Conduction Abnormalities

Question 1

What is required for normal QRS and T wave morphology?

Answer 1

Normal RV and LV chamber sizes

Question 2

What are charicteristics of Bundle Branch Blocks?

Answer 2

One Vent. Activates First, then activates the other
-signal is propagated through muscle
QRS is prolonged
looks same as ventricular premature or paced beat

Question 3

What is the difference between LBBB and RBBB?

Answer 3

LBBB Broad QS in V1 and broa, slurred R wave in V6
-Worse Prognosis
RBBB Broad QRS
rSR’ Pattern in V1 and deep, broad S wave in V6

Question 4

What does a wider than normal wave mean?

Answer 4

Impulse is travelling through muscle.

Question 5

What causes a RBBB(unifasicular block)

Answer 5

Abnormal Intraventricular Conduction

Question 6

What will tell you quickly if Axis is normal?

Answer 6

Lead 1 and aVF are positive

Question 7

What are the charicteristics of Left anterior fasicular blocks? LAFB

Answer 7

Right axis -45 DEGREES
Small Q in 1, aVL, small R in II, III, aVF
Normal QRS
Increased QRS voltage in limb leads

Question 8

What are the charicteristics of Left posterior fasicular blocks? LAFB

Answer 8

Right axis +120 or more
Small R in 1, aVL, small Q in II, III, aVF
Normal QRS
Increased QRS voltage in limb leads
No RVH

Question 9

What is a bi-fasicular block?

Answer 9

.

Question 10

what is a charicteristic of LPFB?

Answer 10

Left deviation in absence of RVH????

Question 11

What are characterisitcs of Bifasicular Blocks?

Answer 11

LBBB
RBBB plus LAFB
RBBB plu LPFB
ECG meets diagnostic criteria for all features of each entity

Question 12

What are characterisitcs of LBBB?

Answer 12

Wide QRS
V1 has QS or rS complex
V6 shows no Q, monophasic R wave
Lead I shows monophasic R, No Q

Question 13

What is a trifasicular block?

Answer 13

Block in all three fasicles; however, Left bundle is only a partial block
Most common: RBBB, LAFB, 1st degree AV block

Question 14

What is a complete block in all Fasicles called?

Answer 14

3rd degree AV block

needs a pacemaker

Question 15

What are the steps of analysis of Abnormal IV conduction?

Answer 15

D: BBB prolong the QRS (fasc blocks do not
A: LBBB increase QRS amplitude, RBBB doesn’t
M: BBB have opposite effects on QRS
V: LBBBoften causes L axis, so does LAFB
LAFB - R axi, RBBB varies

Question 16

What are the symptom of 2nd degree AV block

Answer 16

One or more atrial impulses fail to reach the ventricles, with no prematurity.
Occurrs in the AV node
See a lengthening PR interval, then a P wave with NO QRS!
Caused by impulse coming while myocardium is still refractory.

Question 17

What Pathology is Vagotonia Associated with?

Answer 17

2nd degree AV Block.

Question 18

What is unique about a 2nd degree AV block type 2?

Answer 18

Occurrs in the Purkinjie system
almost always preceded by BBB pattern
PR interval does not lengthen before AV conduction is lost.
Progresses to complete 3rd degree AV block

Question 19

What is the Tx for a Type 2 Second degree AV block?

Answer 19

Pacemaker`

Question 20

What is a third degree AV block?

Answer 20

No atrial impulses reach the ventricles.
Eq to bilateral BBB
Clinical consequences depend on the presence/absence and adequacy of escape rhythms

Question 21

What is seen on ECG in 3rd degree AV block?

Answer 21

P waves dont seem associated with the Ventricles at all!

Question 22

What is AV Dissociation?

Answer 22

Presence of independent atrial and ventricular rhythms. Competing Rhythms

Question 23

What are the causes of AV dissociation?

Answer 23

Acceleration of subsidiary pacing site
Dec. sinus node automaticity
Reentrant ventricular tachycardias.

Question 24

What is the difference between 3rd degree AV block and AV dissociation?

Answer 24

3rd Deg. AV block: Atria are going faster than the Ventricles
AV dissociation: Atria and ventricles are going at a very similar rate