Question 10

Lead II placement

Answer 10

RA to LL

Question 11

Lead III placement

Answer 11

LA to LL

Question 12

Draw the axis of standard and augmented leads

Answer 12

Draw

Question 13

Inferior region and RCA are seen best in which leads? (3)

Answer 13

Leads II, III, aVF

Question 14

Septal region and LAD are seen best in which leads? (2)

Answer 14

V1, V2

Question 15

Anterior region and LAD are seen best in which leads (3)

Answer 15

V2, V3, V4

Question 16

Lateral region and circumflex a. are seen best in which leads? (5)

Answer 16

I, aVL, V4, V5, V6

Question 17

P wave is upright in:

Inverted in:

Answer 17

I, II, aVF, V4-6

aVR

Question 18

T wave is upright in:

Inverted in:

Answer 18

I, II, V3-6

aVR

Question 19

Normal duration of PR interval

Answer 19

0.12 to 0.20 sec.

Longer than 0.20 could suggest AV block.

Question 20

Normal duration of QRS complex

Answer 20

0.05 to 0.10 sec.

Longer than 0.12 could suggest bundle branch block or hypertrophy.

Question 21

ST segment morphology

Answer 21

Should be baseline, but should not be elevated over 1 mm in standard leads and 2 mm in chest leads. Should not be depressed more than 0.2 mm (indicative of ischemia or transmural injury).

Question 22

T wave height

Answer 22

Up to 5 mm in standard leads and 10 mm in chest leads.

Question 23

Inverted T waves are associated with:

Answer 23

Ischemia

Question 24

U waves can be associated with:

Answer 24

Hypokalemia

Question 25

QT interval duration

Answer 25

Avg is 0.35 sec., but no longer than 0.45 sec.

Question 26

Draw the cardiac axis

Answer 26

Draw

Question 27

What happens to the cardiac axis in a patient with ventricular hypertrophy?

Answer 27

The axis moves to the side of hypertrophy.

Question 28

What happens to the cardiac axis in an MI?

Answer 28

Axis deviates from the side of the infarct.

Question 29

Excitation-coupling mechanism

Answer 29

Depolarization causes Ca to flow into the cell via L-type channels. Ca binds to ryanodine receptors causing the SR to leak more Ca. Ca binds to troponin C, causing tropomyosin to move away and allows myosin to bind actin and contraction occurs.

Question 30

Relaxation can occur by:

Answer 30

Ca ATPase | CNX

Question 31

a wave c wave v wave

Answer 31

Increase in atrial pressure. Due to increasing ventricular pressure. Pressure while the atrium fills with blood.

Question 32

S1 S2 S3 S4

Answer 32

Closing of the AV valves. Closing of the SL valves. Rapid ventricular filling. Atrial contraction.

Question 33

Receptor and NT setup for Sympathetic NS

Answer 33

Draw

Question 34

Receptor and NT setup for PSNS

Answer 34

Draw

Question 35

Sympathetic activation of SA/AV node

Answer 35

NE binds B1 causing an increase in Na (f) channels which increases phase 4 and HR.

Question 36

Sympathetic activation of cardiac myocytes

Answer 36

NE binds B1 receptor that stimulates L-type Ca channels to stay open longer which increases contractility and SV.

Question 37

Sinus arrhythmia

Answer 37

Initiated by the SA node. | Wave morphology is normal, but time between each cycle varies.

Question 38

Junctional rhythm

Answer 38

Initiated by the AV node. P waves are absent or trail the QRS complex. Rate is about 40-60.

Question 39

Premature atrial contraction (PAC)

Answer 39

P waves come earlier than expected based on previous cycle. Normal.

Question 40

Multifocal atrial tachycardia (MAT)

Answer 40

3 different P waves caused by different atrial foci causing a depolarization. Rate is tachycardic.

Question 41

AFib

Answer 41

Continuous atrial spikes with no discernable P or T waves. | Spacing in QRS is variable.

Question 42

Supraventricular tachycardia (SVT)

Answer 42

P and T waves are indistinguishable from QRS. Can be in alteration.

Question 43

PVC

Answer 43

P wave is absent before a QRS complex that is long and wide.

Question 44

Vtach

Answer 44

Big, wide QRS complex in rapid succession w/ no identifiable P waves. Rate is tachy.

Question 45

VFib

Answer 45

Peaks/waves are not distinguishable. | Caused by multiple ventricular foci firing without synchronicity.

Question 46

AV block

Answer 46

PR interval is longer than 0.2 s.