Enlargement and Hypertrophy

Question 1

What should the maximum height of a p-wave be?

Answer 1

2.5 milivolts (2.5 small boxes)

Question 2

What two leads can help you look for atrial enlargement?

Answer 2

II and V1

Question 3

Why is lead II helpful in looking for atrial enlargement?

Answer 3

Oriented nearly parallel

Question 4

Why is lead V1 helpful in looking for atrial enlargement?

Answer 4

Oriented nearly perpendicular

Question 5

What would you look for to diagnose right atrial enlargement on EKG?

Answer 5

The positive P wave in II would be greater than 2.5 boxes in amplitude and the positive portion of the P wave in V1 would greatly out do the negative portion.

Question 6

What EKG findings will you diagnose left atrial enlargement

Answer 6

1. In V1, the terminal portion will be more than 1 small box negative
2. In lead II, the second portion of the P wave will be spiked and greater than 2.5 boxes in amplitude
3. The terminal portion of the P wave will be widened > 1 small box (0.04 seconds)

Question 7

Does right atrial enlargement change the duration of the P wave?

Answer 7

No. Any lengthening of this portion is hidden by the terminal portion of the P wave from left atrial depolarization.

Question 8

What must the axis be to diagnose RVH?

Answer 8

> 100 degrees (QRS in I must be more negative than positive)

Question 9

What might you expect to find in the precordial leads for RVH?

Answer 9

Large R waves in V1 and small R waves in V5-6. This is because V1 which overlies the RV is overlying the hypertrophied muscle, where as the left ventricle while normal sized is now electrically humble.

Question 10

What is the criteria for LVH that combines V1 or V2 plus V5 or V6

Answer 10

The R wave amplitude in V5 or V6 plus the S wave amplitude in V1 or V2 should be greater than 35

Question 11

What is the criteria for LVH in V5?

Answer 11

R wave amplitude > 26 mm

Question 12

What is the criteria for LVH in V6?

Answer 12

R wave amplitude > 18

Question 13

What is the criteria for LVH that combines V5 and V6?

Answer 13

If the R wave amplitude is greater in V6 than V5 LVH is more likely

Question 14

Below what age is the criteria for LVH poor?

Answer 14

Less than 35. These EKG findings are common in this age range due to relatively thin chest wall.

Question 15

What is the criteria for LVH in aVL?

Answer 15

R wave amplitude > 13 mm

Question 16

What is the criteria for LVH in aVF?

Answer 16

R wave amplitude > 21 mm

Question 17

What is the criteria for LVH in I?

Answer 17

R wave amplitude > 14 mm

Question 18

What are secondary repolarization abnormalities associated with LVH?

Answer 18

1. Down sloping ST segment

2. T wave inversion

Question 19

If you have a patient with LVH that now has secondary repolarization abnormalities, what does this often signify?

Answer 19

There is now ventricular dilation along with the hypertrophy

Question 20

What is the sensitivity and specificity of LVH criteria on an EKG?

Answer 20

It’s only 50% sensitive but nearly 90% specific

Question 21

What are the classic EKG findings for HCM?

Answer 21

1. Ventricular hypertrophy
2. Repolarization abnormalities in those leads with the tallest R waves
3. Q waves, of uncertain etiology, in the inferior and lateral leads

Question 22

Why can verapamil be used for HCM?

Answer 22

reduces the strength of ventricular contraction, thereby decreasing the obstruction from the hypertrophied muscle, and improves the compliance of the stiffened ventricle.

Question 23

Why are beta blockers used for HCM?

Answer 23

lessen the risk for significant ischemia and may prevent arrhythmias.