what is the path of the cardiac conduction system
SA node to internodal atrial pathways to AV node to AV junction to AV node to Bundle of His to r and l bundle branch to purkinje fibers
which limb always has a positive electrode at all times
left foot
except in its own lead, what limb lead is always negative electrode
right hand
where do all the limb leads project
down to the left leg
if the ECG lead (negative to positive) is in the parallel direciton of current what does the ECG read
sharp upstroke
if the ECG lead (negative to positive) is in the oblique direction of current what does the ECG read
blunter upstroke
if the ECG lead (negative to positive) is in the perpendicular direction of current what does the ECG read
no deflection
if the ECG lead (negative to positive) is in the opposite direciton of the current what does the ECG read
sharp downward deflection
if the ECG lead (negative to positive) is in the oblique opposite direction of the current what does the ECG read
blunter downward deflection
if there is no current flow what does the ECG read
0
where does PR segment go from
end of P to beginning of Q
where does the PR interval go from
beginning of P to beginning of Q (includes P wave)
where does the QRS interval go from
beginning of Q to end of S
where does teh ST segment go from
end of S to beginning of T
how much time are the small boxes on the ECG
0.04 seconds apiece
how much time are the larger segments on the ECG
0.2 seconds
what is the P wave synonymous with
atrial excitation
what is signified by the PR interval
impulse delay at AV juction
what is the QRS complex
electrical excitation of the ventricles
what is the T wave
ventricular repolarization
what are the pulseless rhythms
v tach
v fib
asystole
what is this rhythm
v tach
what is v tach charaterized by
wide complex
regular
fast
no P waves
what is this rhythm
v fib
what characterizes v fib
irregular and disorganized ventricular activity
discrete QRS complexes not observed
what is asystole
flat line
what are the types of tachyarrythmia
supraventricular tachycardia
atrial fib
atrial flutter
what rhythm is this
supraventricular tachycardia
is the SVT complex wide or narrow
narrow
is SVT regular or irregular
regular
is SVT fast or slow
fast
are there visible P waves in SVT
no
how are AV nodal reentrant tachycardisa terminated acutely
vagal manuevers or adenosine
what is this rhythm
atrial fibrillation
how is atrial fibrillation often desribed
"irregularly irregular"
are there visible P waves in a fib
no
where does baseline go in a fib
everywhere
what rhythm is this
atrial flutter
what is the classic pattern of atrial flutter
sawtooth
is atrial flutter regular or irregular
can be either
what are the brady arrythmias
sinus bradycardia
2,d degree AV block type I (Wenckebach/Mobit I)
2nd degree AV block type II
3rd degree AV block/complete heart block
what are the PP intervals like in 2nd degree type I
regular
what are the PR intervales like in 2nd degree type I
progressively prolongs until dropped
what is characteristic of the QRSs in 2nd degree type I
grouped
what is this
2nd degree AV block type I
what is this
2nd degree AV block type I
what happens to PR interval in 2nd degree blok type II
remains contant until dropped or nonconducted beat
is there suggestion or other evidence for conduction block system disaese in 2nd degree AV block type II
yes like BBB or 1st degree AV block
what is this
2nd degree block type II
what is t his
3rd degree AV block
does complete AV block onset quickly
acute (syncope) or vague (fatigue, dyspnea, dementia)
what does complete AV block ECG show
regular but dissociated atrial and vetnrciular activity
when does complete heart block with narrow jucntional escape often occur
acute inferior MI
what is this rhythm
sinus rhythm
what is this rhythm
fine vfib
what is this rhythm
sinus tachy
what is this rhythm
a fib?
what is this rhythm
SVT
what is this rhythm
type 1 2nd degree block
what is this rhythm
type 2 2nd degree block
what is this rhythm
type 1 2nd degree block
what is a junctional rhythm
an abnormal heart rhythm resulting from impulses coming from a locus of tissue in the area of the atrioventricular node,the "junction" between atria and ventricles.
what is this rhythm
fine v fib
what is first degree AV block
when PR interval is lengthened beyond 0.2 seconds
what are the bipolar ECG leads
leads I, II, and III
what are the unipolar ECG leads
aVR, aVL, aVF
what are the precordial ECG leads
V1-V6
what leads form the einthoven's triangle
leads I through III
what are the unipolar or augmented limb leads
aVR, VL, VF
what are the lateral leads
I, aVL, V5, V6
what are the inferior leads
II, III, aVF
what are the septal leads
V1, V2
what are the anterior leads
V3, V4
what should we think about with ECG's
speed
amplitude and deflection
calibration
how long is the PR interval usually
120-200 msec
how long is the QRS interval usually
80-120 msec
how long is the QT interval usually
330-420 msec
what are the iimportant time intervals in the ECG (one segment, three intervals)
PR int
QRS int
ST seg
QT int
what is the 4 step analysis for ECG
rate
rhythm
axis
morphologies
what is the stepwise analysis of the morphology of an ECG (wave, complex, 2 intervals and a segment)
P wave
PR interval
QRS complex
ST segment
QT interval
what's the triplicate method for HR determination
300, 150, 100
75, 60, 50
43, 38
what are the rhythms possible
regular
occasionally irregular
regularly irregular
irregularly irregular
what is axis determination quickly done by
looking at lead I and II
what does RAD look like in lead I and II
lead I negative with positive lead II
what does LAD look like in lead I and II
lead I positive with negative lead II
how should progression of P wave evaluation flow
present
regularity
size
P and QRS
upright or inverted
do they all look alike
what should be assessed with P waves present rhythms?
sinus or junctional rhtyhm
what types of things could be possible in P wave regularity
PAC
sinus arrest
what could change P wave size
RA or LA enlargement
if there is not one P wave for each QRS what will this be called
AV block
if P wavss are inverted what could this signal
sinus rhythm/ectopic atrial rhythm
if P waves don't all look alike, what could this signal
multifocal atrial tachycardia
what would an abnormal PR interval indicate
1st degree AV block or type I 2nd degree AV block
what would an abnormal QRS duration indicate
BBB
IVCD
what could ST segment depression indicate
ischemia/hypertrophy
what could ST segment elevation indicate
injury/pericarditis/early repol/aneurysm/prinzmetal's angina