18. Normal ECG Flashcards
what direction does a normal vector point for electrical cardiac activity
from upper right to lower left
how is the p wave normally represented in aVR
inverted
where is the p-wave normally upright
lead 1, 2, V4-V6, aVF
how long is a normal PR interval & what does it represent
0.12 - 0.2 secs ==> time from SA node to ventricular M
(anything greater = anomaly)
what is the timing for a normal QRS complex
0.05 - 0.1 sec
what does a normal Q wave look like
narrow/small
1-2 mm in lead 1, aVL, aVF, V5-6
what is indicated by a QRS complex > 0.12 secs long
bundle branch block
what does a normal ST segment look like
isoelectric (around baseline)
no more than 1 mm elevated in standard lead & 2 mm in chest lead
no more than 1/2 mm depression
what does a ST depression show
subendocardial injury/ischemia
what does a ST elevation show
subepicardial or transmural injury/ischemia
where is a T wave normally upright
leads 1, 2, V3-V6
how is the T wave represented in aVR
inverted
what is the shape of a T wave
slightly round, asymmetrical
height = no more than 5 mm in standard lead and 10 mm in precordial leads
what can a tall upright or inverted T wave show
ischemic pattern
hyperkalemia (tall upright esp)
ST elevation shows patterns of..
injury
abnormal Q wave or QS complex shows-
pattern of necrosis or infarcation
what is the pattern for counting HR?
every large box count down - 300, 150, 100, 75, 50
how do you find the axis on an EKG
- look at lead 1 and aVF - are they both up? if so = normal
- find smalled deflection
- look at lead that is perpendicular to the deflection
- axis = direction perpendicular lead is pointing
how is P-mitrale represented on an ekg
broad, wide, notched
what is indicated by a tall pointed P wave
P-pulmonale
if a p wave is inverted –>
signs of AV jxnal rhythm
prolonged PR intervals can be signs of–
AV block (coronary disease, rheumatic disease, etc)
hyperthyroidism
normal variation
a shortened PR interval is indicitave of–
AV jxnal or low atrial rhythm
Wolff-parkinson-white syndrome
lown-ganong-levine syndrome
glycogen storage
htn
normal variant
what can this indicated
bundle branch block
a large Q wave can be a sign of –
an infarction
ST elevation from myocardial injury (acute/infarction)
=ST “fireman’s hat”
a tall T wave can be indicative of…
myocardial ischemia in pt w/ angina but w/o infarction
or inferior infarction (tall upright)
a deep inverted symetrical T wave can be a result of -
anterior infarction
what are signs of a normal sinus rhythm
P wave before each QRS complex
PR interval < 0.2 sec
QRS < 0.12 sec
HR > ______ = tachycardia
> 100
HR less than 60 =
bradycardia
is P waves follow QRS, what may be the rhythm
SVT (AV nodal re-entry tachycardia)
jxnal rhythm
what rhythm may be present if no P waves are present
A-fib,
atrial flutter,
jxnal/ventricular escape rhythms,
jxnal tachycardia,
VT
what are problems seen with L axis deviation
LV hypertrophy
L bundle branch block
Heart attack
precnancy, ascites, abdominal tumor
what are problems seen with R axis deviation
lung disease
RV hypertrophy
R bundle branch block
if an ekg shows lead 1 and aVF to be positive, the axis is-
normal
0-90
how are the leads represented in a L axis deviation
lead 1 = +
aVF = -
(0 to -90)
if lead 1 is neg & aVF is pos, then what axis do you have
right axis
90-180
