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Which wave represents activity in SA node?
- P wave.
- Atrial depolarization.
What does QRS represent?
What represents repolarization of the ventricles?
What is J point?
Where QRS returns to baseline.
What is the PR interval?
- Want it to be around .1-.2 seconds.
How long should the QRS last?
- <.12 seconds.
- Anything greater think pathology.
What is absolute refractory?
- Period of depolarization during which no other stimuli can initiate an action potential.
- Like flushing a toilet. Cannot reflush.
- Period of repolarization during which new stimuli CAN initiate action potential.
- As bowl is refilling, can reflush toilet but flush will not be effective.
What does the QT interval represent?
- Entire electrolyte exchange (depolar/repolarization) of the ventricles.
- Acceptible range varies depending on age, HR, and gender.
- >.50 is too long regardless.
- If QT interval lengthens (after QRS), it leaves the ventricles vulnerable to extra contractions during the relative refractory period.
- --Usually due to drugs, pretty much all of them.
What does an R to R interval tell you?
Tells you the regularity of the beat.
What does intercranial bleeding have to do with bradycardia?
- Bradycardia is the natural response to intercranial bleeding. There is nothing wrong with the heart.
- The same occluded airways with peds.
- In either case, DO NOT TREAT THE BRADYCARDIA because ^HR-->^bleeding/respiration.
How do you treat a legit bradycardic condition?
- Atropine-->blocks parasympathetic action allowing sympathetic response to dominate.
- Assessment will look for return of color, warmth, loc, etc...
- Treat only if adverse symptoms (other than bradycardia) exist.
- Monitor vomiting. Vegal nerve stimulation may trigger bradycardia.
What do you need to know about treatment of sinus tachycardia?
- TREAT THE CAUSE!!, not the tachycardia.
- 1) Hypoxemia
- 2) Fever
- 3) Hypovolemic/hemorrhage
Whatever it is, it's never nothing.
Digoxin and beta-blockers will slow HR, but do not treat the rate, TREAT THE CAUSE.
Quick and dirty method of evaluating HR
- OK? Sinus rhythm.
- Too slow? Not enough BPM to be effective.
- Too fast? Not enough fill time to produce adequate CO.
- Too unorganized?
What is sinus arrythmia?
- Normal everything except irregular RR interval.
- Usually caused by difference between HR during inspiration and expiration.
- More typical in children and thin people.
- Junctional = AV node.
- No P wave, or irrelevent P.
- No atrial kick
- 40-60BPM. If rate is 61-100 then accelerated junctional rhythm.
- Can be triggered by drugs, tissue damage (escemia, infarction, etc). Issue is most likely with atrium.
- Treat with atropine, but will not be as effective because you need healthy atria for atropine to work well.
What is supraventricular tachycardia? (SVT)
- Some node above the ventricles (SA or AV) is going nuts.
- Rate > 150.
- Pounding in chest
- Tickling in throat (aortic arch)
- Know something is very wrong.
- Diagnose (not you, an IP) with carotid/sinus massage. HR will slow down enough to find a P wave.
- Use beta-blockers to slow it down.
- Can use defib (low voltage) to reset. Called cardioeversion.
- Can have pt bear down, squat, face in cold water.
- Verapamil-->vomiting to stimulate vegal nerve-->bradycardia.
Same thing as SVT, but transient.
- Elongated QRS (>0.12 sec)
- Electrical impulse takes a longer detour through ventricle.
- 20-40/min--> v CO.
- Assessment will include fatigue, faint, v respirations.
- May need to be "paced."
- Usually survivable, but pt may pass out due to low CO.
Accelorated idioventricular rhythm.
- No P wave
- IVR with 60-100/min
- Wide QRS.
- Will have runs of accelerated IVR after clotbusters because toxins from infarcted tissue will suddenly bet dumped into the BS, aka reperfusion arrhythmia. If so, then it should go away. If not...
- ...OH SHIT.