EKG basic rules

Question 1

P wave amplitude > 2.5 mm in at least one of the inferior leads allows you to diagnose what?

Answer 1

Right atrial enlargement

Question 2

How do you diagnose left atrial enlargement?

Answer 2

1) 2nd portion of P wave incr. amplitude:
In V1, terminal P wave drops > 1 mm below baseline, and no axis deviation seen
OR
Incr. in duration:
2) terminal portion of P wave at least 1 small box (0.04 sec) in width in lead 2

Question 3

Which tends to occur first, atrial enlargement or ventricular hypertrophy?

Answer 3

Ventricular hypertrophy

Question 4

What are the criteria for left ventricular hypertrophy (LVH)? (important)

Answer 4

1) R wave in V5 or V6 + S wave in V1 or V2 exceeds 35mm
2) R wave in aVL is 11mm
3) R wave in aVL + S wave in V3 exceeds 20mm in women and 28mm in men

4) LAD > ~15 degrees, but not useful diagnostic feature, & QRS may be slightly prolonged

Question 5

What 2 leads do you need to look at for RVH?

Answer 5

V1 and V6

Question 6

Which is normally due to afterload (pressure overload), hypertrophy or enlargement?

Answer 6

Hypertrophy

Question 7

AFIB:
1) Does AFIB have true P waves?
2) Is QRS wide or narrow?

Answer 7

1) No
2) Narrow

Question 8

1) What is the rate of MAT?
2) What is the rate of PAT?
3) Do they have P waves?

Answer 8

1) 100-200 (can be <100) (irregular)
2) 100-200
3) Yes (may not be visible in PAT)

Question 9

Differentiate between the types of premature beats

Answer 9

Question 10

How can you remember Mobitz type 2 second degree AV block?

Answer 10

“If some don’t get through, then you have a Mobitz 2”

Question 11

How can you remember first degree AV conduction blocks?

Answer 11

“If R is far from P, then you have a first degree”

Question 12

Describe what a normal p wave looks like

Answer 12

1) Amplitude small; normally does not exceed 2.5 mm (2.5 small boxes) or 0.25 mV
2) Usually most positive in lead 2 and most negative in lead aVR
-Individual patients vary so “typical” may not apply
3) Normal range of P vector = 0 – 70 degrees

Question 13

List some main characteristics of right BBB

Answer 13

1) RBBB
2) Wide QRS complex
3) RSR’ V1 and 2 (or just tall R waves)
4) Left lateral leads with late deep S wave

Question 14

List the main characteristics of left BBB

Answer 14

1) Broad or notched R wave in left lateral leads
2) Deep S wave in leads over RV
3) May see Left Axis deviation

Question 15

Abnormality of repolarization in ______ results in depressed ST segments and flipped T waves

Answer 15

BBB

Question 16

ST and T wave changes:
1) Where are they seen in RBBB?
2) What abt LBBB?

Answer 16

1) RBBB – in leads V1-3 (similar to LVH with repole abnormality)
2) LBBB- left lateral leads

Question 17

What is the major effect of hemiblocks on an EKG?

Answer 17

Cause axis deviation

Question 18

List the criteria for hemiblocks

Answer 18

Question 19

List the criteria for right and left BBBs

Answer 19

Question 20

List 3 main findings in WPW

Answer 20

1) Short PR interval
2) Delta wave
3) Wide QRS