Intravent Conduction Defects

Question 1

Atrial enlargement appears as what on ECG?

Answer 1

P wave changes

Question 2

Vent hypertrophy appears as what on ECG?

Answer 2

QRS changes

Question 3

Chronic pulmonary dz causes R atrial enlargement how/why?

Answer 3

Requires more filling pressure to move blood thru heart -> atria enlarges to add’l blood needed to ↑ pressure

Question 4

Mirtal regurge causes L atrial enlargement how/why?

Answer 4

Blood forced backward into atria -> enlarges to accommodate ↑ blood volume

Question 5

Which leads assess atrial enlargement?

Answer 5

II and V1

Question 6

R atrial enlargement seen as what on ECG?

Answer 6

Tall P wave in II, III, aVF

Biphase P wave (taller than deep) in V1

Question 7

L atrial enlargement seen as what on ECG?

Answer 7

Broad P wave

Notched P wave (P mitral), end of wave taller than start: I, II, V4-V6

Biphasic P wave (deeper than tall) in V1-V2

Question 8

Vent hypertrophy (C) caused by?

Answer 8

HTN

Question 9

Vent hypertrophy affects electrical activity how?

Answer 9

Required more electrical activity to depol the enlarged tissue.

Question 10

R vent hypertrophy seen as what on ECG?

Answer 10

RAD

R waves tall in V1 and become less tall as progress to V6

(normal heart starts neg at V1 and becomes tall as progresses to V6)

Question 11

L vent hypertrophy appears as what on ECG?

Answer 11

LAD

R wave taller and S wave smaller in leads over LV (V5-6)

S wave taller in leads over RV (V1-2)

Question 12

HIS bundle branch divisions?

Answer 12

Right fibers

Left -> septal, anterior and posterior fascicles

Question 13

BBB is what?

Answer 13

failure of bundle branch to conduct impulse

causes delay in depol of vent

Question 14

BBB appears as what on ECG?

Answer 14

Wide QRS >= 0.12 sec

RR’ (rabbit ears, M-shaped R wave) in V leads

Vents contract at different times, thus the 2 R waves

Question 15

Incomplete BBB is?

Answer 15

Seen w/ vent hypertrophy.

QRS is wide and mimics BBB.

Question 16

RBBB appears as what on ECG?

Answer 16

Wide QRS, leads V1-2

M-shaped RR’, lead V1

Wide S wave, lead V6

No axis deviation

Question 17

Causes of RBBB?

Answer 17

CAD

PE

Question 18

LBBB appears as what on ECG?

Answer 18

Wide QRS

Wide R wave, leads I and V6

R waves (P) notched or flat tops, V5-6

S waves opposite, broad or deep, V1-2

Question 19

BBB w/ LVH or RVH diagnostics?

Answer 19

CAN”T dx LVH w/ LBBB or RVH w/ RBBB

Question 20

Hemiblock is?

Answer 20

Block of either Anterior or Posterior Fascicle of LBB

Question 21

Hemiblock appears as what on ECG?

Answer 21

∆ in QRS axis w/o ∆ in QRS duration

Question 22

L Anterior Hemi (LAHB) appers as what on ECG?

Answer 22

LAD (-45° to -90°)

Tall R waves, lead I

Deep S wave, aVF

Normal QRS duration

Question 23

L Posterior Hemi (LPHB) appears as what on ECG?

Answer 23

RAD (>= +120° to +180°)

Normal QRS duration

r/o other causes of RAD (cor pulm, pulm HTN)

Question 24

Bifascicular Block is?

Answer 24

RBBB + LAHB or LPHB

Question 25

Bifascicular Block appears as what on ECG?

Answer 25

RBBB plus frontal plane axis deviation

+ LAHB (LAD)
+ LPHB (RAD)

Question 26

Preexcitation Syndromes are?

Answer 26

Accessory pathways b/w atria and vents:
Bundle of Kent (WPW)
James Fibers (LGL)

Bypass the AV node and HIS -> early depol of vents

Question 27

Preexcitation Syndromes appear as what on ECG?

Answer 27

short PR interval

Question 28

Wolff-Parkinson-White Synd is?

Answer 28

Impluse from SA node travels thru Kent in RA instead of AV/HIS -> preexcitiation/early depol of vent

Question 29

WPW appears as what on ECG?

Answer 29

Short PR interval

DELTA wave

Question 30

Lown-Ganong-Levine Synd is?

Answer 30

Impluse from SA node travels thru James in RA instead of AV/HIS -> preexcitiation/early depol of vent

Question 31

LGL appears as what on ECG?

Answer 31

Short PR interval

No delta waves

Normal QRS