ECG Flashcards

1
Q

P wave

A

First short upward movement of the EKG tracing.

  • atrial depolarization: It indicates that the atria are contracting, pumping blood into the ventricles.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The QRS complex

A

Normally beginning with a downward deflection, Q; a larger upwards deflection, a peak (R); and then a downwards S wave.

  • The QRS complex represents ventricular depolarization and contraction, emptying the ventricles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

PR interval

A

indicates the transit time for the electrical signal to travel from the sinus node to the ventricles.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

T wave

A

normally a modest upwards waveform, representing ventricular repolarization and relaxation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How do you calculate accurate HR using an EKG?

A

Count the number of large squares from R peak to R peak, and divide that by 300.
- ie: 300/5 = 60

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How many squares = 1 second?
How many large squares = 6 seconds?
How many seconds does 1 large square =?
How many seconds does 1 small square =?

A

5 large squares
30 large squares = 6 seconds
1 large square = 0.2 sec
1 small square = 0.04 sec

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

In individuals with irregular heart rates, how do you measure an accurate heart rate?
- what if there are 7 R waves found in that interval, how many beat in 1 min?

A

Count 30 large squares (6 seconds) and then count how many R waves are found in the 30 large squares.

7 beats in 6 seconds

  • There are 60 seconds in 1 min
  • There are 70 beats in 1 min
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In a normal heart, the time between the onset of atrial depolarization (beginning of P wave) and the onset of ventricular depolarization (beginning of QRS complex) normally varies between what time frame?

A

PR interval = 0.12s - 0.2s
or 3 - 5 small squares

  • many imp disorders are associated with alterations in the PR interval
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The PR interval is largely determined by what?

A

physiological delay of the depolarization wave in the AV node and transit in the bundle of his.

  • many imp disorders are associated with alterations in the PR interval
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The QRS interval duration is largely determined by what? What is the width of the QRS interval typically?

A

time taken for ventricular depolarization to be completed.

Normally less than or equal to 3 small squares
no more than 3 ss!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

QT interval

- how many squares is it usually?

A

Time between the onset of ventricular depolarization and the end of the ventricular repolarization (beginning of QRS complex and end of T wave)

Normally less than 11 ss at a heart rate of 60 beats per min.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Does the QT interval expand or decrease as the heart rate speeds up?

A

QT interval gets shorter as heart speeds up

  • at higher heart rates, possible to miss underlying prolonged QT interval
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

If you find that QT interval is 8 ss, how many seconds is that?

A

0.32 seconds

1 small square = 0.04 sec
8 small squares = 0.32 sec

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Corrected QT interval = ?

A

QT / squareroot(RR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Ventricular depolarization

A

“ventricular systole”

Coordinated transmission of stimulus (cation flows) leading to contraction of the ventricles.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Ventricular repolarization

A

Last event of the cycle.
Restoring of the resting state.
Begins with the closure of the slow calcium channels and opening of the potassium channels.

  • Repolarization proceeds from the apex of the heart to the base of the heart.