6 - Arrhythmias

Question 1

Which is not one of the 3 most important steps in dx of arrhythmia?

a. rhythm regular or irregular
b. QRS complex narrow/wide
c. P wave bifid in 2, 3, aVF
d. P wave upright, inverted, saw tooth, absent

Answer 1

c

Question 2

Which is false?

a. cardioversion is best tx for sinus tachy
b. best to shock a pt w/ hemodynamically unstable tachyarrhythmia
c. AV dissoc is a characteristic of VT
d. treat underlying pulm dz is best for MAT

Answer 2

a

Question 3

which is first question in initial approach to arrhythmia?

a. rhythm regular?
b. QRS narrow or wide?
c. P wave bifid in 2 or taller than 2.5?
d. P wave upright, inverted, saw tooth, or absent?
e. QRS axis normal/abnormal?

Answer 3

b

Question 4

where do all arrhythmias with narrow QRS complexes arise from?

Answer 4

above the ventricles (SVT)

Question 5

what are the 2 arrhythmias with wide QRS complexes?

Answer 5

SVT w/ BBB (rare)

VT (life threatening)

Question 6

arrhythmias with narrow, regular QRS complexes

Answer 6

sinus tachy
atrial tachy
atrial flutter
AVNRT / AVRT

Question 7

causes of atrial tachy

Answer 7

structural atrial disease
sympathetic stimulation
toxins/drugs

Question 8

tx of atrial tachy

Answer 8

withdraw sympathetic stimuli/drugs
rarely use antiarrhythmics
often does not respond to cardioversion

Question 9

what should you think for atrial tachy with block?

Answer 9

digoxin toxicity

Question 10

sawtooth p waves =

Answer 10

atrial flutter

Question 11

cause of atrial flutter

Answer 11

diseased/dilated atria

Question 12

rate of atrial flutter vs atrial tachy

Answer 12

flutter ~ 300

tachy ~ 160

Question 13

tx of atrial flutter

Answer 13

unstable - synchronized cardioversion
slow AV conduction (metoprolol, verapamil or diltiazem)
convert back to sinus

Question 14

sign of AVNRT

Answer 14

no p waves

Question 15

AVNRT =

Answer 15

av nodal re-entrant tachy

Question 16

cause of AVNRT

Answer 16

micro-reentrant pathway, arrhythmia is usually paroxysmal and often triggered by PAC

Question 17

tx of AVNRT

Answer 17

unstable - cardioversion

block AV conduction - vagal enhancing maneuvers, adenosine, verapamil or diltiazem, beta blockers

Question 18

cause of AVRT

Answer 18

macro reentrant loop, often paroxysmal

Question 19

Types of Narrow Complex Regular Tachy:

• normal p waves >
• abnormal p waves >
• sawtooth waves >
• no atrial activity >

Answer 19

sinus tachy
atrial tachy
atrial flutter
AVNRT or AVRT

Question 20

differential for narrow QRS, irregular arrhythmias

Answer 20

MAT
atrial flutter w/ variable conduction
atrial fibrillation

Question 21

criteria for multifocal atrial tachy

Answer 21

narrow, irregular qrs
3+ distinct p waves
ventricular rate 100

Question 22

cause and tx of MAT

Answer 22

usually due to underlying pulm dz (ex COPD)

treat underlying dz - try to decrease sympathomimetics

Question 23

appearance of afib on ECG

Answer 23

absent p waves with irregular rate

Question 24

many cases of afib are caused by a focus in ____

Answer 24

pulm vein

Question 25

tx of afib

Answer 25

unstable - cardiovert
stable - slow ventricular response rate or electively cardiovert
if in afib for >48 hrs or unk time - anticoagulate or TEE to r/o thrombus, then cardiovert

Question 26

2 questions to ask after determining you have a wide complex tachyarrhythmia

Answer 26

are qrs complexes perfectly regular or slightly irregular?

are there p waves or evidence of atrial activity before each complex, or is there AV dissoc?

Question 27

causes of VTac

Answer 27

acute ischemia / MI
reentry around old scar or aneurysm
medications that prolong QT

Question 28

tx of VTac

Answer 28

unresponsive/pulseless - defib
unstable - synchronized cardioversion
stable - antiarrhythmic agents

Question 29

negative effects of antiarrhythmics

Answer 29

negative inotropy
QT prolongation
pro arrhythmic

Question 30

effect of suppressing PVCs

Answer 30

increased mortality

Question 31

amiodarone - mechanism

Answer 31

antiarrhythmic with beta blocking, Ca channel blocking, and direct effects on SA, AV nodes and atrial and ventricular tissues

Question 32

labs to monitor on amiodarone

Answer 32

check for bradycardia and heart block when starting

q6 mo : LFTs, thyroid, CXR for pulm fibrosis

Question 33

amiodarone drug interactions

Answer 33

blood thinners- increases INR

digoxin - increases levels