Ekg Exam

Front 1

Apex of the heart:

Back 1

is the bottom point of the heart

Front 2

Base of the heart:

Back 2

is the top, flat part of the heart.

Front 3

Endothelial cells:

Back 3

are in all arteries & veins.

Front 4

What is the difference between myocardial and skeletal tissue?

Back 4

Cardiac muscles are involuntary & have enterclated discs and the muscles are intertwined so the muscles can twist.
Skeletal muscles are voluntary & the muscles are parallel to each other.

Front 5

Gap junctions:

Back 5

help with conduction in interclated discs.

Front 6

Cardiac cells:

Back 6

generate their own action potential.

Front 7

Pacemaker cells:

Back 7

SA/AV cells. SA= 60-100 BPM
AV = 40-60 bpm

Front 8

Myocardial cells:

Back 8

calcium

Front 9

Conduction System (cells):

Back 9

Right & Left Bundle Branches, Purkinje fibers, Bundle of HIS, SA & AV nodes

Front 10

Sequence of conduction:

Back 10

action potential originates in the SA node & then travels to the AV node and from there to the Bundle of HIS then to the left & right Bundle Branches & finally to the Purkinje fibers on to the ventricular walls (myocardium)

Front 11

EKG tracings:

Back 11

Amplitude (up & down) = milivolts
large boxes are .2 seconds. 1 large box is 0.5 mV. and 2 large boxes = 1 mV 5 small boxes equal 5 mm. 1 small square is 0.1 mV or or 1 mm. One small square is 0.04 seconds & the distance across a large square is 0.2 seconds

Front 12

Different waves of the heart represent:

Back 12

P wave = atrial depolarization, contraction of the atrium.
There is a pause between the P wave and Q wave because valves separate the atria from the ventricles.
Q wave= depolarization of the septum.
QRS waves or QRS complex represents ventricular repolarization (contraction)
R wave = ventricular contraction
T wave = ventricular repolarization

Front 13

Segments & Intervals:

Back 13

Segments = straight line connecting 2 waves.
Interval = includes at least one wave plus the connecting straight line.

Front 14

Segments & Intervals:

Back 14

PR Segment = end of p wave to beginning of Q wave.
PR Interval = beginning of p wave to beginning of q wave.
ST Segement= end of QRS to beginning of T wave.
ST Interval = QRS & ST segment & T wave.
QRS Interval = beginning of q wave to the end of s wave.

Front 15

Why are wave forms either positive or negative?

Back 15

Negative if depolarization is moving away from the positive electrode.
Positive if repolarization is moving toward the electrode.

Front 16

Leads (Einthoven's Triangle):

Back 16

EKGs generate 12 views of the heart called leads.
Limb leads: right arm & leg & left arm & leg. Give the views of depolarization/repolarization moving up & down and right & left through the frontal plane.
Limb lead electrodes are placed: right & left arm below mid-clavicular, right & left leg is placed mid-clavicular below rib cage.

Front 17

How do we get the augmented leads?

Back 17

Augmented leads are leads that change polarity - bi-polar leads that change from positive to negative. Augmented leads give us more views of the heart.

Front 18

Precordial leads:

Back 18

Provides a horizontal plane view of the heart. View of electrical forces moving anteriorly & posteriorly. Placed across the chest horizontally.
V1 = right sternal border & 4th intercostal space.
V2 = left sternal border & 4th intercostal space.
V4 = 5th left intercostal space mid-clavicular.
V3 = In between V2 & V4
V5 = 5th intercostal space anterior axillary line.
V6 = horizontal to V5 mid-axillary line 5th intercostal space.

Front 19

What is a vector?

Back 19

direction of the the current flow & voltage (amplitude).

Front 20

Normal durations/amplitudes of waves, segments and intervals.

Back 20

P waves: P wave amplitude is usually not more than 0.25mV or 2.5mm = 2.5 small boxes
PR intervals: PR Interval lasts from 0.12-0.2 seconds (3-5 mm)
PR segments: runs along the same baseline as start of the P wave.
QRS Interval: Normal QRS interval is 0.06-0.1 seconds
Q wave: Normal septal waves have an amplitude no more than 0.1mV
T wave: Normal T wave is 1/3 to 2/3 the amplitude (height) of the corresponding R wave.
QT interval: The duration of the QT interval is proportional to the heart rate.

Front 21

Why does the R wave look different in different leads?

Back 21

Because the vector is going away from the electrode.

Front 22

HR methods:

Back 22

one small box = 0.04 seconds. One large box = 0.2 seconds. 5 large boxes = 1 second.
Start with an R wave that begins on a dark line for every following black line count down: 300, 150, 75, 60, 50 and stop at the next R wave = HR range.
Find R wave that peaks on dark line, Count the number of large boxes until the next R wave
Take 300 and divide by that number.
Count the number of small boxes until the next R wave
Take 1500 and divide by that number.

Front 23

What does sinus mean?

Back 23

Originates in the SA node.

Front 24

Normal sinus rhythm:

Back 24

-P waves normal & present.
-Are the QRS complexes narrow or wide?
-What is the relationship between the P waves and the QRS complexes?
-Is the rhythm regular or irregular.

Front 25

What are the different types of sinus rhythms?

Back 25

-Normal sinus rhythm = 60-100 bpm
-Sinus bradycardia = ≤60 bpm
-Sinus tachycardia = ≥100 bpm