12 lead ECG

Question 1

(indicate if positive or negative)
Lead I is bipolar with the _______ electrode at the left arm and the ______ electrode at the right arm. Lead II is _____ in the left leg and ______ in the right arm. Lead III is _____ in left leg and _____ in left arm

Answer 1

positive 
negative 
positive 
negative 
positive 
negative

Question 2

A normal PR interval should be how big?

Answer 2

Less than 1 big box

Question 3

V1-V6 chest leads are _____ and reflect changes in the __________ plane

Answer 3

unipolar

horizontal

Question 4

Increased voltage from right ventricular hypertrophy is seen in which leads?

Answer 4

V1 and V2

Question 5

Septal infarcts are most evident in which leads?

Answer 5

V1 and V2

they are close to the septum

Question 6

Increased voltage from left ventricular hypertrophy and changes from anterolateral infarcts are most evident in which leads?

Answer 6

V5 and V6 bc they are close to the LV, especially its anterolateral portion

Question 7

Normal depolarization of the ventricles goes from ____ to _____ and _____ from the right arm towards the left leg.

Answer 7

left
right
downward

Question 8

Lead _____ which has its positive electrode to the upper right (right arm) is _____ since all forces are away from it leftward and downward

Answer 8

aVR

negative

Question 9

Indicate if Pos or Neg:
Leads I and II are ________.
Leads V1 and V2 are mostly ______

Answer 9

• positive because forces are going towards their positive electrodes on the left arm and left leg respectively
• negative because predominant forces are away from the right ventricle.

Question 10

Which degrees are referred to as a left axis deviation (LAD)?
Right axis deviation (RAD)?

Answer 10

-30°to -90°is

+90 to +180

*note the normal QRS axis is defined as ranging from -30°to +90°.

Question 11

Normal axis is ______ in both leads I and II

Left axis is ______ in lead I and ______ in lead II

Right axis is _____in lead I and ______ in lead II

Indeterminate axis is _____ in both leads I and II

Answer 11

positive

positive, negative

negative, positive

negative

Question 12

What does the P wave look like in RA enlargement?

Answer 12

In lead II you see a spike in initial P wave that dominates

or

Lead V1, the second half of the p wave is inverted with a smaller hump than if it was LA enlargement

*note: Lead II and V1 are good leads to look at the p-wave for abnormalities:

Question 13

What does the P wave look like in LA enlargement?

Answer 13

In lead II you see a spike in second half of the P wave that dominates

or

Lead V1, the second half of the p wave is inverted with a more prominent hump than RA enlargement

*note: Lead II and V1 are good leads to look at the p-wave for abnormalities:

Question 14

Rt sided leads

Answer 14

V1, V2

Question 15

Lft sided leads

Answer 15

I and V6

Question 16

In Right bundle branch block, what does the QRS look like in right and left sided leads?

Answer 16

Widened QRS

Upright (positive) in rt-sided leads (V1 and V2):
- rSR’ “rabbit ears

Downward deflection(negative) in lt-sided leads (I and V6)
- qRS "S wave"

Question 17

In Left bundle branch block, what does the QRS look like in right and left sided leads?

Answer 17

Widened QRS

Widened QRS away from (downward) V1
rS

and towards (upright) V6
R

Question 18

Hemiblocks what are they and what do they show on the EKG?

Answer 18

(R or L fascicular blocks) cause axis shifts without widening the QRS

*Think about which direction the vectors will flow if the Ant Fasc. is blocked (to the left)

Question 19

LEFT VENTRICULAR HYPERTROPHY

Answer 19

Normal QRS duration with extremely high
voltage especially in V5 and V6
(left sided leads)

Question 20

RIGHT VENTRICULAR HYPERTROPHY

Answer 20

There are large R waves (high voltage) in V1 and V2 (rt sided leads).

Question 21

ANTERIOR VS. INFERIOR
INFARCT LOCATION:
V1-V2
V3-V4
V5-V6
II, III, aVF

Answer 21

V1-V2: anteroseptal wall
V3-V4: anterior wall
V5-V6: anterolateral wall
II, III, aVF: inferior wall

Question 22

High lateral leads
Lateral leads
inferior leads
Anterior leads

Answer 22

High lateral leads: I, AVL
Lateral leads: V5, V6
Inferior leads: II,III,aVF
Anterior leads: V2, V3

(*note: anteroseptal leads consists of V1, V2, V3, V4

• Septal: V1, V2
• Anteroapical: V4, V4)

Question 23

ACUTE INFERIOR MI

?

Answer 23

ST elevations and Q waves in inferior leads (II,III,aVF)
Reciprocal ST depressions in anterior leads (V2, V3)

• note: Order of seeing stuff for MI on an EKG:
  1. Hyperacute T waves
  2. ST elevations
  3. Q waves

Question 24

ACUTE ANTERIOR MI

?

Answer 24

ST elevations and Q waves in anterior leads (V1-V4)

• note: Order of seeing stuff for MI on an EKG:
  1. Hyperacute T waves
  2. ST elevations
  3. Q waves

Question 25

ACUTE PERICARDITIS

Answer 25

Diffuse ST elevations in multiple leads:

No localization

Question 26

Name that abnormality:
Tall P (>2.5 mm in an inferior lead =Rt. atrial enlargement)
Wide notched P wave with late negativity in V1= ??

Answer 26

Lt. atrial

enlargement

Question 27

Name that abnormality:
1. QRS wide?  ≥ .12 secs usually \_\_\_\_\_
2. QRS right axis shift? 
3. QRS left axis shift?
\_\_\_
4. QRS waves?

Answer 27

1. ( ≥ .12 secs usually bundle branch block)
2. (Right axis - ?RVH or posterior hemiblock)
3. (Left axis - ?LVH or anterior hemiblock
4. Infarct usually

Question 28

Name that abnormality:
ST elevation?
ST depression?

Answer 28

elevation: injury if localized or pericarditis if diffuse

depression: ischemia or subendocardial infarct

Question 29

Name that abnormality:
T inversion?
Long QT?

Answer 29

T inversion? (ischemia or 2ndary to hypertrophy)

Long QT? (consider electrolyte imbalance, drug effect)