Chapter 11

Question 1

Things to look for in the QRS

Answer 1

Amplitude
Width
Morphology
Q waves
Axis along frontal plane
Z axis (transition zone)

Question 2

Three things that lower amplitude

Answer 2

Obesity, amyloid deposits in hypothyroid patients, effusion

Question 3

Low voltage criteria

Answer 3

Less than 5mm in limb leads, less than 10mm in precordial. Remember in obese or emaciated patients precordial leads may be more effected

Question 4

Two causes of LVH

Answer 4

High afterload the ventricle needs to fight against or volume overload such as a leaking valve allowing blood back into the left ventricle

Question 5

Criteria for LVH

Answer 5

1. Deepest S wave of V1 or V2 plus R wave in V5 or V6, total greater than or = to 35mm
2. Any precordial lead greater than 45mm
3. R wave in aVL is greater than or equal to 11mm
4. R wave in lead I is greater than or equal to 12mm
5. R wave in lead aVF greater than or equal to 20mm

Question 6

RVH criteria

Answer 6

RAE indicates RVH

V1 or V2 R:S ratio greater than one (strain pattern if it is associated with a flipped T)

Question 7

Differential for widened QRS (8 of them)

Answer 7

Hyperkalemia
V tach
Idioventricular rhythms including heart block
Drug effects and ODs (especially TCAs)
WPW
Bundle branch block and intraventricular conduction delay
Premature ventricular contractions
Aberrantly conducted beats

Question 8

Septal Qs are found in

Answer 8

I and aVL

Question 9

QS waves found in V1

Answer 9

If isolated to that lead are benign if they extend through V2 or especially V3 they are significant

Question 10

Q waves isolated to III

Answer 10

benign

Question 11

Respiratory variation of Q waves

Answer 11

Patients with abdo distention (ascites, preggos, obesity) have a heart which lies along the horizontal plane. When they breath and the diaphragm flattens the heart gets pulled more vertical, which extends the depth of the Qs

Question 12

Q waves are significant if

Answer 12

1mm wide
2mm deep
25% (or 1/3) depth of QRS or greater than 45mm
normally significant if found in V1 V2 V3

Question 13

Transition zone

Answer 13

Normally between v3 and v4.

If it is before V3 it is referred to as counter clockwise rotation, after V4 clockwise rotation.