EKG/ Arrhythmias

Question 0

QRS complex

Answer 0

ventricular depolarization

Question 1

What does P wave represent

Answer 1

Atrial depolarization

Question 2

PR interval; how many boxes is normal length

Answer 2

conduction delay through AV node

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

Question 3

QT interval

Answer 3

mechanical contraction of ventricles

Question 4

T wave

Answer 4

ventricular repolarization

*T wave inversion may indicate recent MI

Question 5

Chaotic and irregularly irregular baseline with NO p-waves

Answer 5

Atrial fibrillation

Question 6

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

Answer 6

Atrial flutter

Question 7

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

Answer 7

1st degree heart block

*can be caused by Beta blockers and CCBs

Question 8

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

Answer 8

Mobitz type 1 2nd degree block (Wenkebach)

Question 9

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

Answer 9

Mobitz type II 2nd degree block

Question 11

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

Answer 11

3rd degree (complete) heart block

*atrial rate is faster than ventricular

Question 12

Delta waves (representing early ventricular depolarization)

Answer 12

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

Question 13

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

Answer 13

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)

Question 13

Undulating amplitude of QRS may decompensate into v-fib

Answer 13

Torsades de pointe

Question 14

wide QRS with tachycardia

Answer 14

Ventricular Tachycardia

Question 15

Anything that prolongs the QT interval may predispose to what?

Answer 15

Torsades de pointe

Question 16

What are 3 antibacterials that may prolong the QT interval?

Answer 16

Macrolides (esp erythromycin)
Chloroquine
Mefloquine

Question 17

What two antipsychotics may prolong QT interval?

Answer 17

haloperidol and risperidone (other as well)

Question 18

Which HIV drug class may prolong QT interval?

Answer 18

Protease inhibitors (-navir)

Question 19

What two anti-arrythmic classes may cause QT prolongation?

Answer 19

1A –> quinidine

III –> sotolol, amiodarone

Question 20

All together, what drugs prolong QT interval?

Answer 20

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

Question 21

How does Ventricular fibrillation look on EKG?

Answer 21

Completely erratic rhythm with NO IDENTIFIABLE WAVES

*fatal without immediate CPR and defibrillation

Question 23

Tx for acute Atrial fibrillation?

Answer 23

cardioversion

Question 24

Tx for chronic A-fib?

Answer 24

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

Question 25

what does a narrow QRS indicate in general

Answer 25

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

Question 26

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

Answer 26

Junctional Escape Rhythm

Question 27

early wide QRS with bizarre morphology, no p-waves

Answer 27

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

Question 28

what causes PVCs?

Answer 28

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

Question 29

what can WPW lead to if not treated

Answer 29

Supraventricular tachycardia

Question 30

ventricular bigeminy

Answer 30

PVC follows each sinus beat

Question 31

ventricular trigeminy

Answer 31

2 sinus beats followed by a PVC

Question 32

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

Answer 32

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

Question 33

what does the delay in the AV node allow for

Answer 33

ventricular filling

Question 34

ST segment

Answer 34

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

Question 35

where is speed of conduction fastes?

Answer 35

purkinje fibers > atria > ventricles > AV node

Question 36

tx for torsades

Answer 36

Mg sulfate

Question 37

congenital long QT syndromes + severe congenital deafness

Answer 37

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