ECG Flashcards
Describe a brief approach to ECGs
- check calibration
- check rhythm
- normal sinus
- sinus tachy
- regularly irregular
- irregularly irregular - check rate
- 300-150-100-75-60-50 - intervals
- PR 3-5 small boxes
- QRS less than 2.5 small boxes
- QT less than 1/2 the R-R interval if HR normal - axis
- look at I, II and AVF - p wave abnormalities
- look at II and V1 for LA or RA enlargement - QRS abnormalities
- LVH, RVH, bundle branch blocks or pathologic Q waves - ST segment or T wave abnormalities
- ST elevation, ST depression, T wave inversion - compare with previous ECGs
define normal sinus rhythm
every p wave is followed by a QRS
every QRS is preceded by a p wave
p waves are upright in leads I, II and III
PR interval of 3-5 small boxes
rate between 60-100 bpm
how long does each small box represent
0.04 s (4ms)
name the atrial arrhythmias
(tachy)
atrial premature beats
atrial flutter
atrial fibrillation
paroxysmal SVTs
focal atrial tachy
multifocal atrial tachy
name the AV node arrhythmias
brady:
conduction blocks
junctional escape rhythms
tachy:
AVRT
AVNRT
name the ventricular arrhythmias
brady:
ventricular escape rhythm
tachy: ventricular premature beats ventricular tachycardia torsades ventricular fibrillation
how do you identify an escape rhythm
no p waves before QRS
narrow QRS–> junctional
wide QRS–> ventricular
define 1st degree AV block
1 to 1 p to QRS ratio
long PR interval (more than 5 small boxes)
define second degree heart block
intermittent failure of AV conduction and so some p waves dont have a QRS after
two types–
Type I–> gradual lengthening of the PR interval until a QRS is missed and then the cycle starts over
Type II–> sudden loss of AV conduction so random QRS are missed
define 3rd degree/complete heart block
disconnects the atria from the ventricles so atria are controlled by the SA node and the ventricles by a distal escape rhythm
what is atrial flutter
rapid REGULAR atrial activity
how do you identify atrial flutter
sawtooth waves
rate is 180-350
what is atrial fibrillation
chaotic
distinct p waves are NOT discernible
random bumpy shit between QRS complexes
what is multifocal atrial tachy
IRREGULAR rhythm with multiple (more than 3) p wave morphologies
what often triggers torsades
long QTc–> can degenerate to VF
what is ventricular fibrillation
immediately life threatening
major cause of mortality in acute MI
where do you look for RVH and what do you look for
leads V1 and V2
R wave bigger than S wave and right axis deviation
how do you determine a normal axis
if QRS is upright in leads I and lead aVF–> normal
also if more positive than negative in I and II
what pattern suggest left axis deviation
upright QRS in lead I and downward in lead II
or upright QRS in lead I, downward in aVF and downward in lead II
(if upright in lead I, downward in aVF and upward in lead II–> normal)
list some conditions that cause left axis deviation
normal varient
left anterior fascicular block
LVH
LBBB
mechanical shift of heart in the chest
inferior MI
wolff parkinson white syndrome
ventricular rhythms
ostium primum ASD
what pattern suggests right axis deviation
downward QRS in lead I and positive in aVF
or downward in lead I and upward in lead II
what causes right axis deviation
normal variant
RBBB
RVH
left posterior fascicular block
dextrocardia
ventricular rhythms
lateral wall MI
WPW
acute right heart strain/pressure overload
what does the p wave indicate
atrial depolarization
occurs when the SA node creates an action potential that depolarizes the atria
where do you look to make sure the p wave is originating from the SA node
p wave should be upright in lead II
what can widen or increase the amplitude of the p wave
atrial enlargements
RA enlargement indicated by big bump then little bump in lead II
LA enlargement indicated by little bump then big bump in lead II, inverted in V1
