Ventricular arrhythmias

Question 1

3 types of vent arrythms

Answer 1

1. V. Tachy
   - monomorphic
   - poly morphic
2. V. flutter
3. V. fib

Question 2

what is most important question to ask

Answer 2

does VT occur in setting of a normal heart

- organized VAs almost never caused by ischemia

Question 3

4 things seen on ECG in monomorphic VT

Answer 3

1. wide complex, originated from Vent
2. 120-250bpm, at least 3 beats
3. sustained = > 30 secs
4. consitent beat-beat QRS morphology

Question 4

2 main causes of VT

Answer 4

1. reentry
   - scarring
   - His-purk disease
   - idiopathic
2. automatic or triggered
   - peri-infarction
   - normal heart - catecholamine sensitive

Question 5

3 methods to diff. VT from SVT w/aberancy

Answer 5

1. HX
2. PhX
3. ECG

Question 6

what are Hx predictors of VT

Answer 6

1. age>40
2. history of CAD, previous MI
3. previous VT

Question 7

2 Phx signs

Answer 7

1. hemodyanamic stability
   - not too helpful, because young ppl can stand it
2. AV dissociation
   - cannon A waves in JVP

Question 8

5 main ECG criteria to differentiate

Answer 8

1. AV dissociation
2. rate - not helpful
3. QRS axis
4. QRS duration
5. QRS morpho

Question 9

what does AV dissociation mean and 3 things to look for

Answer 9

diagnostic of VT

1. fusion beats - part of one uses H/P system
2. capture beats - one fully down H/P
3. p -waves marching

Question 10

what does axis tell you

Answer 10

high prob of VT if axis is right superior (+ in AVR)

Question 11

what does QRS duration tell you

Answer 11

• > 140ms is 100 spec. for VT
• wider in myocardial disease, metabolic abnormal
• narrower with focus close to H/P system

Question 12

what are 3 questions about QRS morphology

Answer 12

ANY yes = VT, all 3 NO = SVT

1. absence of RS in all precorial leads
2. onset R to nadir S > 100ms in any V lead
3. morphology criteria in both V1-2 and V6

Question 13

what are morphology criteria

Answer 13

LBBB like QRS
V1or2
- R>30ms wide
- >60ms to nadir of S
- notched S
V6
- QR or QS
- monophasic R

Need both 1-2 and 6 to be met

Question 14

3 points to remember

Answer 14

1. in WCT, Vt is far more common than SVT
2. if structrual heart diease present, PPV for Vt = 95
3. can make correct diagnosis in most patients if apply criteria

Question 15

what is poly morphic VT

Answer 15

not a nice repeating wave- need a code blue

• ischemia most common cause
• may be assoc. with long QT, but not always
• signature is usually sinus rythm and onset of poly VT with short couple PVC (

Question 16

3 other important cause of poly VT

Answer 16

1. bradycard
2. hypokalemia
3. hypomagnesia

Question 17

what is long QT syndrome

Answer 17

• genetic defect in K channed
• prolonged repolarization
  QT>450 in men
  >460 in women

Question 18

3 ECG signs of V flutter

Answer 18

1. monomorphic
2. rate>250
3. usually hemo unstable and treated as fib

Question 19

3 ECG signs of V fib

Answer 19

1. polymorphic
2. rate > 250
3. can be very fine

Question 20

Tx of VT

Answer 20

if unstable -shock
- do NOT give AV node blockade to PTs with WCT unless previous documented benefit or are sure this is not pre-ecxited Afib

Question 21

5 ER scenarios

Answer 21

1. mono VT with structural HD
2. poly VT without long QT
3. mono VT without structural HD
4. poly VT with long QT
5. vent. fib/flutter

Question 22

what is and TX of xmono VT with structural HD

Answer 22

• related to reentryaround scar of old MI
• shock, amiodarone
• need to R/O ischemia as precipitant

Question 23

what is and TX of poly VT without long QT

Answer 23

may be ischemia, lyte abnormal, catecholamine
TX
- amiodarone, IV Mg, shock
- then ischemia mgmt and eval

Question 24

what is and TX of xmono VT without structural HD

Answer 24

• unlikely ischemia related
• most likely idiopathic benign
  TX
• very rare
• procainamide and or amiodarone

Question 25

what is and TX of poly VT with long QT

Answer 25

• torsades de pointes
• may be secondary to drugs (many) or genetics
  Tx
• IV Mg
• correction of lytes
• removal of meds
• isoproterenol

Question 26

Tx of flutter/lib

Answer 26

shock
treat underlying cause
- metabolic
- drugs
- ischemia