ECG Flashcards
significance of axis deviation include: RAD could signify _____________ while LAD could signify ___________.
pulmonary embolism; conduction defect
pulmonary conditions and congenital heart problems cause:
a. right ventricular hypertrophy
b. left ventricular hypertrophy
a. right ventricular hypertrophy
which interval signifies time taken for conduction to travel from SA node to ventricles?
PR interval
interferance with normal conduction of depolarization leads to
heart block
If depolarization originates in SA node and reaches ventricles but there is a delay in the conduction somewhere. this is known as _____________ characterized by prolonged _______.
first degree heart block. characterized by prolonged PR interval. PR>5 small squares
when one or more conductions fail to reach the ventricles. this is known as ______________ heart block
second degree
progressive lengthening of PR interval then 1 P wave with no proceeding QRS
second degree heart block. MOBITZ type 1.
Usually benign and asymptomatic
also known as wenkebach.
# of QRS waves= # of P waves-1
constant PR interval with occasional drop of QRS is known as
second degree heart block MOBITZ type 2
which is more common type of second degree heart block? which is more dangerous? why?…
a/MOBITZ 1
b/MOBITZ 2
MOBITZ 1 is more common but MOBITZ 2 is more dangerous as it carries risk of becoming third degree heart block or cardiac arrest
normal contraction from atria but no conduction to ventricles. complete heart block. P wave and QRS disassociation. these are known as
third degree heart block.
high risk of cardiac arrest! needs pacemaker(mobitz 2 needs pacemaker as well)
there is an escape rhythm in which type of heart block?
third degree.
the QRS complexes are also abnormally shaped as there is abnormal spread of depolarization from a ventricular focus.
causes of third degree heart block?
most common: fibrosis around bundle of His
Acutely: due to MI
could also be caused by block of both bundle branches
time taken for depolarization to spread from interventricular septum to furthest parts of ventricles is the
QRS complex
QRS is considered prolonged if it is more than ________ squares. What are the two conditions causing prolonged QRS?
three small squares.
- Bundle branch blocks
- Depolarization beginning in ventricles
if QRS is prolonged and the rhythm is
- sinus(P wave present and normal PR)
- not sinus
- bundle branch block
2. depolarization beginning in ventricles
which bundle branch block PATTERN (normal QRS duration) could be present in normal people? what does this same one indicate if QRS is prolonged?
right. problem with right side of the heart.
NOTE: left never happens in healthy ppl. always indicates heart disease(usually left ventricle.)
which BBB is associated with inverted T wave
left. the inversion is usually seen in the lateral leads.
NOTE: BBB are important to point out soon since they make interpretation of the ECG hard
which BBB is best seen on V1 vs V6?
V1:right
V6: left
how to recognize LBBB?
M(widened and notched QRS) pattern on V6. this could also appear on other leads like 1,2,V5
NOTE: W is hardly seen on V1; it is sinus! t inversion could be present.
which type of heart block(1,2,3) ALWAYS indicated a conducting tissue disease? is it more often fibrotic or ischemic
type 3. often fibrotic
need pacemaker
think about an atrial septal defect with ________ bundle branch block
right. it has no specific treatment
think about aortic stenosis with _BBB
left bundle branch block
think about ischemic disease with _BBB
left bundle branch block
patient has recently had severe chest pain. what could LBBB indicate?
acute myocardial infarction
think about left ventricular hypertrophy and its causes with
left axis deviation
what could left axis deviation and right bundle branch block indicate?
severe conducting tissue disease. pacemaker is needed if symptoms suggest intermittent complete heartblock
Changes in sinus rhythm seen in younger ppl due to respiration is called
sinus arrhythmia
QRS in supraventricular arrhythmia is ________ while in ventricular it is _________.
normal(narrow). abnormal(wide and abnormal shape) t wave is also abnormal in the latter one
frequencies of depolarization:
SA:
atrial/nodal:
ventricular:
70 bpm. 50. 30
if p wave is present but abnormal in an escape beat, this is
atrial escape?
which escape beat happens in complete heart block?
ventricular. there are multiple p waves and then an abnormal QRS complex with an abnormal t wave
atropine is a positive or negative? ionotrope or chronotrope?
positive chronotrope(increases heart rate)
which type of escape beat happens in third degree heart block?
ventricular.
atrial rate of >250/min is called
atrial flutter. there is no flat baseline between the p waves and often called sawtooth
narrow complex tachycardia of 125-150/min and atrial flutter should make u think of
2:1 block.
QRS rate is irregular in..
a. atrial flutter
b. atrial fibrillation
b
QRS is wide and abnormal in which type of tachycardia?
ventricular..usually t waves disappear in tachycardias
wide complex tachycardia is treated by _________ while narrow complex is treated by _______.
lidocaine. adenosine
peaked P wave:
broad and bifid p wave:
- right atrial hypertrophy
2. left atrial hypertrophy
what can right atrial hypertrophy indicate? 2 things
- tricuspid valve stenosis
2. pulmonary hypertension
what can left atrial hypertrophy indicate/
mitral valve stenosis
when V1 becomes upright, (R>S), this indicates
right ventricular hypertrophy. S becomes deep on V6
if ECG of a person suspected of pulmonary embolism shows normal pattern, what is the approach?
give anti coagulant. do not ignore it
what to look for in pulmonary embolism regarding the following:
- p wave
- axis
- V1
- V6
- transition point on chest leads
- Q wave
- peaked p wave(atrial hypertrophy)
- right axis deviation: deep S on lead 1
- tall R in V1
- persistent and deep S in lead V6
- transition point shift to the left(v5,v5)
- Q wave appears in lead III: resembling inferior infarction
can there be pulmonary embolism without any wave abnormalities?
yes. patient could present with only sinus tachycardia
what changes are expected to be found in V1 and V6 in left ventricular hypertrophy? are these changes enough to diagnose LVH?
V1: deep S wave(also in V2)
V6: tall R wave. (also in V5)
NO…
what 2 changes are associated with significant LVH?
- left axis deviation(lead II)
2. inverted t wave in the left leads: II,VL,V5,V6
When is an ST segment elevation seen? 2 occasions.
seen in acute MYOCARDIAL injury
- infarction
- pericarditis
note: with the former, the specific leads show which part is infarcted, with pericarditis most leads will show ST elevation since pericarditis is not focal.
when is a horizontal ST segment depression seen? what about sloped depression?
- ischemia(there will be upright T wave) and exercise
2. sloping is the characteristic effect of digoxin, a drug given for atrial fibrillation, flutter, and heart failure
which leads have a normal inverted t wave?
VR, V1. maybe III and V2. V3 in some black people
count the conditions that can cause inverted t wave. (almost everything)
- ischemia
- BBB
- ventricular hypertrophy
- digoxin effect
- normal
what is the first abnormality seen after an MI? what changed follow?
ST segment elevation. this returns back to normal in 24-48 hrs. Q wave appearance and t wave inversion. these don’t return to normal
if an infarction is not full thickness, it doesn’t produce a window thus there is no _ wave. however what change is still prominent? what is this type of infarction called?
q wave. t wave inversion will still happen. this is called a NSTEMI or subendothelial infarction.
t wave inversion, sloping ST depression, narrow QRS is seen in
digoxin effect
which plasma electrolyte level doesn’t affect the ECG out of the 4 main ones?
Sodium unlike potassium, calcium, magnesium.
high levels of potassium and magnesium show as
PEAKED T WAVE with ST disappearance. maybe prolonged QRS.
low levels of potassium and magnesium show as
flat t wave with appearance of a small hump at the end of ‘t wave’ called a u wave
high levels of calcium show as while high levels as
short QT interval; long QT
one small square is 1 mm. in width this means _____ and in height it means _______
width: 0.04 seconds.
height: 0.1 mv
if there’s atrial fibrillation. what clue could tell us it’s due to digoxin?
sloping ST depression
in which type of extrasystole is there p wave but it is abnormal
atrial
what would an inverted p wave in most leads indicate?
an atrial focus is controlling the heart. atrial ectopic beat
tall p wave exists in normality. when is it actually significant?
tall p wave indicates right atrial hypertrophy. when there is also right ventricular hypertrophy
what does a bifid p wave in the presence of left ventricular hypertrophy indicate
mitral valve stenosis. but this is rare
RAD is often seen in healthy ppl. when is it significant?
when there is right ventricular hypertrophy. also if the patient has had Previous MI
what does RAD in a person with previous MI indicate
left posterior hemiblock
criteria for LVH include V1/V2 and V5/V6 >35 mm or 7 large squares. this is only significant if what other ecg change is seen
when there is also inverted t wave in the left lateral leads
what is the hallmark of a fully developed STEMI?
Q waves. reminder that q waves can be seen in normal individuals in the lateral and inferior leads.
