Chapter 15-Basic 12-Lead ECG Interpretation

Question 1

identify the lead that is used to diagnose problems with the lateral wall of the left ventricle

Answer 1

Leads I, aVL, V5 & V6

Question 2

identify the lead that is used to diagnose problems with the anterior wall of the left ventricle

Answer 2

Leads V3 & V4

Question 3

identify the lead that is used to diagnose problems with the septal wall

Answer 3

Leads V1 & V2

Question 4

identify the lead that is used to diagnose problems with the inferior wall of the left ventricle

Answer 4

Leads II, III, aVF

Question 5

List the five steps used to interpret ECG

Answer 5

1. determine rhythm or regularity
2. determine atrial and ventricular rate
3. identify P wave morphology
4. measure PR interval
5. measure QRS complex and morphology

Question 6

step 6 signs of ischemia or injury: delay in repolarization is represented by:

Answer 6

ST segment depression or elevation

Question 7

define myocardial ischemia

Answer 7

reduction or interruption in blood flow and oxygen to myocardium for short period of time

Question 8

define anatomically contiguous lead

Answer 8

two or more leads looking at same part of heart, or numerically consecutive chest leads

Question 9

identify three examples of anatomically contiguous leads

Answer 9

II+III, III+aVF
I+aVL
V1+V2, V2+V3, V3+V4, V4+V5, V5+V6

Question 10

describe three indicators of ischemia

Answer 10

-ST segment depression of 1mm or more when seen in two or more anatomically contiguous leads
-T wave inversion
ST segment depression or elevation

Question 11

define myocardial injury

Answer 11

injury to cardiac muscle caused by prolonged reduction or interruption of blood flow

Question 12

Step 7 sign of infarction: describe a normal or physiologic Q wave

Answer 12

normal Q wave, measuring less than 0.04 second in duration and less than 1/3 height of R wave in that lead

Question 13

Describe a pathologic Q wave

Answer 13

Q wave that measures 0.04 seconds or wider in duration and/ or is 1/3 or more height of R wave in that lead

Question 14

define axis deviation

Answer 14

changes that occur on 12-lead ECG due to orientation or position of heart within chest

Question 15

due to an abnormal heart location, what QRS changes occur

Answer 15

deflection of QRS complex

Question 16

list 3 causes of heart displacement from its normal location

Answer 16

-pregnancy
-birth defects
-left ventricular hypertrophy

Question 17

define hypertrophy

Answer 17

abnormal thickening of ventricular wall due to chronic pressure overload, often caused by hypertension

Question 18

describe the leads that are used to determine the presence of axis deviation

Answer 18

Leads I and aVF

Question 19

describe the changes that occur to the heart with left ventricular hyhpertrophy

Answer 19

thickening of ventricular wall due to chronic pressure overload

Question 20

describe the changes to the ECG when left ventricular hypertrophy exists

Answer 20

greater amplitude of QRS complex