ECG Flashcards

1
Q

What is the standard paper speed?

A

25 mm/sec. Big boxes equal .2 seconds (5/sec) while each little box is .04 seconds (1500/min).

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2
Q

What is the normal PR interval?

A

3-5 small boxes. .12 - .2 seconds. It is the duration from the beginning of the P wave to the beginning of the QRS complex.

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3
Q

What is the normal QRS interval?

A

Less than 3 small boxes. Less than .12 seconds.

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4
Q

In what position do you have a patient when performing an ECG?

A

Supine and at rest

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5
Q

What are the precordial leads? Where are they placed?

A

They are the leads in front for the heart. They are V1-V6. V1 is placed on the right side of the sternum and V2 on the left both at the level of 4th intercostal space. V3 and V4 are in the 5th intercostal space and V4 is in the mid clavicular line. V5 and V6 are in the 6th intercostal space and V6 in the mid axillary line.

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6
Q

When do you get and isoelectric spike?

A

When the direction of current is exactly perpendicular to the lead.

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7
Q

What does lead 1 record? Which end is positive and which is negative?

A

It is the difference between the right and left arm. The right is negative and the left positive.

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8
Q

What does lead 2 record? Which end is positive and which is negative?

A

It is the difference between the right arm and the left leg. The right is negative and the left positive.

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9
Q

What does lead 3 record? Which end is positive and which is negative?

A

The difference between the left arm and the left leg. The left arm is negative and the left leg is positive.

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10
Q

The limb leads record in these directions ______ while the precordial leads record in these directions _______ together they form _______?

A

The limb leads record from top to bottom and right to left while the precordial leads record from front to back together they form 3D image of the heart electrical activity?

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11
Q

If the patient looks dead in lead II what is the likely problem?

A

The right arm and right leg leads were reversed.

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12
Q

If everything in lead 1 is upside down what is the likely error?

A

The right arm and left arm leads were reversed.

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13
Q

What is the standard of measurement for mV?

A

10 small boxes is 1mV or each small box is .1 mV.

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14
Q

What is a QT interval? What is normal?

A

It is from the beginning of the QRS interval to the end of the T wave. Normal is 350 - 440 msec or 8-11 small boxes.

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15
Q

How do you calculate heart rate on an ECG? What is the formula?

A

It is 1500 divided by the number of small boxes.

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16
Q

What is a normal frontal plane (normal axis)?

A

An axis between -30 and +90 degrees.

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17
Q

What is LAD?

A

Left axis deviation. Plane between -90 and -30

18
Q

What is RAD?

A

Right axis deviation. Plane between +90 and +180

19
Q

aVF is what axis degree? aVL is what axis?

A

aVF is +90. aVL is -30.

20
Q

What is IV conduction? What is AV conduction?

A

IV conduction is the conduction through the inter ventricular septum and it is determined by the QRS interval. AV conduction is the conduction through the AV node and it is determined by the PR interval. QT/square root of the RR interval is the QTc interval it should be less than .45 seconds

21
Q

What is format for reporting an ECG?

A

Rhythm, Rate, Axis, Intervals (IV, AV conduction and Qt)

22
Q

What determines sinus rhythm?

A

P waves that are regular. Upright P waves in leads I and II. A rate between 60 and 100.

23
Q

What are the characteristics of a Right bundle branch block?

A

A wider QRS complex than normal. V1 shows a rSR’. V6 shows qRS. Late upward deflections in right sided leads V1, aVR. Late downward deflections in left sided leads 1, V6

24
Q

What are the characteristics of a Left bundle branch block?

A

A wider QRS complex than normal. V1 shows rS. V6 shows R. Also look for notching in these leads. Late upward deflections in left sided leads 1, aVL, V6. Late downward deflections in right sided leads V1

25
Q

The shape and the level of the ST segment are very important, describe what shows the possibility of an acute MI?

A

ST elevation and a convex curve to the shape (if you can draw a sad face with the wave). If the curve is concave (you can draw a happy face) then they might not be having an MI.

26
Q

What are the differences in the electrical activity between a person have an MI and normal cardiomyocytes?

A

An ischemic or infarcting cell has a less negative resting potential and a slower upshoot with a shorter recovery time.

27
Q

Know the evolution of the ST segment changes in STEMI

A

The Q wave is gone in the beginning and then there is ST elevation. Eventually the Q wave comes back and the ST elevation persists. Then the T wave becomes inverted and finally it can return to normal. Need to see this in contiguous leads.

28
Q

What are the lateral leads?

A

Lead I, aVL, V5, V6

29
Q

What are the anterior/ septal leads?

A

V1, V2, V3, V4

30
Q

What are the inferior leads?

A

Lead II, III, and aVF

31
Q

When does a Q wave show a prior MI?

A

If they are 1 box deep, 1 box wide, and 1/3 the QRS height in contiguous leads.

32
Q

For an MI the order we should know is?

A

Hyperactue T wave, ST segment elevation, Q wave.

33
Q

Which lead is not contiguous with any other?

A

aVR. For this reason it is not as important as the others.

34
Q

What are segments?

A

They are sections in between waves. (they are smaller than intervals.

35
Q

What is first degree heart block (note: heart block is a delay or defect)?

A

It is prolongation of the P-R interval only.

36
Q

What is second degree heart block?

A

Some but not all beats are conducted. There is Mobitz type 1 (Wenckebach) and Mobitz type 2.

37
Q

What is Mobitz type 1 heart block?

A

Gradually increasing PR interval until a P wave is not conducted. The following P wave is conducted with a shorter PR interval. The delay is in the AV node and this is not a serious matter.

38
Q

What is Mobitz type 2 heart block?

A

Sudden non-conducted P waves with no change in PR intervals. This is very unpredictable and dangerous.

39
Q

What is third degree heart block?

A

It is complete heart block in which no P waves are conducted. The ventricle is actually activated by somewhere else in the heart.

40
Q

If there is V-tachycardia with a narrow QRS complex what is the likely origin?

A

Supraventricular origin, intact IV conduction

41
Q

If there is V-tachycardia with a wide QRS complex what is the likely origin?

A

Supraventricular rhythm with aberrant IV conduction (RBBB or LBBB). Ventricular tachycardia.

42
Q

Why is V-tach deadly?

A

It can result in V-fib