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Flashcards in Conduction disorders Deck (89)
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1

What do the PQRST of an ECG represent

P: atrial depolarization
PR: AV node delay
QRS: Ventricular depolarization
ST: beginning of repolarization
T: Ventricular repolarization

2

"How to read a rhythm strip"

Assess rate
Regular or irregular
Wide or narrow QRS
P wave to QRS relationship

3

What is the big box method for counting HR

300
150
100
75
60
50
(5 boxes= 1 second)

4

What is bradycardia due to

defect in impulse formation (SA) or impulse conduction (heart block)

5

What constitutes "NSR"

rate 60-100
one P for every QRS, one QRS for every P
P waves have same morphology
QRS (in same leads) have same morphology

6

What are symptoms of rhythm disorders

fatigue, palpitations, syncope, dizzy spells

7

Whats important to check on PE

thyroid exam; hypothyroid can cause bradycardia
Hyperthyroid can cause arrhythmia

8

What must you fix in order to correct chronic hypokalemia

Mg levels

9

What is the initial survey of ACLS

Circulation
Airway
Breathing

10

What are the class I anti-arrhythmic drugs

Na channel blockers;
1a: Mod Na block, some K & Ca. Prolong QRS
1b: weak Na block. Min ECG changes. used for Ventricular arrhythmias
*1c: Strong Na block. wide QRS, SA node depression. NOT for CAD

11

What are the Class II anti-arrhythmic drugs

Beta blockers: decrease sinus rate, prolong PR

12

What are the Class III anti-arrhythmic drugs

K channel blockers: prolong QT
*amiodarone prolongs QT but side effects aren't as bad

13

What are the class IV anti-arrhythmic drugs

Ca channel blocker: decrease sinus rate, prolong PR
decrease contractility and cause edema

14

What are other anti-arrhythmic drugs

Digoxin: increase vagal tone/ AV block
Adenosine: AV node blocker (half life 10 seconds)

15

What is sick sinus syndrome

chronic SA node dysfunction diagnosed by symptoms (brady, sinus arrest, tacky-brady) plus ECG findings)
-Usually d/t fibrosis form aging

16

What is sinus bradycardia

Normal rate and rhythm but HR under 60
Caused by fibrosis, acute injury, or med s/e

17

What are symptoms of bradycardia

fatigue, SOB, syncope

18

When would you place a pacemaker in a bradycardia patient

If symptomatic and d/t irreversible cause

19

How do you treat sick sinus syndrome

Treat tacky if sx
stop offending agents if brady
Permanent pacemaker to control tachy-brady

20

What is sinus arrest

failure of sinus node to initiate impulse causing pause >2 seconds

21

When would you pace a sinus arrest patient

if pause is > 6 seconds

22

What is tachy-brady syndrome

intermittent fast and slow rates from SA node or atria (<60, >100)
-periods of AFib,

23

When would you pace a tachy-brady patient

If Afib is present as well

24

What is first degree AV block

PR interval >200 sec (one big box)
(patient asymptomatic, no treatment)

25

What is second degree AV block, Mobitz I

Wenkeback! progressive prolongation until failure to conduct and ventricular beat dropped
site of block is in AV node

26

How do you treat Wenkebach

Not dangerous, so no treatment
usually asymptomatic

27

What is second degree AV block, Mobitz II

Fixed PR interval, but dropped QRS
Block is in the HIS (below AV)
EMERGENCY! can lead to complete heart block

28

What is complete heart block

no conduction from atria to ventricles
P wave independent form QRS with ventricular escape rhythm
EMERGENCY! must pace

29

What are symptoms of complete heart block

syncope, SOB, HF, fatigue

30

What are QRS width measurements of bundle branch blocks

Incomplete: 0.10-0.12
Complete: 0.12 or more
(wider QRS= more extensive block)