# Shared Flashcard Set

## Details

EKG
n/a
46
Pre-School
01/21/2010

Term
 PR interval represents what? how long is normal for this interval?
Definition
 AV conduction; normal is < or = to 200 ms
Term
 what is the normal time of a QRS wave? what is considered abnormal?
Definition
 normal 60-100ms; intraventricular conduction delay 100-120ms; bundle branch block >120ms
Term
 what does QT represent? how long is normal?
Definition
 ventricular repolarization; 400ms is normal
Term
 what is a quick way to calculate HR from an EKG?
Definition
 QRS peak separation: 1 block = 300pbm; 2 blocks = 150 bpm; 3 blocks = 100bpm; 4 blocks = 75bpm; 5 blocks=60bpm; 6 blocks = 50 bpm. (60,000/ms between peaks)
Term
 one small box on an EKG represents how many ms? large box?
Definition
 small box = 40ms; large box = 200 ms
Term
Definition
 conditioned athletes and non-stressed people (stronger heart beat = less frequent heart beat)
Term
 when would you see P on T phenomenon?
Definition
 tachycardia moves P and T waves closer together, sometimes the T wave is superimposed on the P wave. in sinus tachy, can still distinguish P, QRS, T
Term
 if we have abnormal beats but theyre the same width as the other normal QRS waves (narrow) what do we assume?
Definition
 they're coming from the same source as the regular beats aka somewhere in the atrium, although not necessarily the SA node
Term
 how do we calculate max HR? and what is needed in stress test?
Definition
 220-age; 85% max hr
Term
 what do we call it when there is irregularity between QRS rhythms?
Definition
 variable ventricular response or variable block
Term
 in which heart problem would you see a saw tooth pattern on the EKG?
Definition
 atrial flutter
Term
 describe atrial fibrillation
Definition
 rapid irregular irregular rhythm with no P waves (chaotic, 400-650 bpm)
Term
 describe atrial flutter
Definition
 atria and ventricle dissociated, lots and lots of P waves at fast rate and QRS waves (not a 1:1 ratio with P waves) every now and then, irregularly placed and slow
Term
 where is the source of trigger for atrial fibrillation?
Definition
 LUNG (pulmonary veins send signals at a fast rate to the heart, irritates the heart)
Term
 98% of ventricular beats that originate in the heart are?
Definition
 re-entrant
Term
 define bigeminy, trigeminy, etc.
Definition
 bigeminy: 1 normal beat and 1 VPD; trigeminy= 2 normal beats and 1 VPD
Term
 what rate is normal for the SA node, AV node and ventricles to beat?
Definition
 SA = 60-100; AV=40-60; ventricles <40
Term
 what usually causes accelerated idioventricular rhythm?
Definition
 usually occurs with reperfusion after an MI. indicates that an artery has been opened successfully. NOT re-entrant; AUTOMATIC!
Term
 monomorphic vs polymorphic
Definition
 monomorphic = redundant and abnormal but same morphology for all peaks; polymorphic = redundant and abnormal but peaks look diff from each other
Term
 how can a person overcome first or second degree heart block?
Definition
 exercise - patient has enough adrenaline/reserve to overcome the block (if exercise makes it worse, they need a pacemaker)
Term
 describe first degree AV block
Definition
 prolonged PR interval, constant relationship between P and QRS >200ms and 1:1 relationship between P, QRS, and T waves
Term
 1st degree heart block is usually caused by what? and originates where?
Definition
 usually in AV node and is related to vagal tone. if we get rid of vagal tone by stimulating them (exercise, adrenaline) then we can get rid of it and overcome it
Term
 describe the 3 kinds of second degree AV block
Definition
 mobitz type 1 = PR interval gets longer and longer with each beat until get a P wave without a QRS; mobitz type II = abrupt drop of QRS; mobitz II to I = can't tell if its 1 or 2 because dropping QRS every other beat so we cannot see if the PR is prolonged
Term
 what is a common EKG abnormality that 75% of people have in their sleep and is of no consequence?
Definition
 wenckeback (mobitz type I second degree AV block) fine bc we wake up and have enough adrenaline to overcome it
Term
 where is the location of the problem in a mobitz type II second degree AV block?
Definition
 at the his/purkinje system (below the AV node) --> therefore the QRS is WIDE. these are unstable and dangerous (need pacemaker)
Term
 describe 3rd degree AV block
Definition
 NO relationship between P and QRS (either more P = 3rd or complete block or less P = A/V dissociation) NO fixed PR interval
Term
 what is the most common cause of complete heart block
Definition
 MI in right coronary artery
Term
 what is the clinical significance of making a distinction between complete heart block (more Ps than QRS) and AV dissociation (less Ps than QRS)?
Definition
 when you have LESS Ps, you can give adrenaline and increase the sinus rate and theres a chance the patient will conduct more and catch up to the ventricular rate. if theres MORE Ps, and we give adrenaline, we get a DECREASE in ventricular response because they already cant accommodate the beats they have
Term
 phase 0 of the AP corresponds to what part of the EKG?
Definition
 phase 0 - upstroke of AP = upstroke of QRS
Term
 when do the absolute and relative refractory periods occur in the AP?
Definition
 absolute refractory period starts at end of phase 1 and extends sometime into phase 3. relative refractory period occurs at the end of phase 3.
Term
 what interval shortens in all of us when we exercise?
Definition
 QT interval (except in people with long QT syndrome, usually female athletes --> sudden death)
Term
 what are the 2 things that determine how quickly impulses are conducted through the heart?
Definition
 1. conduction velocity (slope of phase 0 upstroke) and 2. the refractoriness of the repolarization of the cell
Term
 majority of antiarrhythmic drugs work on which phase of the AP?
Definition
 phase 2-3
Term
 describe the difference between normal and abnormal automaticity
Definition
 normal: SA node is still the pacemaker, introduction of catecholamines can signal the heart to increase HR to meet body's demands; abnormal: myocardial cells OUTSIDE the specialized conduction system acquire automaticity and spontaneously depolarize with the rate of depol exceeding that of the sinus node, so that they take over the pacemaker function and become the source of an abnormal ectopic rhythm
Term
 what normal and abnormal things can lead to automatic rhythms?
Definition
 normal: caffeine, adrenaline, catecholamines; abnormal: MI and reperfusion, electrolyte imbalance,
Term
 what keeps the sinus node beating the fastest (keeps it as the pacemaker)?
Definition
 steeper slope and less negative resting potential
Term
 what causes the action potential (QT) to be prolonged
Definition
 potassium low, magnesium low, or a drug, increased sympathetic tone, decreased parasympathetic tone, hypoxemia, acidosis, bradycardia (prolonging QT increases propensity for EAD)
Term
Definition
 its a specific ventricular arrhythmia caused by early afterdepolarizations (triggered activity)
Term
 what causes sudden death in people with inherited long QT syndrome?
Definition
 early afterdepolarizations are more likely to develop in conditions that prolong the AP duration (QT interval)
Term
 what things lead to late afterdepolarizations?
Definition
 digitalis/digoxin toxicity and other cardiac glycosides(it leads to delayed repolarizations), low potassium, increased calcium, stress
Term
 what do early and late after depolarizations cause?
Definition
 EAD --> torsades de pointes (specific polymorphic ventricular tachycardia); DAD --> frequent ventricular premature depolarizations and palpitations
Term
 3 criteria for reentry
Definition
 1. 2 parallel conducting pathways connected to tissue both proximally and distally 2. difference in the refractoriness of the 2 pathways 3. initiating event
Term
 for reentry, 2 diff conducting pathways have different tissue properties, what are the two types of tissue properties you need?
Definition
 1. slow conduction with shorter refractory period 2. faster conduction with longer refractory period
Term
 what are the 2 types of re-entry
Definition
 macroscopic and microscopic
Term
 what maneuver can we teach pts to help with reentry arrhythmias?
Definition
 vagal maneuvers (bowel movement type) because when you strain a certain way you increase your vagal tone enough to disrupt the circuit if meds dont help
Term
 what is wolff-parkinson-white syndrome?
Definition
 collagen around valve not fully developed --> very THIN defect in the mitral or tricuspid valve --> heart can beat through AV node or through accessory pathway (faster and no filter) --> short PR interval --> can cause a re-entry loop
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