The Electrocardiogram Flashcards

1
Q

There are 3 bipolar leads which are derived from two electrodes. What are they?

A

Leads I-III

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2
Q

The unipolar leads are derived from an electrode and Wilson’s Central Terminal. What are they?

A

V1-V6, aVL, aVR, and aVF

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3
Q

In an EKG, each small box is

A

0.040 seconds

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4
Q

In an EKG, every 5 boxes equals

A

0.2 second

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5
Q

Beginning of atrial to beginning of ventricular activation

A

PR interval

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6
Q

The normal duration of the PR interval is

A

0.12-0.2 seconds

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7
Q

The normal duration of QRS is

A

Less than 0.12 seconds

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8
Q

Normal conduction down His-Purkinje tissue and through ventricles

A

Normal WRS

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9
Q

What is a normal QT interval?

A

Less than 440ms for men and 460ms for women

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10
Q

How do we calculate corrected QT?

A

QTc = QT / square root of RR interval

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11
Q

Quick estimate of rate in an EKG is

A

300/n where n = number of big boxes

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12
Q

Functions as a natural pacemaker and initiates each atrial contraction

A

SA node

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13
Q

Strictly speaking, ‘sinus rhythm” refers only to what is happening in the

A

Atrium

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14
Q

Implies that the atrial rhythm originates in the sinus node and there is 1:1 conduction to the ventricle and the rate is 60-100 BPM

A

Normal Sinus Rhythm

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15
Q

A normal P and QRS axis for an EKG is

A

-30 to 90 degrees

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16
Q

What is the quick way to determine normal axis?

A

Lead I positive and lead II positive

17
Q

What is the quick way to see left axis deviation?

A

Lead I positive, lead II negative

18
Q

Right axis deviation is characterized as

A

Lead I negative and AVF positive

19
Q

EXTREME right axis deviation is characterized by

A

Lead I negative and AVF negative

20
Q

MI, left anterior fascicular block, and LVH can cause

21
Q

Widened QRS, RSR’ in V1 (rabbit ears), and prominent S in V6 is characteristic of

22
Q

Widened QRS, broad notches R in V6, and absent R and prominent S in V1 is characteristic of

23
Q

Initial depolarization is normal, septal q-waves are intact, and late forces are upwards and leftwards

A

Left Anterior Fascicular Block

24
Q

Overall QRS is less than 120 ms, RS in II, III, and aVF, and frontal axis is less than 45 degrees

A

Left anterior Fascicular Block

25
Initial depolarization is normal, and late forces are DOWNWARDS and rightwards
Left Posterior Fascicular Block
26
In a left posterior Fascicular Block, the precordial axis is
Rightwards (90-180 degrees)
27
Right atrial enlargement can be see with
1. ) V1 positive deflection of P wave (greater than 1.5 mm) | 2. ) Lead II P wave amplitude is greater than 3 mm (boxes)
28
Characterized by a P wave that is broad (greater than 0.04 secs) in V1 and a P wave in II greater than 0.12
Left Atrial Enlargement
29
RAD w/ prominent R wave in V1 (greater than 7 mm)
RVH
30
Sum of amplitudes of S wave in V1 + R wave in V5 or V6 is greater than 35 mm
LVH
31
Has an aVL R wave greater than 11 mm
LVH
32
Trans mural ischemia shows on an EKG as
ST elevation and Q-waves
33
Non-transmural ischemia is seen on an EKG as
ST depression -Not associated w/ Q waves
34
Has more positive resting potential and shorter AP duration
Ischemic tissue
35
When we see the appearance of new Q waves, we have an
Infarction
36
Shows up anterior, apical, and lateral
Left Anterior Descending artery ischemia
37
Show up on posterior and lateral heart and inferior wall
Circumflex Artery Ischemia
38
Shows in right ventricle and posterior and inferior 80%) heart
Right coronary artery ischemia