Week 8: Cardiac Emergencies and Life Saving Interventions: Part 1 Flashcards
Pacemaker Cells
ability to initiate an electrical impulse within themselves (automaticity)
- SA node, AV node, Junction, Purkinje fibers
- SA: originates electrical impulse. Allows working cells to react
excitability
ability of all cells to react to electrical impulse
Isometric Line
- Resting membrane potential of cardiac cells
- There is a lack of movement of ions
As potassium is moved outside of the cells the intracellular potential becomes?
increasingly negative
cardiac conduction pathway
SA node–>AV node–> Bundle of Hiss—> left and right bundle branches–> purkinje fibers.
SA node
Sinus node. Dominant pacemaker of the heart. Upper posterior wall location of the right atrium. Results in the depolarization of the heart.
AV node
-located in posterior wall of R atrium below tricuspid valve. Allows atrial conduction to move into ventricular portion of the heart allowing ventricular contraction
lead normally used in ecg monitoring
lead 2. Looking through the heart at the patient’s right side of the heart and up into the heart watching the electrical impulse that’s being generated.
p wave
arterial depolarization
pq and pr segments
conduction through AV node and AV bundle
ST segment
ventricles contract
t wave
ventricular repolarization
rule of 300
Divide 300 by the number of boxes between each QRS = rate
6 second method
distance between the number of boxes until you get to the initiation of the second beat. Multiply how many complete complexes you have within 6 seconds, times 10 gets you a heart rate/minute.
normal PR, QRS, and QT
PR
0.20 sec (less than one large box)
QRS
0.08 – 0.10 sec (1-2 small boxes)
QT
Half the R-R interval with normal HR
0.38-0.42 seconds
type of rhythm?
Originating from SA node
P wave before every QRS
P wave in same direction as QRS
PR 0.12- 0.20
QRS less than 0.12
Sinus:
type of rhythm?
- Regular rhythm, rate less than 60
- P waves present before each QRS and between 0.12-.020
- QRS less than 0.12
sinus bradycardia
Treatments of Sinus Bradycardia
Atropine
-0.5mg IV bolus
-Repeat every 5 min
-Max dose 3 mg
-Side effects: Dry mouth, Blurred vision, Urinary retention,
Less than 0.5 mg, Slowed heart rate
type of rhythm?
- Rhythm regular, rate greater 100
- P Waves present before each QRS, PR interval .12- .20
- QRS less than 0.12
sinus tachycardia
treatment of sinus tachycardia?
ID cause and tx
Pain
Anxiety
Infection
CHF
MI
Characterized by:
- Varied rate with periods of bradycardia and tachycardia
- Caused by dysfunction of SA node without escape mechanisms
- Seen in elderly
- QRS narrow
- R to R irregular
sick sinus syndrome
treatment of sick sinus syndrome
symptomatic tx:
ex: If too brady, give atropine and 02
- Rapid rate usually above 150 to 250 bpm
- P waves hidden behind t waves
- QRS complex narrow
- R to R regular
supraventricular tachycardia
treatment of SVT
Oxygen
Adenosine
- 6mg IV push fast
- Repeat with 12mg if needed
- Causes asystole
- run a continuous strip
- Rapid depolarization of the AV node
- Usually a regular rhythm
- Narrow QRS
- Atrial rate can be up to 350 bpm
atrial flutter
treatment of atrial flutter
Adenosine
Calcium Channel Blockers (Diltiazem)
-Slow conduction
-15-20 mg IVP slow
Beta Blockers
-Decrease HR
-Decrease BP
-Slow IVP
- no effective atrial contraction
- Narrow QRS
- Rhythm irregular
- Rapid ventricular rate 100-160 bpm
atrial fibrillation
treatment of A-fib
- Previous interventions
- Warfarin INR 2-3
- AV node or Bundle of His
- Replace the SA node P wave may be inverted or buried
- Rate 40-60 Junctional escape
- Rate 60+ junctional tachycardia
- QRS regular and narrow
junctional rhythm
treatment of junctional rhythm
tx only if underlying problem
- Just an early beat that originates from the AV node
- Rhythm regular except early beat
- One P wave for each QRS
- QRS narrow
premature atrial contraction
treatment of PAC
tx only if underlying problem
- Early beat with wide QRS complex
- No p wave with beat
premature ventricular contraction
treatment of PVC
- Check electrolytes
- Treat if symptomatic
- QRS greater than 0.12 usually regular
- Sustained vs. Nonsustained
- Usually no p wave
ventricular tachycardia
treatment of ventricular tachycardia
Lidociane
1-1.5mg/kg IV then a maintenance drip 1-3 mg/kg/min
Magnesium
For long QT induced V-tak
1-2mg in 10ml of D5W over 10-20 min
- Undeterminable
- Looks like squiggly lines
ventricular fibrillation
treament of vfib
- CPR
- ACLS
what meds can cause junctional rhythm
digoxin, beta blockers
- Polymorphic V-tak
- Usually underlying long QT interval
torsades de pointes
treatment of torsades
- Magnesium
- Treat underlying cause
- A conduction delay
- Regular rhythm
- PR interval long greater than 0.20
- QRS normal
first degree block
treatment of first degree heart block
treat underlying cause
wide bizar formation of the qrs is indicative of what kind of premature contraction?
premature ventricular contraction
- Regularly irregular
- Progressivly longer PRI until dropped QRS
- QRS narrow
second degree heart block/ Mobitz 1/ Wenckebach
treatments of second degree heart block
- Tx if symptomatic
- Pacing
- Atropine
- PR interval fixed,
- QRS dropped intermittently
- Rapidly progresses
second degree block/Mobitz 2
Treatment of second degree HB/mobitz 2
- pacing
- atropine
Atrial and ventricle disassociated
third degree complete block
treatment for third degree complete block
PACE
- Short PR interval <0.12 sec
- Prolonged QRS >0.10 sec
- Delta wave
- Can simulate ventricular hypertrophy, BBB and previous MI
WPW block
- prolonged QT greater than 0.42
- increased chance of going into a ventricular arrhythmia, most often torsades
- most often congenital in pts with families who had sudden cardiac death under age 50
- treatment=prevention (have you had any syncope, seizures, felt dizzy when you ran)
prolonged QT syndrom
Synchronized shock
- Delivered on R wave
- Pediatric cardioversion gets 0.5-1 J/kg first shock
- Additional cardioversion shocks are at 2 J/kg. - Adult cardioversion
- Cardioversion for atrial rhythms is 50-100-200-300-360 J - Need pain and sedation medication
cardioversion
Unsynchronized
- Pediatric: use a dose of 2 J/kg for the first attempt and 4 J/kg for subsequent attempts.
- Adults: Physio‐Control Biphasic
- 200 joules – 1stshock
- 300 joules – 2nd shock
- 360 joules – all following shocks - Monophasic: 360 joules – all shocks
defibrillation
- implanted
- delivers shock as needed
implantable cardioverter/defibrillator
