ECG IV: Abnormal intraventricular conduction Flashcards Preview

Year 2 Cardiovascular > ECG IV: Abnormal intraventricular conduction > Flashcards

Flashcards in ECG IV: Abnormal intraventricular conduction Deck (19):
1

what are the unifascicular blocks?

left unifascicular block
RBBB

2

what are the left unifascicular blocks?

LAFB
LPFB

3

what are the bifascicular blocks?

LBBB
right bundle plus LAFB
right bundle plus LPFB

4

what are the requirements for normal QRS and T waves?

normal RV and LV chamber sizes
normal myocardial perfusion
normal rapid impulse conduction
normal activation sequence (no pre-excitation)

5

what events occur in bundle branch blocks?

one ventricle activates first; other side is activated by impulses spreading from the first
QRS duration is therefore prolonged (wider QRS)

6

what is the resulting QRS appearance in a bundle branch block? why?

resembles a ventricular premature or paced beat

impulse propagation via muscle, not special conduction tissue

7

which bundle branch block has a worse prognosis?

LBBB

8

broad QS in V1 and broad, slurred R wave in V6 is indicative of what condition?

LBBB

9

broad QRS (more than 0.12 s) with an rSR' pattern in V1 and deep, broad S wave in V6 is indicative of what condition?

RBBB

10

what is seen on the ECG in a LBBB?

broad QS in V1 and broad, slurred R wave in V6

11

what is seen on the ECG in a RBBB?

broad QRS (more than 0.12 s) with an rSR' pattern in V1 and deep, broad S wave in V6

12

left anterior fascicular blocks (LAFBs) have what characteristics with respect to

axis
lead morphologies
QRS duration
QRS voltage

axis - left, at least -45 degrees (most important)
leads - small Q in I, avL; small R in II, III, avF
QRS duration - NORMAL
QRS voltage - increased

13

left posterior fascicular blocks (LPFBs) have what characteristics with respect to

axis
lead morphologies
QRS duration
QRS voltage

axis - right, usually +120 or more
leads - small R in I, avL; small Q in II, III, avF
QRS duration - NORMAL
QRS voltage - increased

14

is there evidence of RVH in left posterior fascicular blocks?

no

15

left bundle branch blocks (LBBBs) have what characteristics with respect to

QRS duration
lead morphologies

QRS - wide (more than 0.12 s)
V1 - QS or rS complex
V6 - no Q, monophasic R wave
lead I - monophasic R, no Q

16

what is the most common trifascicular block?

RBBB, LAFB, first degree AV block

17

trifascicular blocks require what therapy?

pacemaker

18

do fascicular blocks widen the QRS?

no

19

what are the features of abnormal intraventricular conduction with respect to

duration
amplitude
morphology
vector

duration - widened QRS
amplitude - LBBB increases QRS amplitude, RBBB does not
morphology - BBBs have opposite effects on QRS
vector - LBBB often causes L axis, so does LAFB; LPFB produces R axis, RBBB axis