EKG conduction blocks pt 2 highlights

Question 1

BBB Dx by looking at what 3 things?

Answer 1

Width, axis, & configuration of QRS complexes

Question 2

List the main characteristics of right BBB

Answer 2

1) RBBB
2) Wide QRS complex
3) RSR’ V1 and 2 (or just tall R waves)
4) Left lateral leads with late deep S wave

Question 3

List the main characteristics of left BBB

Answer 3

1) Broad or notched R wave in left lateral leads
2) Deep S wave in leads over RV
3) May see Left Axis deviation

Question 4

Abnormality of repolarization in ______ results in depressed ST segments and flipped T waves

Answer 4

BBB

Question 5

List the criteria for right and left BBBs

Answer 5

Question 6

RBBB precludes the Dx of ________

Answer 6

RVH

Question 7

LBBB ______________ the Dx of LVH

Answer 7

precludes

Question 8

True or false: Both the left anterior and left posterior fascicles are common and important

Answer 8

True

Question 9

List 3 main characteristics of hemiblocks

Answer 9

1) Cause axis deviation
2) Do Not prolong QRS complex
3) Right & Left BBB do prolong QRS

Question 10

What does a left anterior hemiblock lead to?

Answer 10

Axis is now superior and left = LAD

Question 11

What is the major effect of hemiblocks on an EKG?

Answer 11

Cause axis deviation

Question 12

What does left posterior hemiblock lead to?

Answer 12

RAD

Question 13

Left ____________ hemiblock is more common, may be seen in normal and diseased hearts

Answer 13

anterior

Question 14

Left ____________ hemiblocks almost always pathologic

Answer 14

posterior

Question 15

Give the tl;dr of hemiblocks

Answer 15

1) Shift axis
2) Do Not prolong QRS
3) No repole ST or T wave changes
4) Left posterior is worse than anterior

Question 16

List 3 causes of LAD

Answer 16

1) Left anterior hemiblock
2) LBBB (prolonged QRS, R waves prolonged in lat leads)
3) LVH

Question 17

List the criteria for hemiblocks

Answer 17

Question 18

Define bifascicular block

Answer 18

RBBB + either left anterior or posterior hemiblock