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Ability to build up and discharge on electricial stimulus w/o outside stimulation
Found in SA node, AV junction and purkinje fibers
Ability of cell to respond to an outside stimulus. Related to ionic imbalance across the membrane of cells.
Found in all cells
Ability of cardiac muscle to conduct the impulse to an adjacent cardiac cell and is an electric property
Found in all cardiac cells
Mechanical ability of a muscle cell to shorten (contract) in response to electrical stimulus
Extensibility (stretch) vs elasticity (recoil)
What is the normal pacemaker of the heart?
Sinoatrial (SA) node
What is the SA node's property?
What is the regular heart rate that the SA node produces?
What does it look like on the ekg?
No waveform on EKG
What are the 3 P situations that could cause a decrease or increase in heart rate produced by the SA node?
Physiological (i.e. Temp) which increases demand
Pathological (i.e. V-tach) causing the runs
Pharmacological (i.e. OD on drugs)
What is the purpose of the atrioventricular (AV) node?
To delay impulse slightly, allowing atrial kick to occur and contribute ~30% towards EDV.
This protects the ventricles from excessively rapid atrial rates.
What is the name of the electrical connection b/w atria and ventricles?
What is it's inherent heart rate?
Bundle of His
Where does one look on the EKG to determine AV conduction dysrhythmia (heart block)?
What is the name of the terminal portion of conduction system, which carries impulses out into ventricular muscle tissue?
What are the four ions that create electrical activity on an EKG?
What is the normal duration of the P wave?
2 3/4 squares, or 11 secs
What is the normal duration of the PRI?
3-5 small squares, or .0.12-.0.20 secs
P wave reps __________ depolarization while qRs reps _______ depolarization
What is the normal duration of the qRs complex?
0.06-0.12 secs (1.5-3 squares)
What does the ST segment represent on EKG?
ST variations usually represents one of which two events?
- ST depression = ischemia
- ST eleavation = injury
What does the T wave represent on the EKG?
What is it's voltage criteria on Lead II and Lead MCL1?
- Lead II: 5mm
- Lead MCL1: 10mm
What does the QTI represent on EKG?
What are the 3 factors that can cause variations on the QTI?
Total ventricular depolarization and repolarization
Age, gender, HR
If a U wave is present on EKG, what does it represent?
Late repolarization of purkinje fibers
What is the 6 second method?
What is the best scenario to use this method?
Count # of qRs complexes within a period of SIX seconds (30 large boxes) and multiply by 10 = X BPM
Use for highly irregular rhythm
What is the large square R-R method?
What is the best scenario to use this method?
Count # of large squares b/w two consecutive R's and divide into 300
(1 box = 300.... 2 = 150.. 3 = 100... 4 = 75... 5 = 60... 6+ = <60 bradycardia)
Use for regular rhythms
What is the small square R-R method?
What is best scenario to use this method?
Count # of small squares b/w two consecutive R's and divide into 1500... is most accurate than other methods
Use when rhythm is regular
What are the 3 components to dysrhythmia interpretation?
- 1. Impulse origin site (i.e. ventricular rhythm)
- 2. Rate of impulse (i.e. VT)
- 3. Window dressing (i.e. ACS)
List the 7 window dressings that may occur on an EKG and its interpretation.
- 1. Shape of P wave (atrial enlargement?)
- 2. Length and patterns of PRI (heart block? max limit of 5?)
- 3. Width and shape of qRs (conduction delays?)
- 4. ST segment elevation/depression (ACS? Ischemia? Injury?)
- 5. T wave shape and direction (electrolyte abnormalities?)
- 6. QTc duration (pharm. intervention? Upper limit of 11?)
- 7. Extra beats - wide (ventricular), narrow, early or late
What is required on an EKG to be considered a sinus rhythm? (3)
What is ST, SR, and SB?**
- 1. P waves present
- 2. P waves all look similar
- 3. 1:1 ratio of P:qRs
- ST >100bpm
- SR: 60-100bpm
- SB: <60bpm
What are the 3 possible EKG situations to be diagnosed for having a junctional rhythm?
What is the junctional rhythm (JR) HR?
- 1. Inverted P wave in front of qRs and short PRI
- 2. Inverted P wave behind the qRs (ST segment)
- 3. No P wave at all
What are the 4 requirements for diagnosis of ventricular rhythm?
- 1. Usually no P wave
- 2. qRs always WIDE >0.12 secs (3 boxes)
- 3. Increased amplitude, bizarre-shaped
- 4. ST and T wave abnormalities
What are 5 scenarios of ventricular rhythm and its HR (if applicable)?
- 1. VF - total chaotic activity
- 2. TdP - 150-250bpm
- 3. VT - 100-200bpm
- 4. IVR - 20-40bpm
- 5. Early ventricular beats (PVC's)
What are the 4 requirements for diagnosis of AV conduction dysrhythmias?
- 1. P waves present
- 2. P waves all look similar
- 3. More P waves than qRs complexes (2 & 3 degree block)
- 4.Establish P to P interval in order to establish relationship of P's to each other (proves its coming from SA node)
How would one differentiate the 4 AV conduction dysrhythmias: 2nd Deg TI, 2nd Deg TII, 2nd Deg 2:1, 3rd Deg?
Look at PR segment --> Looks same --> 2nd Deg TII and 2nd Deg 2:1 --> Has 2 P waves for each QRS --> 2nd Deg 2:1
Look at PR segment --> Looks diff --> 2nd Deg TI and 3rd Deg --> Ventricular rhythm irregular -->2nd Deg TI
What are the 4 (1 each) requirements for diagnosis of atrial rhythm?
- 1. No isoelectric line b/w qRs complexes (AT)
- 2. AT with P/T waves becoming one and rate of 160-240bpm
- 3. Aflutter - sawtooth formation at rate of 250-350bpm
- 4. Afib - low voltage undulations at rate >350bpm
In general, of the 5, which 2 are possible rhythms if no P waves are present on EKG?
SR, AR, AV blocks, JR, VR
What is alpha1, beta1, and beta2's actions?
- Inc'd HR, conduction, contractility
What are the 4 best diagnoses in which one would use epinephrine?
- Pulseless VT
What is the dosing of Epinephrine for IV, IO, and ET?
IV and IO: 1mg q3-5mins, no MAX (for IV, follow with 20ml NS flush)
ET: 2-2.5mg, add 10mls NS, no MAX
What are the four indications for using Vasopressin (same as Epi)?
- Pulseless VT
How does one dose Vasopressin during a cardiac arrest situation?
- Single use only
- 40 Units IV or IO as alternative to 1st or 2nd Epi dose
- May return to Epi 10 mins after Vasopressin dose if still pulesless
What is the dosing of Amiodarone during cardiac arrest?
300mg IVP in 20-30ml soln total --> Repeat in 3-5mins with 150mg IVP in 20-30ml soln total
- Post-code infusion: 900mg/500mls D5W
- -->1mg/min x6h
- -->Then 0.5mg/min x18h
What is the dosing of Amiodarone during stable tachy?
Rapid inf: 150mg diluted in 50-100ml soln over 10mins
--> Followup in 10-15mins with 900mg/500mls with initial rate of 1mg/min x6h --> Maintain with 0.5mg/min x18h
What is the biggest precaution w/using Amiodarone?
May prolong QTI, so dont give routinely with other QT-prolonging drugs
What is the dosing of Lidocaine for cardiac arrest? What is the max dose?
1.5mg/kg IVP, repeat q3-5mins with same or 1/2 dose.
ET: 2-2.5x the above dose, diluted in 10ml NS
Post-code: 1g/250ml with range of 2-4mg/min
What is the dosing of Lidocaine in stable tachy? What is max dose?
1mg/kg IVP then repeat in 5-10mins with 0.5mg/kg IVP
Then follow up with 1g/250mls with range of 2-4mg/min
What is the biggest precaution with using Lidocaine?
CNS toxicity like slurred speech, muscle twitching, seizures, altered loss of consciousness
What are the 3 indications for using Procainamide?
- Ventricular ectopy
- VT w/a pulse
- Stable wide QRS complex tachy with uncertain origin
What is the dosing for Procainamide?
LD of 17mg/kg @20-30mg/min
Then followup with 1g/250mls at 2mg/min
What are the 3 indications for emergency use of Mg?
- Torsade de Pointe (TdP) - 1st line
- Pulseless VT
- Pulseless VF
- ^3rd line to latter two when refractory to Amiodarone and Lidocaine
What is the dosing of Mg? What is max dose?
1-2 GRAMS IV/IO diluted in 10ml soln over 1-2mins
What is the DOC for bradycardia?
What are the 2 requirements for using Atropine?
- 1. HR<60bpm
- 2. Pt is symptomatic - hypotension, chest pn, nausea, diaphoresis (excessive sweating)
What is the dosing for Atropine? What is max dose?
0.5mg IVP, repeat dose q3-5 mins with max of 3mg
Atropine works BEST in which type of symptomatic bradycardia?
Narrow QRS complex bradycardia
What are the two classes of drugs, and 4 miscellaneous drugs that will work on narrow QRS complex tachycardia? Which drug is 1st line?
- 1. CCB
- 2. BB
- 3. Adenosine
- 4. Digoxin
- 5. Procainamide
- 6. Amiodarone
What is the dosing of Adenosine? What is max dose?
6mg IVP over 1-3 secs --> Repeat with 12mg q1-2mins -->Repeat with 12mg q1-2mins -->Max dose: 30mg
**Flush each bolus with 20ml NS
Which pressor drugs may be used for SBP<70, SBP of 70-100, and SBP >100, respectively?
What are the three activities dealing with monomorphic VT management? (very general)
- 1. Loading dose
- Amiodarone (150mg)
- Lidocaine (1mg/kg)
- 2. Follow w/Cont. Inf
- Amiodarone (1mg/min)
- Lidocaine (2mg/min)
3. Electrical intervention - Sedate, then synchronize with 100 Joules
Just like treating VT with pulse, what are the three drugs used, in addition to which other drug that may be included in choice of tx?
Then synchronize at 100J
In which 2 scenarios would one choose Adenosine or CCB/BB during a narrow complex tachycardia situation/
Regular rhythm, rate>160bpm --> Choose Adenosine
Irregular rhythm, rate >100bpm --> Choose CCB/BB
What are the steps to take in dealing with a pt having narrow complex tachycardia (NCT)?
- 1. Regular/irregular rhythm --> Give Adenosine or CCB/BB
- 2. Sedate pt
- 3. Synchronize with 50J
What are the steps to take in dealing with a pt having symptomatic bradycardia?
- 1. Atropine: 0.5mg q3-5mins, max 3mg
- 2. Transcutaneous Pacer (TCP, external pacemaker) at 80bpm
- 3. If pacer not available or above 2 doesnt work (BP still low), try:
- DA drip at 400mg/250ml with range of 5-20microgrm/kg/min (beta range), or:
- Epi 2-10mcg/min
What is the immediate general tx for ACS (ST elevation)?
- 1. Morphine 2-5mg IV if BP<90
- 2. Oxygen at 4L/min
- 3. NTG (SL, patch, nasal) if BP>90
- 4. ASA 325mg, chewable
What are the basic interventions for the following high, med, low risk groups?
ST elevation and BBB
ST depression or T wave inversion
Normal/non-diagnostic changes in ST/T
- 1. ST elevation - cath lab, reperfusion strategy (angioplasty, stents)
- 2. ST depression - adjunctive pharm Rx (Nitro, BB, plavix, heparin)
- 3. Nondiagnostic changes in ST/T - observation (serial ECG's, enzymes, ST segment monitoring) and workup
After intubation, what else should be done for the pt immediately after?
8-10 breaths/min, asynchronized with chest compressions.
Without the tube, 30:2
W/o giving specifics, what is the plan for dealing with cases of pulseless VT/VF?
- 1. CPR
- 2. Shock @360J
- 3. IV/IO drug
- 4. Intubate
What are the 2 DOC in a pulseless VT/VF situation after shocking the pt? What are the dosings?
- 1. 1mg Epi (w/20ml NS flush) q3-5mins
- 2. 40Units IVP Vasopressin ONCE, may repeat Epi after 10mins
In a pulselessVT/VF situation, after giving Epi or Vasopressin, there are 3 other drugs that may be alternated w/shocking the pt. What are they, and what is the dosing?
1. Amiodarone 300mg diluted in 20mls total soln, q3-5mins. Then 900mg/500mls at 1mg/min x6h, then 0.5mg/min x18h
2. Lidocaine, 1.5mg/kg q3-5mins, then 1g/250ml at 2-4mg/min
3. Magnesium, 1-2g IV over 2mins and diluted in 10ml solution
What are the 2 1st-line meds for use in a PEA pt? What are the dosings?
- 1. Epi 1mg IV over 3-5mins
- 2. Vasopressin 40Units IVP once, wait 10 mins until give Epi
What are the 5 H's that causes PEA, and the basic solutions to each?
- 1. Hypovolemia - give NS
- 2. Hypoxia - intubate
- 3. H ion (acidosis) - oxygenate, perfuse, buffers
- 4. Hyper/hypokalemia - cant be fixed in code blue
- 5. Hypothermia
What are the 5 T's that causes PEA?
- 1. Toxins
- 2. Tamponade (cardiac)
- 3. Tension pneumothorax
- 4. Thrombosis, coronary (ACS)
- 5. Thrombosis, pulmonary (PE)
What are the 2 tx options for pts w/asystole and the dosing?
- 1. 1mg Epi IV q3-5mins
- 2. 40U Vasopressin IVP once, wait 10 mins until give Epi
**Post-cardiac arrest: What is your immediate priority after ROSC (return of spontaneous circulation)?
- Optimize ventilation and oxygenation
- Ventilate at 10-12 breaths/min -->Titrate to target PETCO2 of 35-40mmHg
**Post-cardiac arrest: If SBP<90mmHg, how would you treat it?
Give IV/IO bolus of 1-2L NS
**What type of pt would you not induce hypothermia to?
**When dealing with a stroke pt, what would you do when your hospital has no CT machine?
Divert to hospital with a CT scanner
**While defibbing a pt, would it be a good idea to run oxygen across the pt's chest?
No, causes fire
**How would you suction (??)?
Suction on the way out, <10 secs
**Which scale would you use in a suspected stroke pt?
Cincinnati pre-hospital stroke scale: Facial droop, arm drift, abnormal speech
What are the 4 ACLS drugs that may be adminstered ET'ly?