THE CARDIOVASCULAR
SYSTEM
THE HEART AS A PUMP
WHAT MAMMAL HAS THE
LARGEST HEART?
WHAT MAMMAL HAS THE LARGEST
HEART?
 The Blue Whale
 It’s aorta is large enough that an adult can
crawl through it.
 It pumps approximately 15,000 pints of blood
compared to 8 pints in a human being.
WHICH MAMMAL HAS THE
NEXT LARGEST HEART,
SECOND TO THE BLUE
WHALE?
WHICH MAMMAL HAS THE NEXT
LARGEST HEART, SECOND TO THE
BLUE WHALE?
WHY?
HOW BIG IS THE HUMAN
HEART?
 Adults: the size of two fists
 Pediatrics: the size of a fist
THE HEART BEATS
APROX. 100,000 TIMES
A DAY
 In an average lifetime the heart will beat 2.5
Billion times!
THE HEART PUMPS ABOUT 1
MILLION BARRELS OF BLOOD
DURING AN AVERAGE LIFETIME
 That is enough to fill 3 supertankers
A KITCHEN FAUCET WOULD NEED
TO BE TURNED ON FULL BLAST
FOR 45 YEARS TO EQUAL THE
AMOUNT OF BLOOD PUMPED BY
THE HEART IN A LIFETIME.
THE HEART PUMPS BLOOD TO
ALMOST ALL OF THE 75
TRILLION CELLS IN THE BODY.
THE ONLY CELLS WITH NO BLOOD
SUPPLY ARE THE CORNEAS.
THE LUB-DUB SOUND MADE BY
THE HEART IS SOUND MADE BY
THE 4 VALVES WHEN THEY
CLOSE.
THE HEART DOES MORE WORK
THAN ANY OTHER MUSCLE IN THE
BODY.
THE HEART BEGINS BEATING 4
WEEKS AFTER CONCEPTION.
A WOMAN’S HEART BEATS FASTER
THAN THAT OF A MAN’S.
 The average heart rate for a man is 70 while it
is 78 for a woman.
WHEN THE BODY IS AT
REST:
 IT TAKES ONLY 6 SECONDS FOR
THE BLOOD TO TRAVEL FROM
THE HEART TO THE LUNGS AND
BACK
 8 SECONDS TO TRAVEL TO THE
BRAIN AND BACK
 16 SECONDS TO TRAVEL TO THE
TOES AND BAC K
THE PULMONARY ARTERIES ARE
THE ONLY ARTERIES TO CARRY
UNOXYGENTATED BLOOD AND THE
PULMONARY VEINS ARE THE ONLY
VEINS TO CARRY OXYGENATED
BLOOD.
VIDEOS
 https://www.youtube.com/watch?v=7XaftdE_
h60
 https://www.youtube.com/watch?v=K57qjYYj
gIY
Label The Following Structures

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Superior Vena Cava
Inferior Vena Cava
Pulmonary Artery
Pulmonary Vein
Aorta
R Atrium
L Atrium
R Ventricle
L Ventricle
Tricuspid Valve
Mitral Valve
Pulmonic Valve
Aortic Valve
Write Oxygenated Blood on the side w/Oxygenated Blood and
Unoxygenated blood on the side w/Unoxigenated blood.
Heart Valves
Memory Tip
 Tricuspid Valve is on the Right side of the
Heart by noting the letters R and T are close
together in the alphabet.
 Mitral Valve is on the Left side of the Heart ,
so remember L and M are side by side in the
alphabet.
Tricuspid Valve
 The valve between the R atrium and R
ventricle.
Pulmonic Valve
 The valve between the r ventricle and the
pulmonary arteries.
Mitral Valve
 The valve between the L atrium and L
ventricle.
Aortic Valve
 The valve between the L ventricle and the
Aorta.
Stenosis of the Valve
 Stenosis is the term for a valve that doesn’t open
properly. The flaps of a valve thicken, stiffen, or
fuse together. As a result, the valve cannot fully
open. Thus, the heart has to work harder to
pump blood through the valve, and the body
may suffer from a reduced supply of oxygen.
 http://www.heart.org/HEARTORG/Conditions/M
ore/HeartValveProblemsandDisease/ProblemHeart-Valve-Stenosis_UCM_450369_Article.jsp
Valve Regurgitation
 Regurgitation is the name for leaking heart
valves. Sometimes the condition is minor and
may not require treatment, but other times valve
regurgitation places a strain on the heart. It can
cause the heart to work harder to pump the
same amount of blood.
 http://www.heart.org/HEARTORG/Conditions/M
ore/HeartValveProblemsandDisease/ProblemHeart-ValveRegurgitation_UCM_450736_Article.jsp
Heart Murmur
 The sound made by a valve that is not
functioning properly.
Types of Valve Replacements:
Mechanical Valve
Donor Valve
Valve Replacement Surgery
THE ELECTRICAL COMPONENT
OF THE HEART
Physiology of Cardiac Conduction
 In an adult with a healthy heart, the heart
rate is usually about 72 beats per minute.
 The excitatory and electrical conduction
system of the heart is responsible for the
contraction and relaxation of the heart
muscle.
Sinoatrial Node (SA Node)
 Pacemaker of the heart
 This node is located along the posterior wall
of the right atrium right beneath the opening
of the superior vena cava.
 It is crescent shaped and about 3 mm wide
and 1 cm long.
Atrioventricular Node (AV Node)
 The impulse travels from the SA node through
the internodal pathways to the atrioventricular
node (AV node).
 The AV node is responsible for conduction of
the impulse from the atria to the ventricles.
 The impulse is delayed slightly at this point to
allow complete emptying of the atria before
the ventricles contract.
 The impulse continues through the AV bundle
and down the left and right bundle branches
of the Purkinje fibers.
 The Purkinje fibers conduct the impulse to all
parts of the ventricles, causing contraction
(Guyton, 1982).
ECG or EKG
 Electrocardiogram
 A recording of the electrical activity of the
heart.
 An ECG is a piece of graph paper containing a
record of the electrical events in the heart.
EKG
 A 12 lead EKG shows 12 different views of the
electrical activity of the heart
Abnormal heart rhythms occur for
several reasons.
 The vagal stimulation of the parasympathetic nervous system
can cause a decrease in the rate at the SA node and can also
decrease the excitability of the AV junction fibers. This causes
a slowing of the heart rate, and in severe cases a complete
blockage of the impulse through the AV junction.
 Sympathetic stimulation also effects cardiac rhythm and
conduction. It increases the rate at the SA node and increases
the rate of conduction and excitability throughout the heart. It
also increases the force of myocardial contraction.
Subsequently, the overall workload on the heart is increased.
 A small area of the heart can become more excitable than
normal, which causes abnormal heart beats called ectopy.
Ectopic foci are usually caused by an irritable area in the heart.
This irritability can be caused by ischemia, stimulants such as
nicotine and caffeine, lack of sleep or anxiety (Guyton, 1982).
Parasympathetic stimulation
of the heart can:
 A. Increase the heart rate
 B. Increase contractility of the heart
 C. Decrease the heart rate
Cardiac Arrhythmias
 The heart usually follows a sequence of
events at regular intervals.
 Normally the rhythm is regular and the rate is
between 60-100 beats per minute.
 Sometimes irregular beats occur, these are
called arrhythmias.
Cardiac Arrhythmias
 Arrhythmias usually originate in the atria or
AV node and aren’t a problem
 Those that originate in the ventricles are
more dangerous and can be life threatening
because they affect blood flow.
Lead Placement (5 lead)
 Where?
 What color lead?
 Right Arm- White
 Left Arm- Black
 Chest- Brown
 Right lower-Green
 Left lower- Red
Lead Placement (5 lead)
 Remember
 Smoke over Fire
 Clouds over Grass
 White on Right
Lead Placement (12 Lead)
Systematic Interpretation
 Is the rhythm regular or irregular?
 Regularity between an R to the next R-wave
 What is the ventricular rate? Rate
 Is there a P wave for every QRS? P:R ratio
 What is the measurement from the beginning of
the P wave to the beginning of the QRS
complex? P-R Interval
 What is the measurement from the beginning of
the Q-wave to the end of the S-wave?
 QRS duration
 What is the interpretation of the rhythm?
 Interpretation
Measurement of Regularity
Regular or Irregular?
Regular or Irregular?
Regular or Irregular?
Counting a 6 second strip
 There are a few ways to count ECGs
 Determine that you have a 6 second strip
 Count the number of R Waves
 Multiply by 10
 You have your heart rate!
Rate?
Rate?
Rate?
How to Read an EKG Strip
 EKG paper is a grid where Time is measured
along the horizontal axis.
 Each small square is 1 mm in length and
represents 0.04 seconds.
 Each larger square is 5 mm in length and
represents 0.2 seconds.
How to Read an EKG Strip
 Voltage is measured along the vertical axis.
 10 mm is equal to 1mV in voltage.
How to Count Squares…
 A few simple guidelines:
 Each small square on the EKG graph is .04 seconds
 If the count begins or ends at the middle of a
square add .02 seconds.
 WATCH YOUR DECIMAL POINTS!
 Normal EKG tracings consist of waveform
components that indicate electrical events
during one heart beat. These waveforms are
labeled P, Q, R, S, T and U. The following
descriptions are with respect to Lead II.
 P wave is the first deflection and is normally a
positive (upward) waveform. It indicates atrial
depolarization (when the atrial contraction
occurs).
 QRS complex follows the P wave. It normally
begins with a downward deflection, Q; a
larger upward deflection, R; and then a
downward S wave. The QRS complex
represents ventricular depolarization and
contraction.
 T wave is normally a modest upward
waveform, representing ventricular
repolarization.
 U wave indicates the recovery of the Purkinje
conduction fibers. This wave component may
not be observable
PR Interval
The measurement from the beginning of the
P wave to the beginning of the R wave.
How to Read an EKG Strip
 EKG paper is a grid where Time is measured
along the horizontal axis.
 Each small square is 1 mm in length and
represents 0.04 seconds.
 Each larger square is 5 mm in length and
represents 0.2 seconds.
How to calculate the PRN
interval
 To measure the PR interval, count the number of
small squares between the start of the p wave to
the start of the QRS complex; then multiply the
number of squares by 0.04 seconds.
 Normal PR Interval= 0.12-.20 seconds
 Also evaluate if PR Intervals are constant or
varying across the EKG strip. If they vary,
determine if the variations are a steady
lengthening until the point where an expected
QRS does not appear.
PR Interval questions to
address:
 ◦Does the PR-Interval fall within the norm of 0.12-
0.20 seconds?
 ◦Is the PR-Interval constant across the ECG
tracing?
YOUR TURN
 On the samples in your packet measure the
P-R interval of the strips.
 Once you’ve completed those go to the
following website and complete the practice
quiz.
http://www.practicalclinicalskills.com/ekglesson-PRInterval-Quiz.aspx?courseid=301
QRS Interval
 The QRS complex indicates ventricular
depolarization. Depolarization triggers
contraction of the ventricles.
 Because of the larger tissue mass, the QRS
complex is larger than the P wave
QRS Interval
 In this step, measure the QRS interval from
the end of the PR interval to the end of the S
wave. Use calipers, marking paper or by
counting small boxes.
 Normally this interval is 0.06 to 0.12 seconds
(1.5 to 3 boxes).
QRS Questions:
 ◦Does the QRS interval fall within the range
of 0.08-0.12 seconds?
 ◦Are the QRS complexes similar in
appearance across the ECG tracing?
Your Turn
 On the samples in your packet measure the
P-R interval of the strips.
 Once you’ve completed those go to the
following website and complete the practice
quiz.
 http://www.practicalclinicalskills.com/ekglesson-QRSInterval-Quiz.aspx?courseid=301
T Wave
 The T wave indicates the repolarization of the
ventricles.
 It is a slightly asymmetrical waveform that
follows (after a pause), the QRS complex.
 Take note of T waves that have a downward
(negative) deflection or of T waves with tall,
pointed peaks.
Sinus Rhythms
 The dysrhythmias in this category occur as a result of influences
on the Sinoatrial (SA) node.
 Rhythms in this category will share similarities in a normal
appearing P wave, the PR interval will measure in the “normal
range” of 0.12 – 0.20 second, and the QRS typically will measure
in the “normal range” of 0.06 – 0.10 second.
 For the most part, dysrhythmias in this category either effect the
rate, rhythm regularity or both within a particular tracing. We will
be discussing the following complexes and rhythms:
◦Normal Sinus Rhythm
◦Sinus Bradycardia
◦Sinus Tachycardia
◦Sinus Dysrhythmia (Arrhythmia)
◦Sinus Arrest
◦Sinus Exit Block
Normal Sinus Rhythm
 ◦Also known as Sinus Rhythm is the only rhythm
when each of the five steps of rhythm analysis are
“normal”.
 This rhythm will be regular, in a heart rate range
between 60 – 100 bpm,
 P waves are upright and uniform in appearance (in
Lead II),
 a P wave for each QRS complex
 the PR interval will measure in the normal range of
0.12 – 0.20 second (and measure the same each
time),
 the QRS complex morphology will be similar beatto-beat and measure between 0.06 – 0.10 second
(and measure the same each time).
Sinus Bradycardia
 Everything will be normal like in Sinus
Rhythm except the rate will be less than 60
bpm.
Sinus Tachycardia
 The only difference between Normal Sinus
Rhythm and Sinus Tachycardia is the rate
exceeds 100 bpm. All other steps of rhythm
analysis will be “normal.
 ◦An additional challenge that will present as
rhythm rates accelerate is that the cardiac
complexes will come closer together. This can
result in the P wave becoming partially or
completely buried within the T wave of the
previous cardiac complex.
Sinus Arrhythmia
 Sinus Dysrhythmia closely resembles Normal
Sinus Rhythm with the only distinction being
the intervals from one cardiac complex to the
next are changing as influenced by the
patients respiratory pattern.
 Note the changing R to R Intervals.
 PAC- Premature Atrial Contraction
Sinus Arrest (Pause)
 Sinus Arrest occurs when there is a sudden
absence of electrical activity initiated by the
SA node. This results in a pause in the
electrical activity seen on the tracing.
Remember, no electrical activity = no
depolarization and contraction.
 A pause of six-seconds is considered a
medical emergency and emergency
procedures must be initiated!!
Sinus Arrest (Pause)
 It is important to measure the duration of the pause
and report this information along with the
frequency of the pauses if there are more than one.
 ◦The pause is measured by placing your caliper tips
on the last R wave just prior to the pause and the R
wave immediately following the pause. Count the
number of small boxes and multiply by 0.04
second. This will be reported as part of the
interpretation.
Atrial Flutter
 Atrial Flutter occurs when there is an obstruction within
the atrial electrical conduction system.
 Due to this impediment a series of rapid
depolarizations occur.
 These depolarizations may occur two, three, four or
more times per QRS complex.
 The AV node functions like a “gate keeper” blocking the
extra impulses until the ventricular conduction system
is able to accept the impulse.
 The impulse that is accepted will cause the QRS
complex to occur.
Atrial Flutter
 Each flutter wave represents atrial
depolarization. This will be noted next to the P
wave step in rhythm analysis. There is no PR
interval measurement.
 When the tracing is interpreted, the ratio of P
waves to each QRS complex will be documented
along with the rhythm i.e. Atrial Flutter 4:1
(indicates 4 “P” waves to each QRS complex). Not
all Atrial Flutter will have a regular rhythm. In that
case just document and report your observations.
Atrial Fibrillation
 Not all fibrillatory waves are created equal. The
“P" waves can be coarse (majority measure 3 mm
or more) or can be fine (majority of waveforms
measure less than 3 mm) to almost absent.
 Regardless always report your observations.
 Many times when a patient has "new onset" Atrial
Fibrillation the patient will report with a heart rate
of 160 bpm or more.
Atrial Fibrillation
 When a patient experiences A-fib, the atria are not
contracting as they normally would. They are just
quivering. This absence of contraction of the atria can
result in a loss of cardiac output anywhere from 15 - 30%
due to the absence of "atrial kick". This is why the heart
rate is so high. The body is trying to maintain
homeostasis.
 It will be impossible to determine the atrial rate. You will
only be able to analyze and report the ventricular rate.
 Atrial Fibrillation with a ventricular response in excess of
100 bpm is commonly referred to as Atrial Fibrillation with
“rapid ventricular response” or "uncontrolled A-fib".
A Flutter VS A Fib
Ventricular Rhythms
 Rhythms are often named according to the origin
of the electrical activity in the heart or the
structure where the problem is occurring.
 Ventricular Rhythms are aptly named due to the
area of stimulation occurs in the ventricles.
 Dysrhythmias in this category occur as a result of
either a failure of the higher (faster) pacemakers
within the heart or an abnormal locus of
stimulation within the ventricles is occurring at a
faster rate than the other pacemaker sites and
thus takes over as the pacemaker of the heart.
 Remember, the fastest electricity in the heart
(regardless of location) will dictate the heart rate.
Ventricular Rhythms
 Each rhythm in this category will share unique
morphologic features which separate them from
other rhythms.
 Other than Asystole and Ventricular Fibrillation
which are unique even within this category, the
remaining ventricular rhythms typically present
without P waves and will display a wide, bizarre QRS
complex (measuring 0.12 seconds or greater).
 After learning the unique features just described, it is
simply a matter of recalling the heart rate range
associated with the dysrhythmia.
Important Terminology
 Unifocal – abnormal complexes are of the same
shape
 Multifocal – abnormal complexes are of two or
more different shapes. This indicates the
impulse causing the PVC’s are coming from
different locations.
Important Terminology
 Bigeminy – abnormal complexes occur every
second complex
 Trigeminy– abnormal complexes occur every third
complex
Important Terminology
 Couplet – Two PVC’s together
 Run of Ventricular Tachycardia (V Tach) – Three or
more PVC’s in a row at a rate of 100 bpm or
greater. Also known as Triplet PVC’s or Salvo
PVC’s
Premature Ventricular
Contraction (PVC)
 PVC’s may occur for a number of different reasons i.e., diet,
fatigue, stress, disease, ischemia to name a few.
 PVC’s occur when an early electrical impulse occurs from a
location in either ventricle
 The locus of stimulation being different, results in a change in the
morphology of the cardiac complex.
 Note the absence of P wave and the wide, bizarre QRS complex.
 PVC’s can occur occasionally or frequently.
 PVC’s can be observed with or without a pattern
PVC
Agonal Rhythm
 This is a life-threatening dysrhythmia. Agonal rhythm is often the
last ordered semblance of organized electrical activity in the heart
prior to death.
 Heart rate is less than 20 bpm, without P waves and a wide,
bizarre QRS complex.
 The rate is often so slow, that on a singular six-second rhythm
strip it will be impossible to determine whether the rhythm is
regular or irregular. There must be at lest three complexes on the
tracing to make this call. Many times there will only be one or two
complexes captured on the tracing. This is a MEDICAL
EMERGENCY
Ventricular Tachycardia
 The morphologic features continue with the
dysrhythmia. No P wave, wide and bizarre QRS.
 Ventricular Tachycardia occurs when the rate exceeds
100 bpm.
 This rhythm must always be reported whether the
patient appears stable or not.
 Depending upon their level of consciousness and
blood pressure. The patient may be treated with
medications, synchronized cardioversion or in the
worst case scenario a defibrillator and BLS/ACLS
response.
Ventricular Fibrillation
 The morphologic features are different with this
dysrhythmia. No P wave and no QRS complexes.
This rhythm presents with a chaotic waveform
which reflects the electrical chaos occurring within
the heart.
 The heart is not actually beating as we know it. The
chaos occurs as a result of small regions of tissue
which are independently depolarizing.
Ventricular Fibrillation
 Fibrillatory waves may be coarse or very fine. This is
based upon their size. The longer V Fib occurs, the
smaller the waveforms are likely to be.
 Coarse V Fib is when a majority of the waveforms
measure 3 mm or greater
 Fine V Fib is when a majority of the waveforms
measure less than 3 mm
 This is absolutely a life-threatening dysrhythmia
which requires, immediate, effective, and aggressive
care.
 If your patient is talking to you when you see this on
the monitor, then your patient is not in V Fib. Always,
check your patient first, but there will likely be a loose
or disconnected lead wire or electrode.
Ventricular Fibrillation
Asystole
 This dysrhythmia occurs when there is a total





absence of electrical activity in the heart.
The patient is clinically dead.
Sometimes this tracing is referred to as straight
line or flat line.
There will be an absence of P waves and QRS
complexes.
True Asystole is an absolute medical
emergency!
If your patient is speaking to you, they are NOT in
Asystole. Check your attachments and
equipment.
Asystole
Pulseless Electrical Activity
PEA
 In PEA the heart muscle looses its ability to
contract even though electrical activity is present.
 On an ECG you will see evidence of organized
electrical activity but you won’t be able to palpate
a pulse or measure the blood pressure.
 Treat as Asystole!
Heart Blocks
 In people with heart block the electrical pulses
that control the heart rate are disrupted,
causing the heart to beat more slowly.
 It's a type of arrhythmia, which is a medical term
used to describe problems with the rate or rhythm
of the heartbeat.
 There are three levels of heart block, and usually
only the most serious type causes symptoms
Types of heart block
 There are three main types of heart block:
• first-degree heart block
• second-degree heart block
• third-degree heart block
First Degree Block
 In first-degree heart block, there's a split-second
delay in the time it takes electrical pulses to move
through the AV node. First-degree heart block
rarely causes any noticeable symptoms.
 Will look like Sinus Rhythm with one exception:
 The P-R interval will be constant throughout the tracing
and measure greater than 0.20 seconds
Second Degree Heart Block
 In second-degree heart block there's a series of
increasing delays in the time it takes the AV node
to send the pulse to the ventricle. This will
eventually lead to a heartbeat being skipped.
 There are two sub-types of second-degree heart
block.
Second Degree Type I
Wenckebach
 This is the less serious type. It occasionally causes
mild dizziness and doesn't usually require
treatment.
 The unique feature (hallmark) of this dysrhythmia is
the presence of a prolonging P-R interval from one
cardiac complex to the next, until it reaches a point
where the QRS complex is non-conducted ( blocked
or more simply missing). Then the pattern starts
over again.
Second Degree Type I
Wenckebach
 P-R Interval gets wider and wider and then
drops the QRS.
https://www.youtube.com/watch?feature=player_embedded&v=hO_ny2_
2N8o
Second Degree Type II
Mobitz Type II
• The hallmark of this dysrhythmia is a constant P-R
interval with missing QRS complexes.
• This dysrhythmia may present in a couple of
different ways.
• A. QRS complexes occurring in a specific pattern in a
ratio with the P waves. This is often referred to as 2:1 or
3:1 block depending upon the ratio of P waves to each
QRS complex.
• B. QRS complexes occur in a more unstable,
unpredictable manner.
Second Degree Type II
Mobitz Type II
 Either presentation requires immediate
reporting due to its potential for conversion to
Third Degree (Complete) Heart Block.
Third Degree Heart Block
Complete Heart Block
 In third-degree or complete heart block there's no
transmission of electrical pulses between the atria
and the ventricles through the AV node.
• The outcome of this impediment are two
independently functioning pacemakers within the
heart (typically one is supraventricular, the other is
ventricular).
• Essentially, the atria and ventricles are electrically
separated (dissociated) from one another.
 What will be seen are regularly occurring P
waves and QRS complexes, but at two distinctly
different rates.
 Complete heart block presents with Regular P to
P and R to R intervals and a variable P-R interval.
What is this Rhythm?
What is this Rhythm?
What is this Rhythm?
ST Elevation
STEMI
STEMI
Medical Emergency!! Pt NEEDS
the CATH LAB STAT.