HLTH 2501: dysrhythmias

Question 1

what is a dysrhythmia?

Answer 1

deviations from the normal cardiac cycle of rhythm which are caused by abnormalities in the heart’s pumping cycle; impact normal filling and emptying cycles of the heart chamber

Question 1

what can dysrhythmias be caused by?

Answer 1

inflammation, scar tissue, a MI, electrolyte abnormalities, fever, hypoxia, stress, infection, or drug toxicity

Question 2

what can a slight increase in heart rate cause?

Answer 2

can increase CO, preventing adequate filling during diastole

Question 3

what can a slight decrease in heart rate cause?

Answer 3

reduced output to the tissues, including the heart and the brain

Question 4

brachycardia

Answer 4

< 60 bpm and can be caused by PNS activation

Question 5

tachycardia

Answer 5

100-160 bpm and can be caused by SNS, exercise, fever, or stress

Question 6

sick sinus syndrome

Answer 6

alternating bradycardia and tachycardia

Question 7

most common dysrhythmias

Answer 7

atrial conduction abnormalities

Question 8

atrial conduction abnormalities

Answer 8

associated with premature atrial contractions that are either extra contractions or ectopic beats

Question 9

what are palpitations

Answer 9

rapid or irregular heart contractions that often arise from excessive caffeine, smoking, or stress

Question 10

atrial flutter

Answer 10

an atria heart rate of 160-350 bpm; AV nodes are delaying conduction

Question 11

atrial fibrillaton

Answer 11

more than 350 bpm; causes pooling of blood in the atria

Question 12

when does heart block occur?

Answer 12

when conduction is excessively delayed or stopped at the AV node or bundle of His

Question 13

3 types of heart blocks

Answer 13

first degree, second degree, or total or third degree

Question 14

first degree heart block

Answer 14

when the conduction delay prolongs the PR interval

Question 15

PR interval

Answer 15

the time between atrial and ventricular contractions

Question 16

second degree heart block

Answer 16

when there is a longer delay that leads to a missed ventricular contraction

Question 17

total or third degree heart block

Answer 17

occurs when there is no transmission of impulses from the atria to the ventricles; causes the ventricles to contract spontaneously as a slow rate that is independent of the atria; CO is greatly reduced

Question 18

bundle branch block

Answer 18

interference with conduction in one of the bundle branches; does not alter CO

Question 19

ventricular tachycardia

Answer 19

is likely to reduce CO because the filling time is being reduced

Question 20

ventricular fibrillation

Answer 20

muscle fibres contract rapidly and are thus ineffective as ejecting blood; can cause hypoxia to occur in the myocardium

Question 21

PVCs

Answer 21

additional beats that arise from a ventricular muscle cell or ectopic pacemaker; do not interfere with function but can be concerning

Question 22

treatment for dysrhythmias

Answer 22

can be removing certain drugs like beta blockers or potassium sparing drugs or by administering antiarrhythmic drugs like digoxin

Question 23

what does digoxin do?

Answer 23

slows AV node conduction and strengthens the contraction; useful for atria dysrhythmias

Question 24

how are SA node problems treated?

Answer 24

by using a pacemaker that can stimulate a heart contraction when needed

Question 25

what is treatment for life-threatening dysrhythmias

Answer 25

defibrillators that shock the heart to interrupt the disorganized activity

Question 26

cardiac arrest

Answer 26

the cessation of all activity in the heart; occurs when there are no impulses, hence no CO and no supply of O2 to the brain and heart

Question 27

what can cardiac arrest occur as a result of?

Answer 27

excessive vagal nerve stimulation, drug toxicity, or severe shock