Download The HEART

The HEART
Medical Therapeutics
Introduction
• Triangular shape
• Size of your fist
• Located between the lungs in lower
portion of mediastinum behind sternum
• Blunt end is called apex and points toward
left
• Site where heart sounds are best heard
Heart Chambers
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Organ is hollow
Divided into right and left sides
Septum divides
Contains four hollow chambers
– Atria- top chambers or receiving chambers
– Ventricles-lower chambers or discharging
chambers
• Atria are smaller than ventricle
• Have right and left atria as well as right and
left ventricles
Chambers of the Heart
Layers of Heart
• Endocardium- inner most layer of thin
smooth tissue
• Myocardium-middle muscular layer
• Pericardium-outer layer that consist of two
layers of fibrous tissue
– Visceral Pericardium or epicardium- inner layer
of pericardium produces pericardial fluid
– Parietal Pericardium- loose fitting covering on
the outside of the heart
• Epi-upon or on
Endo-within or in
Heart Action
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Heart is a muscular pumping device
Systole- contraction of the heart
Diastole relaxation of the heart
When heart beats→atria contract first
(atria systole)→forcing blood into
ventricles
• Once filled→two ventricles contract
(ventricular systole)→blood forced out of
heart
Blood Flow Right Side
• Enters heart through Superior/Inferior
Vena Cava
– Blood is oxygen poor from the body
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Goes to Right Atrium
Through Tricuspid Valve
Into Right Ventricle
Through Pulmonary Valve
To Pulmonary Artery and into lungs
Blood Flow Left Side
• From lungs where O2 is added and CO2
removed goes to
• Pulmonary Veins O2 rich and then into
• Left Atrium then through
• Mitral Valve to the
• Left Ventricle then through
• Aortic Valve to the
• Aorta where it is carried to all parts of the
body
Anatomy of Heart
Heart Valves
• Atrioventricular Valves-separate the atria
from the ventricles
– Triscupid valve- between right atrium and
ventricle
– Bicuspid or Mitral valve-between left atrium and
ventricle
– Prevents backflow of blood into the atria when
the ventricles contract
– Chordae tendineae-attaches AV valves to the
wall of the heart
Atrioventricular Valves
Heart Valves
• Semilunar Valves-located between the two
ventricular chambers and large arteries that
carry blood away from the heart
– Pulmonary semilunar valve- located between
right ventricle and pulmonary artery
– Aortic semilunar valve- located between left
ventricle and aorta
– Both valves prevent backflow of blood into
ventricles
Semilunar Valves
Disorders of Valves
• Incompetent valves-allow some blood to flow
back into the chamber from which it came
• Stenosed Valves- valves that are narrower
than normal, slowing blood flow from a heart
chamber
• Mitral Valve Prolapse- (MVP) when the flaps
of the Mitral valve extend back into the left
atrium, causing incompetent valves
• transesophageal Echocardiogram
• Transesophageal Echocardiogram
anatomy
Diseases of Layers
• Endocarditis-inflammation or infection of
inner layer of heart
• Myocarditis-infection or inflammation of
myocardium
• Pericarditis-inflammation or infection of
pericardium
Diseases
• Thrombosis- blood clot
– Caused by endocardial lining becoming rough
and abrasive to RBC’s passing over its
surface.
– As blood flows over a rough surface clots are
subject to form
• Embolis-blood clot that is flowing in blood
stream
Diseases of Layers
• Pericardial Effusion-when pericardial fluid,
pus or blood may accumulate in the space
between two pericardial layers and impairs
the pumping action of the heart
• Cardiac Tamponade- when pericardial
effusion gets worse and develops a serious
compression of the heart
Heart Sounds
• Listen with stethoscope on anterior wall of
chest ( auscultate )
• Rhythmic and repetitive sounds “Lub dub”
• First sound or lub-caused by vibration and
abrupt closure of AV valves as ventricles
contract
• Longer sound with a lower pitch
• Second sound or dub-caused by closure
of semilunar valves during diastole
Heart Sounds
• Heart Murmurs-abnormal heart sounds caused
by disorders of valves
• Incompetent valves cause a swishing noise as a
“lub” or Dub” ends
• Stenosed valves, often cause swishing sounds
just before “lub” or “dub”
Coronary Circulation
• Heart muscle or myocardium requires on
going supply of blood to function
• Coronary circulation-the delivery of oxygen
and nutrient rich arterial blood to the cardiac
muscle and removal of oxygen-poor blood
from the active tissue to the venous system
• Blood flows into the heart muscle by way of
two small vessels called Right Coronary
Artery and Left Coronary Artery
Coronary Circulation
Coronary arteries are the first branches of the
aorta
• Myocardial Infarction or heart attack occurs
when one of these arteries are occluded
with a blood clot or plaque
– Tissue death occurs when area is deprived of
oxygen ( ischemia )
– Symptoms – pain, nausea, irreg. pulse, cold
and clammy, anxiety, SOB
– Reduce activity, NTG
Coronary Circulation
Blood Flow Through the Heart
• Superior & inferior vena cava
• Right atrium
• Tricuspid valve
• Right ventricle
• Pulmonary semilunar valve
• Pulmonary arteries
• Lungs to exchange gases
• Pulmonary veins
• Left atrium
• Bicuspid / Mitral valve
• Left ventricle
• Aortic semilunar valve
• Aorta all parts of the body
• Arteries
• Arterioles
• Capillaries
• Venules
Conduction System
• How does the heart
know when to pump?
• What makes the atria
contract before
ventricles?
• How do we evaluate
the conduction
system?
Conduction System
Upon completion of this lesson
students will be able to give purpose
and importance of the heart
conduction system and identify
placement of EKG leads.
Conduction System
• The heart is a large muscle
that acts as a pump, but it has
to have an impulse from the
brain and electrical stimulation
to tell it how fast and when to
beat.
Conduction
• Special tissues in the heart
transmit electrical impulses.
• These impulses cause the
heart to contract and relax.
• electrical system of heart
Conduction System
• Cardiac muscles are
coordinated by electrical
impulses
• Heart has own built in
conduction system that is
embedded into wall of the heart
to generate and conduct
impulses
Sinoatrial node (SA) node
• pacemaker of the heart. This is
where transmission begins and
sets the rhythm of the heart.
Normal pulse rate is 60 to 100
beats per minute.
• The SA node is located high on
the right atrium close to where the
superior vena cava enters the
right atrium.
Internodal Pathway
• Located in the walls of the atria.
• Links the SA node to the AV node
• It takes about 0.03 seconds for
the impulse to travel from the SA
to AV node.
Atrioventricular node (AV node)-
• AV node is located on the
interatrial septum close to the
tricuspid valve.
•Pulse rate here about 40 to 60
beats per minute.
• Bundle of HIS- AV Bundle (
Bundle Branches)
•The only electrical connection
between the atria and the ventricles
• emerges from the AV node to begin
the conduction of the impulse from
the AV node to the ventricles.
• Pulse rate is about 30 to 40 beats per
minute.
Bundle Branches- Right
and Left
R Bundle- R Ventricle
L Bundle- L Ventricle
• Purkinje Fibers distribute the
impulse to the ventricular
muscle.
• The rate here is also about
30 to 40 beats per minute or
less.
Conduction pattern
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Sinoatrial (SA) node
Internodal Pathways
Atrioventricular (AV) node
Bundle of HIS -AV
R & L Bundle Branches
Purkinje Fibers
Conduction System
• Depolarization- initiates
chain that results in
contraction of the heart
• Repolarization- Period of
Electrical Recovery
Electrical complex- (PQRST)
Interpreting EKG video
P wave represents the
Atria contracting
sinoatrial (SA) node.
• QRS complex
represents the
contraction of the
ventricle
• T wave
Repolarization of
Ventricles
• Go to skills Lab
• PR intervaltime for
impulse to
travel from
SA node to
AV node
• Q-T intervaltime for
ventricles to
contract,
recover, and
repolarize
• S-T segmenttime between
contraction of
ventricles and
recovery.
Cardiac Leads
• On a routine EKG
there are 10 lead
positions
• Chest wall 6
locations
• Left arm
• Right arm
• Left leg
• Right leg
•Each lead
indicates the walls
of the heart. There
is front, back, and
sides.
•Abnormal findings
can indicate
problems.
• This is how the
location of an MI
(heart attack) is
determined.
•ECG placement
Conduction System
Normal Electrocardiograph
Conduction System
• Electrodes- electrical impulse sensors
that transmit information from body to
machine that produce an electrical
tracing.
Cardiac Arrhythmia
• Bradycardia- slow heart rate, most often
caused by defective SA node
• Tachycardia-fast heart rate, improper
autonomic control of the heart
• Sinus arrhythmia-variation of heart rate
during breathing cycle
– Heart rate increases with inspiration and
decreases with expiration
Cardiac Arrhythmia
• Fibrillation-a condition in which cardiac
muscle fibers contract out of step with each
other
– Atrial Fibrillation-common in elderly, can be
treated with medications or defribrillation called
cardioversion or even ablation – atria quivering
– Ventricular Fibrillation- life-threatening condition
in which defribillation is a must (shocking with
defibrilator) – ventricles are quivering
Cardiac Arrhythmia
How to perform an EKG
•Arrhythmia abnormal heart rhythm
•Ventricular Fibrillation
Cardiac Arrhythmia
• Premature Contractions- contractions that
occur before the next expected contraction
in a series of cardiac cycles
Cardiac Arrhytmias
Coronary Diseases
• Atherosclerosis- “hardening of the arteries”
due to a build up of lipids or other
substances inside walls of blood vessels
• Causes Hypertension, diabetes,
overweight,heredity, smoking, lack of
exercise, diet high in cholesterol
• Coronary Artery Disease - Khan
Coronary Diseases
• Angina Pectoris-Severe chest pain due
that occurs when the myocardium is
deprived of oxygen
– Usually a warning sign that the arteries are no
longer able to supply enough blood and
Oxygen to the heart muscle
– Treat with Nitroglycerin
Coronary Circulation Treatment
• Coronary Artery Bypass Graft-Surgery to
bypass a damaged or occluded coronary
artery
Heart Failure
• Inability to pump enough returned blood to
sustain life
• Right-sided heart failure-failure of the right
side of the heart to pump blood, usually
because the left side is not pumping
effectively
• Left-Sided heart failure- Congestive Heart
Failure-inability of left ventricle to pump
effectively
Congestive Heart Failure
Heart enlarges due to poor blood flow
(hypertrophy)
• Symptoms – Hemoptysis, cough, dyspnea,
orthopnea, ascites, neck vein
distention,fatigue, hypoxia, confusion,
edema, cyanosis
• Treatments – Lasix, low sodium
diet,restrict fluids, daily wt.
Vessels
• Arteries – Muscular, O2 rich, carry blood
away from the heart
Vein
• Veins – Valves, Co2 rich, carry blood
toward the heart
• Capillaries – walls 1 cell thick, gas
and nutrient exchange takes place
Peripheral Vascular Disease
• Vessels in extremities damaged
• Symptoms – burn during exercise, hair
loss on feet and legs, thick toenails, red or
brown skin, dry,scaly or shiny skin,
edema,
Blood
• Plasma – liquid, clear yellow, 55% blood
• Erythrocyte – RBC, Have a protein called
hemoglobin that carries O2
• Lymphocyte – WBC fights infection
• Thrombocyte – Platelet, blood clotting
• Kahn Blood testing
Anemia
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Pernicious anemia – lack of B12
Sickle cell – hereditary
Iron Def. – diet, loss of blood
Symptoms- no energy, pale, dyspnea,
rapid pulse, cold, dizzy,tachypnea