Diagnostic Features of the EKG

Question 1

Qtc Equation?

Answer 1

Qtc = QT/ sqrt(RR)

Question 2

Cause of the P wave

Answer 2

Atrial Contraction

Question 3

Cause of the PR interval

Answer 3

index of conduction time across the AV node

Question 4

PR Interval Length

Answer 4

0.12 - 0.20 seconds

Question 5

Q-Tc Interval

Answer 5

Less than 0.44 s

Question 6

Light Lines on EKG represent what amount of time?

Answer 6

0.04 Seconds

Question 7

Heavy Lines on EKG represent what amount of time?

Answer 7

0.2 Seconds

Question 8

Heart Rate Equation from EKG

Answer 8

HR = 300 / # heavy lines between 2 QRS’s OR HR = 1500 / # mm between 2 QRS’s

Question 9

Positive Deflection results from?

Answer 9

Depolarization moving towards a positive electrode

Question 10

QRS will be upwards in which leads?

Answer 10

Left and Lateral Leads

Question 11

QRS will be downwards in which leads?

Answer 11

Right

Question 12

of Bipolar Leads and Locations?

Answer 12

3 Total. I, II, III. They are located on the right and left arms, and the left foot/leg.

Question 13

Lead II direction of positivity?

Answer 13

Right hand (negative) towards left foot (positive)

Question 14

Lead I direction of positivity?

Answer 14

Right hand (negative) towards left hand (positive)

Question 15

Lead III direction of positivity?

Answer 15

Left hand (negative) towards left foot (positive)

Question 16

Augmented Limb Leads?

Answer 16

aVR (augmented right hand), aVL (left hand), and aVF (left foot)

Question 17

Precordial Leads

Answer 17

V1 - V6.

Question 18

aVR Deflection Direction? Positive, Negative or both?

Answer 18

Directionality from heart towards RAISED right hand produces a completely negative EKG. (p, qrs and t all negative)

Question 19

II, III and AVF are all referred to as…?

Answer 19

Inferior Leads. Give information about the inferior wall of the heart. Damage to this region would best be seen in these leads.

Question 20

I and AVL are referred to as….?

Answer 20

Lateral Leads. Lateral infarcts in the upper/higher portion of the left ventricle would be seen here.

Question 21

Note: Almost all infarcts occur in the left ventricle.

Answer 21

This means you, Soliman.

Question 22

V1 Location

Answer 22

Right Sternal Border. Near SA node. Shows right ventricular Abnormalities and septum.

Question 23

V2 Location

Answer 23

Left Sternal Border. Also looking at right side of the heart. Shows right ventricular Abnormalities and septum.

Question 24

V3 Location

Answer 24

Left Sternal Border below V2. Shows septal defects and a portion of the left ventricular free wall.

Question 25

V4

Answer 25

Below Pec Major in 4th intercostal space. Shows septal defects and a portion of the left ventricular free wall.

Question 26

V6

Answer 26

Placed Lateral to V5 in 4th intercostal space. Left ventricular lead.

Question 27

What is the plane of the precordial leads?

Answer 27

Horizontal Plane. Take a “slice” of the heart.

Question 28

V5

Answer 28

Below Pec Major in 4th intercostal space. Exclusively left ventricular lead.

Question 29

Ventricular Hypertrophy EKG

Answer 29

Increased Volts/Amplitude of QRS complex in certain leads.

Question 30

Left Ventricular Hypertrophy Leads

Answer 30

Big R Waves in left sided leads (I, aVL, V5 and V6)

Question 31

Right Ventricular Hypertrophy Leads

Answer 31

Big R Waves in right sided leads (V1 and V2)

Question 32

Ischemia Definition

Answer 32

Insufficient blood supply to meet demands (in the ventricles)

Question 33

Ischemia EKG Effects

Answer 33

• Depression of the ST segment (Due to inc O2 demand in face of fixed coronary obstruction)
• T Wave Inversion (due to acute coronary artery obstruction during low O2 demand)

Question 34

ST elevation is usually due to…?

Answer 34

Current Transmural Injury (Infarction)

Question 35

Sign of Past Infarction?

Answer 35

Q wave on a completely R positive lead.

Question 36

Significant Q Wave Definition

Answer 36

1) Greater than 1/4 the amplitude of the R wave
2) One small box wide (0.04 seconds)
3) Seen in usually at least 2 leads reflecting the same region of the left ventricle.

Question 37

Transmural Myocardial Infarct Progression on EKG

Answer 37

1) Peaked T-Wave (rare and short)
2) T-Wave Inversion (no damage yet)
3) ST Elevation (injury has occurred)
4) Q-Wave, ST-Elevation, T-Inversion (seen all together- too late!)

Question 38

Subendocardial Infarct causes what on the EKG?

Answer 38

ST Depression… NO Q WAVE!

Question 39

Infarct Location if seen in V1-V2?

Answer 39

Infarct in Anterospetal Wall

Question 40

Infarct Location if seen in V3-V4?

Answer 40

Infarct in Anterior Wall

Question 41

Infarct Location if seen in V5-V6?

Answer 41

Infarct in Anterolateral Wall

Question 42

Infarct Location if seen in II, III, aVF?

Answer 42

Infarct in Inferior Wall

Question 43

Infarct Location if seen in I, aVL?

Answer 43

Infarct in High Lateral Wall

Question 44

Prolonged QT interval Definition

Answer 44

QT Interval is longer than half of the R-R interval

Question 45

Causes of Long QT

Answer 45

Hypocalcemia, hypokalemia, hypomagnesemia
Class 1A or 3 Anti-arrhythmic Drugs
Hypothermia
Congenital Long QT Syndrome

Question 46

Hypokalemia EKG

Answer 46

Flattened T Wave with Presence of merging with U wave. Long QT interval!

Question 47

Hypercalcemia EKG

Answer 47

Shortened QT interval!

Question 48

Hyperkalemia EKG (3 stages)

Answer 48

5. 5-7.5 (mmol/L) - Tall T Waves (peaked and symmetrical)
6. 5-9.0- P&R waves flatten, QRS&T broaden and big S Waves develop
7. 0+ - P&R waves gone, S&T Waves Broaden in a sine wave pattern

Question 49

Hyperkalemia Treatment

Answer 49

Is an acute emergency that can be treated with insulin (among other things).