EKG

Question 1

What 3 main ion currents dominate and at which parts of the cardiac cycle?

Answer 1

Phase 0 – Sodium Channel
Phase 1 – Sodium and Potassium Channel
Phase 2 – Potassium and Calcium Channels
Phase 3 – Potassium Channel
Phase 4 – Potassium Channel and Funny Current

Question 2

What are the 4 classes of antiarrhythmatic meds?

Answer 2

•Class I: Sodium channel blockers
–Inhibit depolarization/slow conduction velocity

•Class II: Beta-blockers
–Slow sinus node and AV node

•Class III: Potassium channel blockers
–Prolong repolarization

•Class IV: Calcium-channel blockers
–Slow SA node (some) and AV node (more)

•Others: Digoxin, Adenosine, Atropine

Question 3

Where do you place EKG leads –where on chest/body?

Answer 3

Question 4

What are the 3 limb unipolar leads?

Answer 4

Use “ground” as composite as the major negative pole

aVR, aVF, aVL

Question 5

What are the 3 bipolar limb leads?

Answer 5

Where you subtract the difference between two leads:

I = R arm (-) –> L arm (+)

II = R arm (-) –> leg (+)

III = L arm (-) –> leg (+)

Question 6

What is the axial reference system?

Answer 6

Shows you the angle from which you are looking at each lead

Question 7

What is the count off system for calculating HR?

Answer 7

Count how many small boxes there are between peaks

Question 8

Which leads indicate problem with inferior potion of heart i.e. pathological Q wave? Which artery is this?

Answer 8

II, III, aVF

RCA

Question 9

Which leads indicate problem with anteroseptal potion of heart? Which artery is this?

Answer 9

V1, V2

LAD, proximal

Question 10

Which leads indicate problem with anteroapical potion of heart? Which artery is this?

Answer 10

V3, V4

LAD, distal

Question 11

Which leads indicate problem with anterolateral potion of heart? Which artery is this?

Answer 11

V5, V6, I, AVL

Circumflex

Question 12

Which leads indicate problem with posterior potion of heart? Which artery is this?

Answer 12

V1, V2 (tall R, not Q wave)

RCA

Question 13

AVNRT: what is it and treatment

Answer 13

Atrioventricular nodal tachycardia

Blip in p wave at end of QRS due to self perpetuating loop in tissue secondary to atrial premature beat

Treat w vagal maneuvers

Question 14

AVRT: what is it and treatmnet

Answer 14

Atrioventricular reentry tachycardia

Bypass tract –> signal can reach ventricles faster = wolff-parkinson white syndrome

short PR, delta wave in QRS, wide QRS

Treat with vagal maneuvers

Question 15

Atrial tachycardia: what is it and treatmnet

Answer 15

Many p waves, with diff morphologies

Beta blockers, Ca channel blockers, IA, IC, and II antiarrhythmic drugs

Question 16

AFib: what is it and treatment

Answer 16

Chaotic depolarization of atria –> irregular Ventricular rate

Anticoags to prevent stroke (CHADS2 score)

No cardiac disease: meds or catheter ablation

Coronary disease: don’t use Class IIC meds (propafenone, flecanide= worse outcome)

Htn, can’t use sotalol, dofetilide (Class III)

CHF: ablation, amiodarone, dofetilide only (Class III)

Question 17

Atrial flutter

Answer 17

Macro re-enterance loop –> sawtooth patterns, more organized rhtyhm than AFib

Question 18

VT

Answer 18

3 or more ventricular premature beats

Wide QRS

Doesn’t respond to vagal maneuvers

Treat with beta blockers, amiodarone & solatol (palliative), ICD, ablation

Question 19

Torsades des Points

Answer 19

Associated with Long QT

Question 20

Long QT- causes and treatment

Answer 20

Congenital, hypokalemia, hypomagnesia, drugs

Withdraw med that causes it, give Mg/K, pace the heart to make it faster, lidocaine, defibrillation

Long term: genetic testing, beta blockers, ICD, avoid meds that prolong QT

Question 21

VFib-treatment

Answer 21

Defibrillation

Question 22

What med do you give to treat sinus bradycardia?

Answer 22

Atropine: blocks action of Ach at parasympathetic sites

Question 23

What are the 4 types of atrial bocks? Treatment?

Answer 23

1st degree: longer PR interval

2nd degree Mobitz type 1/Wenckebach: progressive PR elongation with eventual nonconduction of a p wave

2nd degree Mobitz type 2: normal PR intervals with a sudden failure of p wave to conduct

3rd degree: complete AV dissociation

Treat all with pacemaker

Question 24

Junctional excape rhythm

Answer 24

QRS not preceeded by p wave

Rhythm arises from below atria = slow 40-60 bpm

Question 25

Ventricular escape rhtyhm

Answer 25

widened QRS complexes

Slower rates 30-40 bpm