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Flashcards in EKG/ Arrhythmias Deck (37):
0

What does P wave represent

Atrial depolarization

1

QRS complex

ventricular depolarization

2

PR interval; how many boxes is normal length

conduction delay through AV node

*less than 5 little boxes (under 200 msec; one little box is 0.04 s)

3

QT interval

mechanical contraction of ventricles

4

T wave

ventricular repolarization

*T wave inversion may indicate recent MI

5

Chaotic and irregularly irregular baseline with NO p-waves

Atrial fibrillation

6

Sawtooth pattern due to identical, back to back atrial depolarization waves

Atrial flutter

7

PR interval over 200 ms long; what two drug classes can cause?

1st degree heart block

*can be caused by Beta blockers and CCBs

8

Progressive lengthening of PR interval until a beat is dropped (p wave not followed by a QRS complex)

Mobitz type 1 2nd degree block (Wenkebach)

9

Dropped beat not preceded by a change in length of PR interval

Mobitz type II 2nd degree block

11

atria and ventricles beat independently of each other (p wave and QRS complexes have no resemblance to each other)

3rd degree (complete) heart block

*atrial rate is faster than ventricular

12

Delta waves (representing early ventricular depolarization)

Wolff-Parkinson-White syndrome (accessory signal that bypasses the AV node; also called ventricular pre-excitation syndrome)--> delta wave is caused by early ventricular depolarization, is where PR interval should be

13

Wide QRS after long pause; usually there is associated bradycardia; no p-wave

Ventricular Escape rhythm (failure of SA or AV node to originate a signal, eventually kind of just beat on their own due to intrinsic pacemaker activity)

13

Undulating amplitude of QRS may decompensate into v-fib

Torsades de pointe

14

wide QRS with tachycardia

Ventricular Tachycardia

15

Anything that prolongs the QT interval may predispose to what?

Torsades de pointe

16

What are 3 antibacterials that may prolong the QT interval?

Macrolides (esp erythromycin)
Chloroquine
Mefloquine

17

What two antipsychotics may prolong QT interval?

haloperidol and risperidone (other as well)

18

Which HIV drug class may prolong QT interval?

Protease inhibitors (-navir)

19

What two anti-arrythmic classes may cause QT prolongation?

1A --> quinidine
III --> sotolol, amiodarone

20

All together, what drugs prolong QT interval?

Macrolides (erythromycin), chloroquine and mefloquine
Haloperidol, risperidone
Protease inhibitors
Quinidine, amiodarone, sotalol

21

How does Ventricular fibrillation look on EKG?

Completely erratic rhythm with NO IDENTIFIABLE WAVES

*fatal without immediate CPR and defibrillation

23

Tx for acute Atrial fibrillation?

cardioversion

24

Tx for chronic A-fib?

Anticoagulation
Rate control (digoxin, BB, CCBs)
Rhythm control (sotalol, amiodarone)

*DONT CARDIOVERT TO NORMAL RHYTHM IF PRESENT OVER 48 HRS!! if clot has formed, normal rhythm may shake loose a clot that has formed--> stroke or PE will ensue

25

what does a narrow QRS indicate in general

that the signal is originating above the ventricles (SA or AV node)

26

AV node is pacemaker (narrow QRS), but slow rate

Junctional Escape Rhythm

27

early wide QRS with bizarre morphology, no p-waves

Premature Ventricular contractions (QRS is over 4 little boxes when normal is 1)

28

what causes PVCs?

microentry at the level of Purkinje fibers--> wide QRS tell you the signal is originating somewhere below the AV node

29

what can WPW lead to if not treated

Supraventricular tachycardia

30

ventricular bigeminy

PVC follows each sinus beat

31

ventricular trigeminy

2 sinus beats followed by a PVC

32

What does the height of the p-wave correlate with?

the K+ level--> too tall means hyperkalemia; flat p-wave can mean hypokalemia

33

what does the delay in the AV node allow for

ventricular filling

34

ST segment

represents the period in which the ventricles are depolarized; is isoelectric normally--> how long ventricles are deploarized

35

where is speed of conduction fastes?

purkinje fibers > atria > ventricles > AV node

36

tx for torsades

Mg sulfate

37

congenital long QT syndromes + severe congenital deafness

Jervell and Lange-Nielson syndrome--> due to defective cardiac Na or K channels

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