Intravent Conduction Defects Flashcards
Atrial enlargement appears as what on ECG?
P wave changes
Vent hypertrophy appears as what on ECG?
QRS changes
Chronic pulmonary dz causes R atrial enlargement how/why?
Requires more filling pressure to move blood thru heart -> atria enlarges to add’l blood needed to ↑ pressure
Mirtal regurge causes L atrial enlargement how/why?
Blood forced backward into atria -> enlarges to accommodate ↑ blood volume
Which leads assess atrial enlargement?
II and V1
R atrial enlargement seen as what on ECG?
Tall P wave in II, III, aVF
Biphase P wave (taller than deep) in V1
L atrial enlargement seen as what on ECG?
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
Vent hypertrophy (C) caused by?
HTN
Vent hypertrophy affects electrical activity how?
Required more electrical activity to depol the enlarged tissue.
R vent hypertrophy seen as what on ECG?
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)
L vent hypertrophy appears as what on ECG?
LAD
R wave taller and S wave smaller in leads over LV (V5-6)
S wave taller in leads over RV (V1-2)
HIS bundle branch divisions?
Right fibers
Left -> septal, anterior and posterior fascicles
BBB is what?
failure of bundle branch to conduct impulse
causes delay in depol of vent
BBB appears as what on ECG?
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
Incomplete BBB is?
Seen w/ vent hypertrophy.
QRS is wide and mimics BBB.
RBBB appears as what on ECG?
Wide QRS, leads V1-2
M-shaped RR’, lead V1
Wide S wave, lead V6
No axis deviation
Causes of RBBB?
CAD
PE
LBBB appears as what on ECG?
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
BBB w/ LVH or RVH diagnostics?
CAN”T dx LVH w/ LBBB or RVH w/ RBBB
Hemiblock is?
Block of either Anterior or Posterior Fascicle of LBB
Hemiblock appears as what on ECG?
∆ in QRS axis w/o ∆ in QRS duration
L Anterior Hemi (LAHB) appers as what on ECG?
LAD (-45° to -90°)
Tall R waves, lead I
Deep S wave, aVF
Normal QRS duration
L Posterior Hemi (LPHB) appears as what on ECG?
RAD (>= +120° to +180°)
Normal QRS duration
r/o other causes of RAD (cor pulm, pulm HTN)
Bifascicular Block is?
RBBB + LAHB or LPHB
Bifascicular Block appears as what on ECG?
RBBB plus frontal plane axis deviation
+ LAHB (LAD)
+ LPHB (RAD)
Preexcitation Syndromes are?
Accessory pathways b/w atria and vents:
Bundle of Kent (WPW)
James Fibers (LGL)
Bypass the AV node and HIS -> early depol of vents
Preexcitation Syndromes appear as what on ECG?
short PR interval
Wolff-Parkinson-White Synd is?
Impluse from SA node travels thru Kent in RA instead of AV/HIS -> preexcitiation/early depol of vent
WPW appears as what on ECG?
Short PR interval
DELTA wave
Lown-Ganong-Levine Synd is?
Impluse from SA node travels thru James in RA instead of AV/HIS -> preexcitiation/early depol of vent
LGL appears as what on ECG?
Short PR interval
No delta waves
Normal QRS
