ECG

Question 1

Lead systems

Answer 1

-Two wires(with a 3rd ground wire to reduce noise)
-records the very small voltage-differences between different spots of the myocardium

Question 2

Using more pairs of wires allows us to

Answer 2

view the electrical events from a different 3D angles or perspectives/vantage point

Question 3

ECG analysis is of

Answer 3

HR & rhythm analysis

Question 4

What spot of the heart is the genesis of each heartbeat, electrically?

Answer 4

SA (sinoatrial) Node

Question 5

Which wave does Atrial depolarization occur?

Answer 5

P wave

Question 6

In which wave does Ventricular depolarization occur?

Answer 6

QRS complex

Question 7

In which wave does Ventricular repolarization occur?

Answer 7

T-wave

Question 8

Which wave is a negative
deflection?

Answer 8

Q wave

Question 9

Which wave is a positive deflection?

Answer 9

R Wave

Question 10

Which wave is a negative
deflection (after an R wave)?

Answer 10

S wave

Question 11

T-wave are highly _______

Answer 11

variable; meaning they could be positive, negative etc.

Question 12

Hard rules of T waves

Answer 12

• They must exist
• They must follow the QRS

Question 13

Potential concern of T waves

Answer 13

-Abrupt major change in T wave morphology as an isolated finding (no major change in HR or QRS)

-Extremely high-amplitude T waves in many leads

Question 14

T-wave ______ can be lead-dependent

Answer 14

visibility; They might not be
clearly visible on all leads

Question 15

Unlike QRS and T waves, P wave do not have to ______

Answer 15

exist

Question 16

When do P waves occur in relation to T waves and QRS complex?

Answer 16

Normally precede QRS but don’t have to….
* Can occur after the QRS
* Can occur during the QRS
* Can occur randomly with respect to QRS

Question 17

How to identify P waves?

Answer 17

Repetitive “signals” that look like they could be P-waves
* Sometimes occur at regular intervals
* We start by looking for them preceding the QRS
* but need to look everywhere for them
* Usually lower amplitude than QRS
* Rounded tops/bottoms
* “Not” the T-wave
* P and T waves can look similar

Question 18

What could exist that allows for one to predict (look for) additional P waves that might be otherwise hard to find

Answer 18

If there is a fairly constant P- P interval, you use that

Question 19

Intervals refer to

Answer 19

These refer to findings between the any of the 3 major elements (P, QRS, T)

Question 20

Segments are

Answer 20

the time between two adjacent elements

Question 21

We look at the _____ of intervals and segments

Answer 21

duration

Question 22

Bigger heart chambers means

Answer 22

Greater voltages
* Highly variable to begin with
* Not always clearly evident
(especially for QRS)

Question 23

Heart Enlargement Pattern for duration

Answer 23

Longer duration for depolarization
* Could be enlargement
* Could also be slower conduction without enlargement

Question 24

3 descriptors for heart rhythm analysis

Answer 24

• A descriptor about heart rate (tachycardia, bradycardia)
• A descriptor about the stimulus source location for the QRS complexes (supraventricular (atrial) or ventricular)
• A descriptor about the regularity of the rhythm

Ex:Irregular supraventricular tachycardia

Regular monomorphic tachycardia

Question 25

True/False; we can confirm the SA node part from a routine ECG

Answer 25

FALSE, we CANNOT

Question 26

What values are seen in a normal sinus rhythm

Answer 26

* Normal heart rate * Normal QRS morphology * Normal P-wave with P-QRS association

Question 27

The process of ECG analysis is a combination of...

Answer 27

* Rules- QRS and T must be present * Logic and Probability - Such and such couldn’t be true, therefor it isn’t true. -Such and such would be extremely unlikely to happen, therefore we first look to alternative, more likely explanations

Question 28

Heart rate usually refers to what rate in ECGs

Answer 28

HR is beats per minute Usually refers to QRS rate * Normally should be same as P wave rate * If not, unless otherwise specified, it’s referring to QRS rate

Question 29

How to take HR manually

Answer 29

Count the amount of QRS complexes in a known time interval and multiple the QRS count by 60 divided by time interval (sec)

Question 30

What to look for as QRS morphology abnormalities?

Answer 30

-Duration -Polarity (Dominantly positive in lead 2) -Shape of the wave * Fast changes in direction * Sharp “single” peaks * No interruptions (esp at beginning))

Question 31

What does Supraventricular or Ventricular mean?

Answer 31

Is the beat Supraventricular or Ventricular in origin

Question 31

The either/neither test

Answer 31

Either is true (supraventricular) * QRS has an associated preceding P wave * QRS morphology is normal * Neither is true (ventricular)

Question 32

?s to ask for P-wave analysis

Answer 32

Do you see them? Do they normal and basically the same? * Could you see them if they are there? * Is every P-wave followed by a QRS? If no, probably AV block of some kind * Is every QRS preceded by a P? If no, become suspicious for a beat of ventricular origin (check QRS morph), or atrial arrest, or atrial fibrillation