Lecture 1 Anti-arrhythmics basic

Question 1

The beating heart relies on sequential changes in ____ ____

Answer 1

membrane potentials

Question 2

what is the conduction pathway

Answer 2

SA-atria-AV node-common bundle–bundle branches–fasicles–purkinje fibers–ventricles

Question 3

cardiac muscle contains ___ ____, allowing for simultaneous propagation of action potentials

Answer 3

gap junctions

Question 4

myocardial APs occur in cardiac muscle, the ____ and _____

Answer 4

bundle of his, purkinje fibers

Question 5

Myocardial AP:phase 0 = rapid ____ and depolarization, due to inward _____

Answer 5

upstroke; sodium

Question 6

Myocardial AP: Phase 1 = initial _____ due to inactivation of voltage gated ___ channels and opening of some ____ channels

Answer 6

repolarization;Na, potassium (outward)

Question 7

myocardial AP:phase 2 = ____ due to ____ influx through voltage gated channels, balancing ____ efflux. ____ influx triggers __ release from the SR and myocyte contraction

Answer 7

plateau, calcium;potassium; calcium, calcium

Question 8

myocardial AP:phase 3 = rapid ____ due to massive ___ efflux due to pening of voltage gated ____ channels and closure of voltage gated ____ channels

Answer 8

repolarization, K;slow K; Ca

Question 9

myocardial AP:phase 4 = resting potential due to high ___ permeability. what is the resting potential usually?

Answer 9

potassium negative 90 mV

Question 10

myocardial tissue at resting potential:____ channels are typically closed = no movement of ions despite high concentration gradient. inward ____ ___ channels are open, allowing free movement

Answer 10

sodium;rectifier potassiumn

Question 11

pacemaker APs occur in the ___ and ___ nodes. they have an _____ resting potential

Answer 11

SA, AV; unstable

Question 12

PR interval is the time from ______ to _____. it corresponds to ____ conduction

Answer 12

atrial depolarization, ventricular depolarization;AV node

Question 13

pacemaker AP:phase 0 = ____ due to opening of voltage gated ___ channels.

Answer 13

upstroke, calcium

Question 14

pacemaker AP:phase 3 = inactivation of the ___ channels and increased activation of ___ channels = ___ efflux

Answer 14

calcium, potassium; potassium

Question 15

pacemaker AP: phase 4 = slow spontaneous _____ depolarization as a result of increased ___ conductance (through what channnel?)

Answer 15

diastolic; sodium and potassium; “funny current”

Question 16

the slope of phase ___ in the SA node determines HR

Answer 16

4

Question 17

chronotropic effects: the sympathetic system causes an increase in phase ___ depolarization due to increased ____ channel opening

Answer 17

4; funny;easier to reach threshold

Question 18

which has a longer AP, skeletal or cardiac muscle?

Answer 18

cardiac (much slower AP, longer contraction)

Question 19

what channel is open during the refractory period in cardiac muscle? what channel is inactivated?

Answer 19

potassium; sodium

Question 20

what are the 2 “triggered arrythmias”?

Answer 20

Early afterdepolarization (EAD); delayed after-depolarization (DAD)

Question 21

ectopic foci are due to an abnormal ____ site, typically occuring after ____

Answer 21

pacemaker; ischemia

Question 22

ischemic cardiac tissue is ___polarized relative to normal tissue,

Answer 22

de

Question 23

an EAD occurs in the late phase ____. EAD’s are due to prolonged ____. a DAD occurs in the early phase ___. DAD’s are due to ____ overload

Answer 23

3, plataeu;4, calcium

Question 24

____ are exacerbated by slow HRs, such as long QT arrhythmias (ie Torsades). ____ are exacerbated by rapid HRs, such as MI induced arrythmia

Answer 24

EAD,DAD

Question 25

Torsades de pointes is predisposed by a long ____. It is a polymorphic ventricular ____, characterized by shifting ___ waveforms. can progress to ____

Answer 25

QT; tachycardia, sinusoidal;vFib

Question 26

re-entry is due to ____ impulse exciting areas of the heart more than once (circuit movement). can be due to a ___ conduction time and a ___ refractory period

Answer 26

one; long, short

Question 27

____ reentry is when there is reentry between the atria and ventricles due to a ____ pathway. what is an example?

Answer 27

global, acceossory;wolf parkinson white

Question 28

Premature ventricular contraction:beat originates in the ____, causing the ventricles to contract before the ___ and resulting in a decrease in the amount of blood pumped to the body

Answer 28

ventricles; atria