12 Lead EKGs

Question 1

Class I anti arrhythmic drugs

Answer 1

Na channel blockers

• 1a: Qiudinine, procainamide, disopyramide (prolong QT, prolong QTc)
• 1b: Lidocaine, phenytoin, mexiletine (minimal to no EKG changes)
• 1c: Flecainide, propafenone (widened QRS, prolong PRI, sinus node suppression)

Question 2

Class II anti arrhythmic drugs

Answer 2

Beta blockers

• Metoprolol, carvedilol
• Decrease sinus rate, prolong PR, *may contribute to heart block

Question 3

Class III anti arrhythmic drugs

Answer 3

K channel blockers (depolarization)

• Sotalol, dofetilide, dronedarone (prolonged QT)
• Amiodarone (prolonged QTI)

Question 4

Class IV anti arrhythmic drugs

Answer 4

Ca channel blockers

• Verapamil, diltiazem
• Decrease sinus rate, prolonged PR, *may contribute to heart block

Question 5

Other anti arrhythmic drugs

Answer 5

Digoxin, adenosine

Question 6

What does a negative/inverted T wave indicate?

Answer 6

Ischemia or evolving MI

Question 7

What part of the T wave is the heart most susceptible to arrhythmias caused by PVCs?

Answer 7

Second part

Question 8

Normal QTC

Answer 8

Less than .46

Question 9

Left ventricular hypertrophy

Answer 9

• Thickening of myocardium

- Often left axis deviation, wide QRS, LBBB

Question 10

Most common cause of LVH?

Answer 10

HTN

Question 11

Variation of LVH

Answer 11

Hypertrophic cardiomyopathy

- May cause sudden death

Question 12

Pericarditis findings

Answer 12

• Diffuse ST elevation

- PR depression

Question 13

Pericarditis sx

Answer 13

• Pleuritic chest pain, relieved by sitting forward
• May have preceding viral syndrome, fever common
• May have pericardial rub on exam
• SOB if effusion is present

Question 14

Pericarditis tx

Answer 14

• Anti-inflammatories
• Tx of underlying cause
• Drain any effusion present

Question 15

Pericardial effusion

Answer 15

• Can cause global low voltage or electrical alternans

- Can lead to pericardial tamponade

Question 16

Hyperkalemia

Answer 16

• Peaked T waves
• As K increases, conduction system slows (in atria 1st, then ventricles) –> loss of p waves –> new bundle branch block –> bradycardia –> asystole, PEA or VF

Question 17

Hypokalemia findings

Answer 17

• Prolonged QTI
• ST depression
• T wave inversion
• Sometimes large U waves

Question 18

WPW EKG findings

Answer 18

• Short PR interval
• Delta wave
• Widened QRS

Question 19

WPW

Answer 19

Direct connection to ventricle though bundle of Kent

Question 20

WPW tx

Answer 20

If pt has sx, ablation of accessory pathway is necessary

Question 21

What are pulmonary embolisms caused by?

Answer 21

An embolus from the deep venous circulation

Question 22

Risk factors for DVT

Answer 22

Virchow’s triad:

• Venous stasis
• Injury to the vessel wall
• Hypercoagulability

Question 23

Sx of pulmonary embolism

Answer 23

• Dyspnea
• Tachycardia
• Tachypnea
• Pleuritic chest pain
• Sx can be vague

Question 24

Dx of pulmonary embolism

Answer 24

CT scan w/ contrast

Question 25

Tx of pulmonary embolism

Answer 25

Anticoagulation, thrombolytic therapy

Question 26

Axis

Answer 26

- Overall direction of electrical conduction - Found via limb leads - Normal = -30 to 90 degrees

Question 27

Left axis deviation

Answer 27

-30 to -90 degrees

Question 28

Right axis deviation

Answer 28

90 to 180 degrees

Question 29

What does an abnormal axis suggest?

Answer 29

Change in shape/orientation of heart OR defect in conduction system

Question 30

Right atrial enlargement findings on EKG

Answer 30

- Peaked P wave, V1 or inferior leads (greater than 1.5mm in V1, greater than 2.5mm on II)

Question 31

Most common cause of right atrial enlargement?

Answer 31

Pulmonary HTN

Question 32

Left atrial enlargement findings on EKG

Answer 32

- Wide terminal negative portion of the P in V1 (at least 1 small box) - Notched wide P in inferior leads, esp. lead II (at least 3 small boxes)

Question 33

Biatrial enlargement

Answer 33

- Peaked & broad Ps in inferior leads (2.5mm tall & 1.2 seconds wide) - V1 broad & biphasic, w/ terminal negative deflection at least 1mm deep & .04 seconds wide

Question 34

Bundle Branch Blocks

Answer 34

- May be complete or incomplete through one of the bundles - QRS of .1-.12 could mean incomplete or hemiblock - QRS of .12 or greater is likely CBBB (if it does not fit the pattern for RBBB or LBBB, then it is an inter ventricular conduction delay)

Question 35

LBBB

Answer 35

- V1 will be negative, w/ big Q wave or rS complex - V6 will be positive - May also have left axis deviation

Question 36

What is LBBB associated with?

Answer 36

Underlying cardiac disease

Question 37

RBBB

Answer 37

- V1 will be upright & V1-2 will have "bunny ears" appearance - First R wave = LV activation, 2nd R wave is RV activation

Question 38

Lateral leads

Answer 38

I & avL

Question 39

Inferior leads

Answer 39

II, III, & avF

Question 40

Anterior leads

Answer 40

V1, V2, V3, V4

Question 41

Anterio-lateral leads

Answer 41

V5 & V6

Question 42

Sx of STEMIs

Answer 42

- Chest pain (may be vague or absent) - SOB - Diaphoresis - Left arm or jaw discomfort - Back pain btw shoulder blades

Question 43

STEMIs are a result of what?

Answer 43

An occlusive coronary thrombus at site of preexisting atherosclerotic plaque

Question 44

STEMIs tx

Answer 44

- ASA/plavix - Immediate angiography & percutaneous intervention (including stent if needed) - If angiography not available, then thrombolytics are next best option - Morphine, beta blockers, nitrates