ecg Flashcards
what plane is the precordial aka chest leads in
transverse plane
what plane is the six limb lead in
frontal plane
Lead 1 and avL
high lateral wall LV
II and III and AVF
inferior wall of LV
AVR
looks toward RA
V1 and V2
anterior and septal
V3 and V4
anterior view of LV
V4-V6
lateral view of LV
how long is a regular p wave
.06-.12
how long is the PRI
3-5 boxes aka .12-.20
how long is the QRS
1-2.5 boxes
.04-.10
order of the av node
atrial depolarization atrial systole ventricular depolarization & atrial repolarization ventricular diastole ventricular repolarization
what does sinus bradycardia look like
everything normal except HR less than 60
Causes of bradycardia (4)
training
beta blockers
decreased automaticity of SA node
Vagal response (suctioning, ICH)
Symptoms of bradycardia
pacemaker atropine syncope dizzy angina diaphoresis
what is sinus tachycardia
everything normal except HR is more than 100
Causes of sinus tachycardia
increased sympathetic NS pain exercise emotion caffeine cigarettes amphetamines fever infection
what is sinus dysrhythmia
P- normal
QRS- normal
RR- VARIES MORE THAN ONE SMALL BOX
rate: 40-100
Causes of sinus dysrhythmia
infection
digoxin toxicity
fever
sinus dysrthymia affect on HR and inspiration/expiration
HR increases with inspiration
HR decreases with expiration
Wandering atrial pacemaker
impulses arise from areas other than SA node
P- vary in appearance
RR intervals vary
HR <100
PT implications for wandering atrial pacemaker
ischemia
injury to SA node (right coronary artery)
can progress to A fib
Premature atrial complex
ectopic focus initiates impulse
P wave of early beat has a different appearance
PT implications of premature atrial complex
emotional distress caffeine nicotine alcohol MI can progress to a-fib
A flutter
repeated atrial depolarization from one foci
repeated firing
P waves: sawtooth pattern
more than one P wave before QRS
RR interval vary
HR- 250-350
what does the AV node do in A flutter
AV node blocks some impulses from being conducted to ventricles
What causes A flutter
beta blockers
cardioversion
PT implications for A flutter
mitral valve disease CAD MI stress hypoxemia pericarditis
A fib
quivering of atria due to MULTIPLE ectopic foci
P waves absent (wavy baseline)
RR irregular
causes of A fib
old age CHF MI digoxin toxicity drug use (heroine) stress
controlled A fib
HR <100
little impact on CO
Uncontrolled a fib
HR >100
impact on CO
Symptoms of A fib
dizzy/light headed
diaphoresis
palpitations
A fib characteristics
turbulent blood flow: likes to clot: high risk of stroke
anti-arrthymic meds
cardioversion
Junctional Rhythm
Av junction becomes primary pacemaker
aka ESCAPE rhythm
NO P wave
rate: 40-60 (intrinsic rate of AV node)
Causes/ symptoms of Junctional Rhythm
SA pathology increased vagal tone digoxin toxicity MI drop in CO
atropine
pacemaker
1st degree heart block
impulse begins in SA node
impulse delayed on the way to AV node or AV conduction time is prolonged
PRI is PROLONGED
HR may be slow
causes of 1st degree heart block
CAD
infarction
beta blockers
2nd degree AV block type 1
-wekenbach or mobitz 1
progressive prolongation of PRI until 1 impulse doesnt get through
p wave before every QRS until P STANDS ALONE (conduction blocked)
RR irregular
RARELY PROGRESSES TO OTHER BLOCKS
2nd degree type 1 block seen with
RCA disease/infarction
beta blockers
2nd degree type 2 block
blocked conduction of one impulse to ventricles
RR interval varies
no change in PRI
more than one P stands alone
2nd degree type 2 block characteristics
MI (LAD)
infarction of AV node (RCA)
digoxin toxicity
drop in CO
pacemaker
atropine
can progress to complete heart block
3rd degree AV block
-complete heart block
no impulses from above the ventricle are conducted through AV node
NO communication between atria & ventricles
P waves have NO relation to QRS
QRS is WIDE
HR- 30-50
characteristics of complete heart block
MI
dioxin toxicity
drop in CO (dizzy, SOB, chest pain, diaphoresis)
permanent pacemaker
atropine
MEDICAL emergency
Premature ventricular complex
ectopic focus from a ventricle
ventricular depolarization occurs before SA node fires
QRS is WIDE
no P wave
followed by compensatory pause
bigeminey
every other beat is a PVC
trigeminy
every 3rd beat is a PVC
couplet
2 PVCs paired together
triplet
3 PVCs in a row
unifocal
if PVCs appear the same
multifocal
if PVCs appear different
Causes of PVC
caffeine nicotine stress overexertion hypo/hyperkalemia ischemia cardiomyopathy cardiac irritation
characteristics of PVC
increased frequency of PVCs leads to
- decreased filling time
- decreased preload
- decreased SV
drop in CO
may progress to V tach or V fib
PVC is more dangerous when
couplets multifocal more than 6 a minute triplets anti-arrthymia
Ventricular tachycardia
V-tach
3 or more PVCs in a row
absent P wave
wide QRS
V rate: 100-250
V tach characteristics
ischemia/infarction CAD HTN Digoxin electrolyte imbalance
CO GREATLY AFFECTED
light head, syncope, chest pain
weak pulse
disorientation
cardioverion, defib, pharm therapy
torsades de pointes
twists around isoelectric line
occurs during v tach
significant drop in CO
ventricular fibrillation
quivering of ventricles
multiple ectopic foci = no synchronous contraction
NO CO
zig zag
progression of v tach
V fib comes from:
infarction
ischemia
MI
digoxin toxicity
V fib needs:
defibrillation
oxygen
CPR
cardiac meds
MI
altered electrical conduction during angina
t wave inversion
t wave flat or peak
ST segment: elevate or depressed at least 1 mm
MI zone of ischemia
T wave inversion of flattening
MI zone of infarction
Q wave: transmural MI
Non Q wave: sub endocardial
bundle branch blocks
MI: transmural
Q wave
all 3 layers affected
more than .04 sec in duration
at least one quarter the height of R wave
MI: subendocardial
non Q wave
inner half of myocardium
more likely to re-infarct
location of ischemia/infarction
V1, V2, V3, V4
anterior left ventricle
location of ischemia/infarction
V1, V2
septal infarction
location of ischemia/infarction
II, III, AVF
inferior infarction, RCA
location of ischemia/infarction
I, avL
lateral infarction
circumflex artery
A fib
goals of therapy
Control ventricular rate: block AV node
Convert a fib or flutter to NSR
How do you control rate of a fib
Beta blockers
CCBAs
Digoxin
How to convert a fib to NSR
Amiodarone
Ventricular arrhythmia
Goals of chronic therapy
Treat underlying condition
Prevent v fib
Reduce PVCs
Ventricular arrhythmia
Common meds
Beta blockers Amiodarone Flecanide Quinidine Procainamaide
Pacemaker
Estim of myocardium to depolarize
Appears as vertical line on ecg
