CMA ch. 7 - 8

Inner most layer of the heart

endocardium

P wave

PR segment

Q segment

R wave

S wave

ST segment

T Wave

Middle layer of the heart

myocardium

Outermost layer of the heart

epicardium

Upper chambers of the heart

atria

Right atrium receives blood from

the superior and inferior vena cava

Only vein that receives oxygenated blood

pulmonary vein

Only artery that receives deoxygenated blood

pulmonary artery

Right AV valve

tricuspid valve

Left AV valve

bicuspid/ mitral valve

Lubb sound happens when

AV valve closes at the start of systole

Dubb sound happens when

semilunar valve closes at the end of systole

Mediastinum

thoracic compartment where the heart resides

Largest artery in the body

aorta

Blood exits __ side of the body out of the aorta

left

The heart account for ___% of the body’s metabolic demand

25

The heart will beat approximately __ times through a pt’s life

4.8 billion

A healthy heart is regulated by the

sinoarterial node (AV node)

Depolarization

releasing a pulse of electricity

Depolarization will occur in the SA node at a rate of

60 to 100 bpm

If the AV node is acting as the pace maker, it will depolarize at a rate of

40 to 60 bpm

His purkinje system

conducts electricity through the myocardium, allows the heart to beat in the most efficient way

Order of his purkinje system

AV node : bundle of his : bundle branches : purkinje fibers : leads to heart contraction

P waves

Atrial depolarization

PR segment

flatline, no electricity is moving and is caused by the AV delay

QRS complex

sharp deflections

Q wave

depolarization of the septum

R wave

relates to the depolarization of the apex

S wave

depolarization of the left ventricle

ST segment

isoelectric line

T wave

repolarization of the ventricle myocardium

CO

cardiac output, amount of blood being pumped out by the heart multiplied by the heart rate

Apex

the thickest region of myocardial tissue

Valve

A section of fibrous tissue to prevent the backflow of blood in the heart

AV node

resides at the junction of ventricles and atria

Bundle of his

from the av node into the interventricular septum

Bundle branches

carry the action potential through the septum to the purkinje system

Purkinje fibers

penetrate into the myocardium from the sub endo cardial space

How do the electrical signals of the heart relate to the pumping of the heart

depolarization allows for the influx of sodium ions which releases calcium ion stores allowing muscle contraction

When is 12 lead EKG used

outpatient, routine monitoring, at rest

When is telemetry used

inpatient monitoring, produces continuous monitoring

When is the holter monitor used

1 to 3 days outpatient during the commencement of normal everyday living. Used for identifying events that may not be visible in a limited window

Sinus rhythm HR

60 to 100

Sinus rhythm PR

0.12 to 0.20 sec

Sinus rhythm QRS

0.04 to 0.1 sec

Bradycardia

HR less than 60 bpm

Tachycardia

HR greater than 100 bpm

Arrhythmia

an irregular heart rhythm

Atrial rhythms

atrial flutter and atrial fibrillation

How many electrodes in a 12 lead EKG

10 electrodes

12 lead EKG gives __ perspectives of the heart

12

Right oriented EKG must be performed when

pts under the age of 2 and pts with dextrocardia (opposite oriented cardiac axis)

Telemetry monitoring can be done in __ leads

3 and 5 leads

3 lead telemetry uses

white, black and red leads

5 lead telemetry uses

white, black, red, brown, green leads

12 lead EKGs monitor (how much time frame)

10 seconds

Holter monitors monitor (how much time frame)

24 to 72 hours of continuous monitoring

When monitoring pts with the holter monitor

ask them to keep a diary of activities

2 types of Holter monitors

5 lead (2 channel) and 7 lead (3 channel)

Pt instructions for holter monitoring

keep the monitor dry, maintain a log of activities, use event button to note when they experiene symptoms, avoid strong EMF fields

EKG is a graph of

voltage over time

Standard paper feed speed

25mm/seconds

Standard gain (voltage) setting

10mm/mV

1500 method

1500/number of small boxes in the R to R interval

Size of one small box

1 mm

Size of one large box

5 mm

Sequence method

300/ number of large boxes

6 second method

count the number of QRS sequences in two of the section (3 second marks are denoted by tick marks at the top of the page) and then multiply that by 10

Method best for tachycardia or when needing precise measurements

1500 method

Normal sinus rhythm

(picture)

Sinus bradycardia

(picture)

Sinus tachycardia

(picture)

Atrial fibrillation

(picture)

Atrial flutter

(picture)

Depression of J point and ST segment indicate

myocardial infarction (MI)

Pt related artifacts on EKG

seizure, trembling, fast breathing, dry or wet skin, lotion on skin

Non patient related artifacts on EKG

expired or damaged electrodes, damaged lead cables, cell phone interference, EMF

Seziore on EKG

jagged tracing, uneven peaks

Trembling on EKG

jagged interruptions in regular tracing

Dry or wet skin/ gel problems on EKG

loose lead warning on machine, unexplained flatline

Cell phone or other electrical interference on EKG

flutter or repeating P waves

ICS

intercostal space

WTC

wilson’s central terminal

NSR

normal sinus rhythm

Heart block

a result of damage to the his purkinje system, represents a dealy or failure between the pacers of the atrium and the ventricles and shows up as abnormalities in the PR interval and a possibly wider QRS complex

Morphology

the study of the form or shape of an EKG tracing

Sinus rhythm

a rhythm set by the SA node

Telemetry

the process of recording and transmitting the readings of an instrument

Precordium

the portion of the body that is the anterior chest wall over the heart