BMS 81100 - Physiology > Electrocardiogram I > Flashcards

Electrocardiogram I Flashcards

(44 cards)

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1
Q

How does an electrocardiogram work?

A

It measures the body’s surface electrical potentials which reflect the heart’s electrical activity

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2
Q

What is an electrocardiograph?

A

It is the voltameter that records voltage fluctuations

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3
Q

What is an electrocardiography?

A

It is the process of recording and interpreting the ECG

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4
Q

Why would we want to use an ECG?

A
  1. Determine heart rate and rhythm
  2. Detect arrythmias
  3. Evaluate waveforms
  4. Detect chamber enlargement
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5
Q

In a normal sinus rhythm, Every ________ is followed by a _________, and every ________is preceded by a ________

A

Every P wave is followed by a QRS complex.
Every QRS complex is preceded by a P wave

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6
Q

Main difference between intervals and segments?

A

Intervals (PR, QT) include the waves
Segments (PR, ST, TP) do not

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7
Q

During an ECG, the patient is placed in ___________ recumbency

A

right lateral

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8
Q

Where are the different electrodes placed on an animal?

A

Both forelimbs and left hindlimb.
***Control goes on right hindlimb

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9
Q

Cardiac depolarization and repolarization generate electrical vectors with _________ and _________

A

direction and magnitude

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10
Q

When a vector moves toward a positive electrode, the ECG shows _________

A

an upward (positive) deflection

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11
Q

When a vector is perpendicular to the lead, the ECG shows ____________

A

an isoelectric (flat) line

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12
Q

What is an electrode?

A

A sensor that detects electrical voltage

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13
Q

What is a lead?

A

The voltage difference between two electrodes

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14
Q

How many leads are there?

A

10 leads in total
A. Three limb leads
B. Three augmented leads
C. Four chest leads

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15
Q

Electrodes form _________ triangle

A

Einthoven’s triangle

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16
Q

What does Lead I measure?

A

voltage between right arm (-) and left arm (+)

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17
Q

What does Lead II measure?

A

voltage between right arm (-) and left hindlimb (+)

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18
Q

What does Lead III measure?

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A

voltage between left arm (-) and left hindlimb (+)

19
Q

P wave is positive on which leads?

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A

Lead I, II, and III

20
Q

What does Lead aVR measure?

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A

voltage of right arm (+) compared to average of left arm/left hindlimb

21
Q

What does Lead aVL measure?

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A

voltage of left arm compared to average of right arm/left hindlimb

22
Q

What does Lead aVF measure?

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A

voltage of left hindlimb (foot) compared to average of left/right arm

23
Q

In a normal ECG, all waves in augmented lead _____ are negative

24
Q

In a normal ECG, all waves in augmented lead _____ are positive

25
What does P wave represent?
Atrial depolarization. The left atrium becomes positive relative to right atrium
26
What does Q wave represent?
Early ventricular depolarization (interventricular septum depolarization). Left to right.
27
What does R wave represent?
Ventricular depolarization. Right to left.
28
What does S wave represent?
Late ventricular depolarization. The left forelimb returns to zero then becomes slightly negative.
29
What does the ST segment represent?
It represents the plateau of the AP
30
P wave duration correlates with conduction time through the ________
atria
31
Increased P wave amplitude suggests _______________________
right atrial englargment
32
Increased P wave duration suggest _____________________
left atrial enlargement
33
What is the PP interval?
It is the time between successive atrial depolarizations, it can be used to calculate heart rates
34
What is the PR interval?
the time from onset of atria depolarization to the onset of ventricle depolarization
35
What does a prolonged PR interval suggest?
problems with AV node conduction
36
What does a larger amplitude R wave suggest?
left ventricular enlargement
37
What does a deeper S wave suggest?
ventricular enlargement
38
What does a prolonged QRS duration suggest?
bundle branches block OR enlarged ventricles
39
What affects the T wave duration?
1. Altered Ca and K concentrations in the blood 2. Conduction abnormalities in AV bundle branches
40
What do abnormalities in ST segment suggest?
myocardial injury
41
On an ECG, what are the two paper speeds?
25 mm/second and 50 mm/second
42
On an ECG, the vertical calibration is standardized at 1 mv = ___ mm
10 mm
43
If R-R interval is 0.8 seconds, what is the heart rate?
75 beats/min
44
If the heart rate is 90 beats/min, what is the cycle length?
0.67 seconds
BMS 81100 - Physiology
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