BC3- Cardio - EKG Flashcards

Cardiac electrophysiology
Terms Definitions
SA Node location
base of the right atrium
SA Node
normal pacemaker of the heart
SA Node rate
60-100
How is the SA node connected to the AV node
by internodal pathways
AV Node location
apex of the right atrium
AV node rate
slows the impulse down to 40-60
What is the back-up with the SA node doesn't work?
AV
Conduction system of the heart
SA Node - AV Node - Bundle of HIS - Bundle Branches - Perkinje Fibers
Ventricle Rate
20-40
Juctional Rate
40-60
Parasympathetic
slows down
Sympathetic
fight or flight
1 small box on EKG strip =
.04 seconds
1 large box on EKG strip =
.20 seconds
15 large boxes on EKG strip =
3 seconds
P wave measures
produced as impusle from SA and AV junction - cause atrial contraction
PRI is what?
beginning of the P to the beginning of the Q wave = time between arial depolarization (contraction) and the start of ventricular conduction (depolarization)
Normal PRI
.12-.20 seconds
QRS Complex
Conduction of impulse through Bundle of HIS to Perkinje Fibers causing contraction of ventricles
Normal QRS
.04-.10 seconds
If QRS "widens" to > .10 seconds
indicates a bundle branch block
What does QTI measure
measures depolarization and repolarization
Formula for QT Interval
QT interval / sq root of R
Normal QTI
less than or equal to 0.40 seconds
How do you measure QTI
from the beginning of the Q to the end of the T
Electrolytes that may increase QTI
hypocalcemia, hypomagnesium, hypokalemia
CNS disorders that may increase QTI
stroke, subarrachnoid hemorrhage, trauma
Drugs that may increase QTI
tricyclics, phenothiazines, erythromycin, albuterol, lopressor, decongestants, diuretics, Amiodorone
Rule of Thumb for QTI
If patient is not tachycardic, the QT interval should not be more than half the R-R interval
T wave indicates
ventricular repolarization
Sinus Rhythm originates from
SA Node
Sinus Rhythm HR
60-100
Sinus Rhythm P wave for every QRS =
1:1
Sinus Rhythm PRI
.12-.20 seconds (normal)
Sinus Rhythm QRS
.04-.10 seconds (normal)
Sinus Bradycardia orginiates from
SA Node
Sinus Bradycardia HR
<60
Sinus Bradycardia P wave for every QRS =
1:1
Sinus Bradycardia PRI
.12-.20 seconds (normal)
Sinus Bradycardia QRS
.04-.10 seconds (normal)
Causes of Sinus Bradycardia
Hyperkalemia, Vagal activity increased, Digoxin (common), Late hypoxia - corrected with 02
Effects of Sinus Bradycardia
increase preload, decreased mean arterial pressure
Treatment of Sinus Bradycardia
treat cause; pacer, atropine
Sinus Tachycardia originates from
SA Node
Sinus Tachycardia HR
100-150
Sinus Tachycardia PRI
.12-.20 seconds (normal)
Sinus Tachycardia QRS
.04-.10 seconds (normal)
Sinus Tachycardia P wave for every QRS =
1:1
Causes of Sinus Tachycardia
Increase catecholamine release, hypercalcemia, fever, early symptom of hypoxia, hypovolemia, pump failure
Effects of Sinus Tachycardia
decreased filling times, decreased MAP, increased myocardial demand, increase O2 demand,
Treatment of Sinus Tachycardia
treat underlying cause, calcium channel blockers, beta blockers, bed rest, oxygen
Premature Atrial Contraction (PAC) is not _________
a rhythm
PAC originates in
an ectopic focus in either atrium appearing earlier than a P wave generated by the SA node
PAC's may be due to use of
stimulants
PAC's are often seen in what conditions
CHF, COPD, infections, medications
PAC HR
60-100
PAC P wave
has different configuration than those originating in the SA node
PAC PRI
.12-.20 seconds (normal)
PAC QRS - P ratio
each QRS has a P
Causes of PAC
Hypokalemia, digitalis toxicity, hypoxia
Treatment of PAC
treat the underlying cause
Sinus Dysrhythmia Rate
Rates vary
Sinus Dysrhythmia PRI
.12-.20 seconds (normal)
Sinus Dysrhythmia P wave for every QRS =
P wave for each QRS
Sinus Dysrhythmia P-P
regularly irregular short with inspiration, long with expiration
Causes of Sinus Dysrhythmia
common in young children and young adults
Effects of Sinus Dysrhythmia
alters filling time, variable oxygen demand
Treatment of Sinus Dysrhythmia
none
Sinus Arrest Rate
Rate normal to slow
Sinus Arrest Rhythm
Irregular
Sinus Arrest P waves
normal morphology
Sinus Arrest PRI
.12-.20 seconds (normal)
Sinus Arrest QRS
.04-.10 seconds (normal)
Causes of Sinus Arrest
Ischemia of SA node, Digitalis toxicity, Excessive vagal tone
Effect of Sinus Arrest
Frequent or prolonged episodes of dec C.O.; cardiac standstill, cessation of SA node activity
Treatment of Sinus Arrest
observe if asymptomatic; bradycardic with symptoms treat w/ atropine 0.5mg bolus; pacer
Atrial Tachycardia HR
150-250
Atrial
(blank)
Who is most often affected by atrial tachycardia
kids
Atrial Tachycardia is also known as
SupraVentricular Tachycardia (SVT)
Effects of Atrial Tachycardia
decreased filling times, decreased MAP, increased myocardial O2 demand and work
Treatment of Atrial Tachycardia
control ventricular rate, digoxin, calcium blockers, vagal stimulation, override pacer, cardioversion
Saw Tooth Patter =
Atrial flutter
Atrial Flutter atrial rates
200-400 bpm
Atrial Flutter ventricular rates
140-160 bpm
Atrial Flutter typical rhythm
regular
Most common atrial flutter rate is
300 bpm
Most common atrial flutter conduction rate is
2:1
Most common atrial flutter ventricular response
150 bpm
Atrial flutter with variable conduction is caused by
constant fluctuations in the conduction ratios through the AV node - (AV node holds on)
Atrial Flutter causes
increased atrial automaticity, atrial re-entry; digoxin (common), hypokalemia, aging
Effects of Atrial Flutter
decreased filling time, loss of atrial kick, decreased MAP,
Treatment of Atrial Flutter
control ventricular rate, digoxin, calcium channel blockers, vagal stimulation, over-ride pacer, cardioversion
Atrial Fibrillation is mostly common in
adults
Atrial Fibrillation PRI
No PRI
Atrial Fibrillation Pulse rate
>300 and usually not observable
Atrial Fibrillation P wave
P wave "f" waves or fibrillatory waves
Atrial Fibrillation QRS rate
variable
Atrial Fibrillation rhythm
irregularly irregular
Atrial Fibrillation P waves
absence of observable P waves
Filbillatory or "f" waves occur at the rate of
400-700 bpm
Causes of Atrial Fibrillation
increased atrial automaticity, atrial re-entry, digoxin (common), hypokalemia, aging
Differential Diagnosis of Atrial Fibrillation
Atrial enlargement (esp left), age >60, MAD RAT PPP, Idiopathic
Effects of Atrial Fibrillation
decreased filling time, loss of atrial kick, decreased MAP
Treatment of Atrial Fibrillation
control ventricular rate, Digoxin, calcium blockers, vagal stimulation, over-ride pacer, cardioversion
What does MAD RAT PPP stand for
Myocardial infarction; Atherosclerosis; Drugs: digoxin; Rheumatic heart disease; Alcoholic holiday heart; Thyrotoxicosis (endocrine); Pulmonary emboli; Pericarditis; Pneumonia: right middle lobe
Junctional Rhythm is associated with which node
AV
Junction Rhythm P wave
absent, inverted, biphasic or after the QRS
Junction Rhythm QRS
.04-.10 seconds (normal)
Junctional Rhythm Rate
40-60 bpm and regular
Causes of Junctional Rhythm
atrial and sinus bradycardia, standstill or block
Effect of Junctional Rhythm
Decreased C.O., loss of atrial kick, decreased MAP,
Treatment of Junctional Rhythm
treat cause if hypotensive, pacer, atropine
Junctional Bradycardia P wave
absent, inverted, biphasic or after the QRS
Junctional Bradycardia QRS
.04-.10 seconds (normal)
Junctional Bradycardia Rate
<40
Causes of Junctional Bradycardia
Atrial & sinus bradycardia, standstill, or block (SA node isn't working), vagal hyperactivity
Effects of Junctional Bradycardia
Decreased C.O, loss of atrial kick, decreased MAP
Treatment of Junctional Bradycardia
treat cause if hypotensive; pacer, atropine
Premature Junctional Contractions (PJC)
Early beat without P waves
Premature Junctional Contractions (PJC) QRS morphology
.04-.10 (normal)
Causes of Premature Junctional Contractions
Hyperkalemia (6-5/4mEq/L), hypercalcemia, hypoxia, elevated preload
Effects of Prejature Junctional Contractions
Decreased C.O., loss of atrial contribution to ventricular preload for that beat
Treatment of Premature Junctional Contractions
treat the underlying cause
Accelerated Junctional Rhythm P wave
absent, inverted, biphasic or after QRS
Accelerated Junctional Rhythm QRS morphology
.04-.10 seconds (normal)
Accelerated Junctional Rhythm HR
60-100 bpm, regular
Causes of Accelerated Junctional Rhythm
Hyperkalemia, Hypercalcemia, Hypoxia, Elevated preload
Effects of Accelerated Junctional Rhythm
Decreased C.O., Loss of atrial contribution to ventricular preload
Treatment of Accelerated Junctional Rhythm
treat the underlying cause
Junctional Tachycardia HR
100-130 bpm, regular
Junctional Tachycardia P wave morphology
absent, inverted, biphasic or after the QRS
Junctional Tachycardia QRS
.04-.10 seconds (normal
Causes of Junctional Tachycardia
Hyperkalemia, Hypercalcemia, Hypoxia, Elevated preload
Effects of Junctional Tachycardia
Decreased C.O., loss of atrial contribution to ventricular preload, increased myocardial oxygen demand and workload
Treatment of Junctional Tachycardia
treat the underlying cause
Definition of Accelerated Junctional Rhythm
Junctional rhythm with rates of between 60-100 bpm
Definition of Junctional Tachycardia
Junctional Rhythm with rates between 100-130 bpm
Junctional Rhythm that exceeds 140 bpm
AV nodal reentry tachycardia (AVNRT); Rates between 130-140 can be called either junctional tach or AVNRT
QRS complex widens
the lower you go
Premature Ventricular Contraction (PVC)
Early beat with P wave - QRS usual opposite in deflection
Causes of PVC's
aginag and induction of anesthesia, myocardial ischemia, hypoxia, acid-base disturbances, eletrolyte disturbances, increased sympathetic tone
Effect of PVC's
Decreased C.O., loss of atrial contribution to ventricular preload for that beat
Treatment of PVC's
If frequent and symptomatic give amiodorone
Unifocal PVC
mach each other
Differential Diagnosis of PVC's
idiopathic and benign, anxiety, fatigue, drugs: nicotine, alcohol, caffeine; heart disease, electrolyte disorder
Ventricular Tachycardia Rate
100-250, regular
Ventricular Tachycardia P waves
if P waves are present, they are not associated with QRS complexes
Ventricular Tachycardia PRI
none
Ventricular Tachycardia QRS
greater than .12 seconds
Causes of Ventricular Tachycardia
aging & induction of anesthesia; myocardial ischemia; hypoxia; acid-base disturbances; electrolyte disturbances; increased sympathetic tone
If patient is in Ventricular Tachycardia and has no pulse
defibrilate at 200 joules
If patient is in Ventricular Tachycardia and has a pulse -
treat with amiodorone
Is Ventricular Tachycardia life threatening?
Yes
Effects of Ventricular Tachycardia
Decreased C.O., loss of atrial contribution to ventricular preload for that beat
Ventricular Fibrillation rhythm
chaotic
Ventricular Fibrillation P wave
None
Ventricular Fibrillation QRS
None
Causes of Ventricular Fibrillation
Aging & induction of anesthesia, myocardial ischemia, hypoxia, acid-base disturbances, electrolyte disturbances, increased sympathetic tone, rapid infusion of potassium
What is the number one cause of sudden cardiac death
ventricular fibrillation
Effect of Ventricular Fibrillation
Lethal, no C.O.
Treatment of Ventricular Fibrillation
defibrillation and consider possible causes, Amiodorone
If in V-Fib
De-Fib
Treatment of Torsades De Pointes
try to defib (usually cannot be converted) then **administer Magneusium Sulfate
Torsade de Pointes HR
200-250 bpn, irregular
Torsade de Pointes P wave
None
Torsade de Pointes QRS
None
Torsade de Pointes PRI
none
First Degree Block Rate
depends on underlying rhythm
First Degree Block Rhythm
regular
First Degree Block P waves
normal PRI >.20 seconds
First Degree Block QRS
normally less than .12 seconds
Causes of First Degree Block
Hyperkalemia, Hypokalemia, Endocarditis, Age, Ischemia at the AV junction
Effects of First Degree Block
None
Treatment of First Degree Block
None
Asystole QRS
absent
Asystole P wave
absent
Treatment of Asystole
CPR, pacer, 1mg epinephrine, 1mg Atropine
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