Heart Failure

Your heart as pumping has resposibillity to provide oxygenated blood to around cells including the heart itself and return deoxygenated blood to the heart, where it travels to the lungs to be reoxygenated. First of all, deoxygenated blood comes from the body, from the venous system, and travels via the inferior or from lower body and superior or from upper body and coming to vena cava to the right atrium.

Blood flows from the right atrium to the right ventricle and out to the lungs through the pulmonary artery. The blood then picks up oxygen in the lungs and travels via the pulmonary vein to the left atrium and down to the left ventricle. From the left ventricle, oxygenated blood is pumped out through the aorta to the body.

The entire heart acts as a pump and likes to move blood in one direction: forward. If blood is not moving forward, it backs up into the venous or arterial system. If the right side of the pump begins to fail, blood backs up into the venous system.When the left side of the heart fails, blood backs up into the lungs, preventing blood from being pumped out to the rest of the body.


Cardiac output

Cardiac output (CO) is defined as the amount of blood ejected from the
left ventricle over one minute. The CO must remain fairly constant to
achieve adequate perfusion to around the body. Normal value for cardiac output is from
4 to 8 liters/minute.

CO is calculated using the estimation:
Heart rate (HR) _ stroke volume (SV) _ cardiac output (CO).


Stroke volume is influenced by three factors:

1. Preload is the amount of blood returning to the right side of the heart. To remember preload, think volume—you can have too much or not enough. Ways to increase preload: increase fluid volume in the vascular space, elevate the legs, and place the client in the Trendelenberg
position.Ways to decrease preload are to sit the client up with the legs down and decrease vascular volume.

2. Afterload is the pressure in the aorta and peripheral arteries that the left ventricle has to work against to get blood out. This pressure is referred to as resistance—how much resistance the ventricle has to overcome to pump blood out to the body.

The aorta is naturally a high-pressure vessel, but we don’t want it to go too high.Ways to increase afterload include making the client’s BP go up. Now the client’s left ventricle will have even more pressure to pump against. As a result, less blood will be pumped out of the heart, and cardiac output will go down. This is not nice! Ways to decrease afterload are to give your client a vasodilator or an antihypertensive. This will decrease the pressure in the aorta and therefore the heart will not have as much pressure to pump against.

Then the left ventricle will say, “Thank you! Now I don’t have to work as
hard against that high pressure to get the blood out.” Then the cardiac
output will go up.

3. Contractility is the heart’s ability to “squeeze” volume out of the ventricle.





What is the heart failure?

Heart failure is a clinical syndrome in which any abnormality of cardiac function causes either a failure of the heart to pump blood at a rate commensurate with the requirement of metabolizing tissues, or a situation in which filling pressures are elevated, or frequently both conditions simultaneously. Patients with impaired cardiac-pumping function experience symptoms related to abnormal perfusion and retention of vascular fluid volume.


Predisposing causes of heart failure.

1. Hypertension
2. Diabetes mellitus
3. Dyslipidemia
4. Valvular heart disease
5. CAD
6. Myopathy
7. Rheumatic fever
8. Mediastinal radiation
9. Sleep apnea disorders
10. Exposure to cardiotoxin agents
11. Alcohol abuse
12. Smoking
13. Collagen vascular disease
14. Thyroid disorder
15. Pheochromocytoma
16. Old age
17. Metabolic syndrome
18. CAD, coronary artery disease.



Classification of Heart Failure patients:

1. Stage A : Patient with high risks for HF
2. Stage B : Asymptomatic patients with LV dysfunction
3. Well compensated Stage C : Patients with minimal symptom treated as outpatient in office
4. Early decompensated Stage C : Patient with first hospitalization because of decompensated HF
5. Recurrent decompensated Stage C : Patients with recurrent hospitalizations because of
frequent relapse of decompensated HF
6. Stable very low EF, Stage C :Patients with multiple previous hospitalizations now
followed-up at a dedicated HF clinic





Left-sided heart failure

The Congestive heart failure is classified as left-sided heart failure or rightsided
heart failure. Left-sided heart failure is happen when the left ventricle fails and cardiac
output falls. The blood backs up into the left atrium and lungs, causing
pulmonary congestion.



What cause the left heart failure ?

Coronary artery diseases
Reduces oxygen-rich blood flow to the cardiac muscle resulting in ischemia. This decreases cardiac output. As the damaged cells begin to heal, they go through neurohormonal changes called remodeling. Remodeling is a bad thing. The “scarred” or remodeled tissue is not the same as healthy heart tissue. The remodeled cells do not contract as well as healthy heart tissue, and the client is at risk for developing congestive heart failure.

Myocardial infarction
Blockage of coronary artery impedes forward blood flow, resulting in cardiac tissue ischemia. This reduces cardiac contraction and cardiac Output.

Myocarditis or endocarditis
Inflammation of heart muscle caused by bacterial, viral, or other infection. Damages heart
muscle and impairs pumping ability .

Heart valve disorders
Narrowing of heart valves causes backward flow of blood. The heart enlarges and cannot pump effectively,so decreases CO occur.

Arrhythmias
The heart beats abnormally, leading to decreased pumping ability.

Pulmonary hypertension
Damages blood vessels in the lungs, making the heart work harder to pump blood into the arteries that supply the lungs.

Pulmonary embolism
Makes pumping blood into the pulmonary arteries difficult (due to blockage).

Hyperthyroidism
Overstimulates the heart, making it pump too rapidly and not empty completely with each heartbeat (if heart beats too fast, the ventricles do not have time to fill).Hypothyroidism Low thyroid hormones make the cardiac muscle weak, decreasing its pumping ability.

Anemia
Reduction of oxygen the blood carries, so the heart must work harder to supply the same
amount of oxygen to the tissues. The heart is now working harder to pump more oxygen around the body.

Kidney failure
Strains the heart because the kidneys cannot remove the excess fluid from the bloodstream. This leads to decreased CO.




Signs and Symptoms Left Heart Failure

Crackles
Indicates pulmonary congestion. If the left side of the heart is weak and cardiac output drops, there is a decrease in forward flow. A decrease in forward flow causes backward flow right into the lungs.


Dispnea
Excess The fluid interferes with the lungs’ ability to pick up oxygen.

Nonproductive cough
Natural response to get the fluid out of the lungs to improve gas exchange.

Blood tinged, frothy sputum
Blood and fluid are accumulating in lungs. Sputum will be frothy pink due to the presence
of blood.

Restlessness HypoxiaTachycardia
The heart rate increases as a compensatory mechanism (sympathetic stimulation) in an effort
to pick up and transport more oxygen to the cells.

S3
Normally there are two heart sounds. S1 indicates the closing of the mitral and tricuspid
valves. S2 indicates closure of the aortic and pulmonic valves. Well, when the heart fails there
is an extra heart sound, called an S3 gallop. It is described as a “floppy” sort of sound caused by
extra fluid in the ventricles S3 sounds like “Ken-tuc-ky”.

S4
Atrial contraction against the noncompliant ventricle causes an extra heart sound S4 sounds
like “Tenn-ess-ee”.

Orthopnea
The client will probably have to sit up to breathe. Sitting up allows for better chest expansion and may decrease the hypoxia.

Nocturnal dyspnea
The client experiences shortness of breath at night while lying flat. Lying flat causes all the
blood that pools in the extremities to return to the heart (preload increases). This causes CHF or
pulmonary edema.

Cool, pale skin
Peripheral vasoconstriction; the heart can’t work hard enough to pump the blood to the extremities to perfuse the tissues.







Treatments:

- Goal is to decrease workload on the heart.
- Diuretics: decrease fluid volume throughout the body.
- ACE inhibitors: dilate blood vessels decreasing workload of heart.
- Angiotensin II receptor blockers: can be used in place of ACE inhibitors.
- Beta-blockers: slow the heart rate; prevent remodeling.
- Vasodilators: cause blood vessels to dilate.
- Positive inotropic drugs: makes the heart muscle contract more forcefully.
- Anticoagulants: prevent clot formation.
- Opioids: relieve anxiety and decrease the workload on the heart especially in pulmonary hypertension.
- Oxygen therapy: improves oxygenation.
- Lifestyle modification: exercise; weight loss; reduce sodium, alcohol, and fat intake; smoking cessation; stress reduction to reduce symptoms of heart failure.
- Coronary artery bypass surgery (CABS) or angioplasty: for heart failure due to coronary artery disease (CAD).
- Heart transplant: when aggressive medical treatments are not effective.




Right Side Heart Failure

Right-sided heart failure—also known as cor pulmonale—occurs when the right ventricle can not contract effectively. This causes blood to back up into the right atrium and the peripheral circulation, which causes peripheral edema and engorgement of the kidneys and other organs.



What causes The Right Heart Failure

Left-sided heart failure
Left-sided heart failure over time will lead to right-sided heart failure. In left-sided heart failure, fluid backs up into lungs. This fluid creates increased pressures in the lungs, which is abnormal. The right side of the heart eventually becomes tired from pumping against these high pulmonary pressures. Over time the patient will experience rightsided heart failure, known as cor pulmonale.

Hypertension
Heart has to pump harder to force blood into the arteries against higher pressure. The
heart’s walls thicken (hypertrophy) and stiffen. This causes the heart to pump less blood.

Age, infiltration, infections that cause cardiac wall stiffness
Heart walls can stiffen naturally with age. Infiltration of amyloid (unusual protein not normally found in the body) can infiltrate heart walls, causing them to stiffen. Infection caused by parasites in tropical countries can cause cardiac wall stiffness.

Heart valve disorders
Hinder blood flow out of the heart; heart works harder; cardiac walls thicken; diastolic dysfunction develops that leads to systolic dysfunction.

Lung disorders COPD,Pulmonary Embolism
Cause high pressure in the lungs and can lead to right-sided heart failure. Any disease
obstructive pulmonary that causes hypoxia will cause the blood pressure in the lungs to go up . . ., pulmonary hypertension.





Sign and Symptom The Right Heart Failure

Enlarged liver (hepatomegaly) and spleen (splenomegaly)
Blood backs up into the venous system and into the liver and spleen, causing engorgement.


Epigastric tenderness
Liver and spleen have a capsule around them. This capsule does not like to stretch because it is filled with nerves and it hurts when the nerves are stretched out. When the organs become swollen, epigastric discomfort and right upper quadrant (RUQ) tenderness result

Ascites
Increased pressure in the venous system causes fluid to leak out of the vascular space into the abdominal cavity. A second reason for ascites is that the liver can no longer make albumin like it used to. Normally, albumin holds fluid in the vascular space. When albumin is low, fluid leaks out of the vascular space into the peritoneal cavity. Edema Pressure in the venous system causes fluid to leak from the vascular space into the tissues.


Anorexia, fullness, nausea
Congestion of liver and intestines

Jugular venous distension (JVD)
Blood backs up from right side of the heart into the venous system. Or, blood cannot empty into the right atrium, so it backs up into the jugular veins.

Weight
Fluid retention causes an increase in weight

Nocturia
Nocturnal fluid redistribution and resorption causes urge to void at night




Treatments:
- Goal is to decrease workload on the heart.
- Diuretics: decrease fluid volume throughout the body (heart isn’t able to pump as much volume, so we need to get rid of excess volume).
- ACE inhibitors: dilate blood vessels, decreasing workload of heart.
- Angiotensin II receptor blockers: can be used in place of ACE inhibitors.
- Beta-blockers: slow the heart rate; prevent remodeling.
- Vasodilators: cause blood vessels to dilate (this decreases workload on the left ventricle as vasodilators drop the pressure in the aorta; cardiac output will improve as well).
- Positive inotropic drugs: make the heart muscle contract more forcefully, which hopefully will increase cardiac output.
- Anticoagulants: prevent clot formation.
- Opioids: relieve anxiety and workload on the heart especially with pulmonary hypertension.
- Oxygen therapy: treat oxygen deficiency.
- Lifestyle modification: exercise; weight loss; reduced sodium, alcohol, and fat intake; smoking cessation; stress reduction to reduce symptoms of heart failure.
- Heart transplant: when aggressive medical treatments are not effective.
- EKG: shows heart strain, enlargement, ischemia.
- Chest x-ray: reveals pulmonary infiltrates and an enlarged heart
- BNP level: increased.
- Echocardiogram: evaluates pumping ability of the heart and function of the valves.
- Pulmonary artery (PA) pressure monitoring: shows elevated pulmonary artery wedge pressures and increased left ventricular end-diastolic pressure in left-sided heart failure.

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Anatomy Fisiology Of The Heart

A. The Heart

In the embryo,the heart begin to beat at 4 weeks of age, even before its nerve supply has been estabilished. If a person lives to be 80 years old, your heart continues to beat an average of 100,000 time a day, every day for each of those 80 years. Imagine trying to squeeze a tennis ball 70 times a minute. After few minutes your arm muscles would begin to tire, then imagine increasing your squeezing rate to 120 times a minute. Most of us could not keep that up very long, but that is what the heart does during exercise. So, A healthy human heart can increase its rate and force of contraction to meet the body`s need for more oxygen.

The primary function of the heart is as single pump for pumping the blood through the arteries, capillaries,and veins. As you known the blood transport oxygen,nutrients and has other important function as well, also the heart is the pump that keeps blood circulation properly.

Your heart is positioned obliquely between the lungs in the space of mediastinum. About twothirds of its bulk lies to the left side of the midline of the body. It is shaped like a blunt cone. It Is about the size of a closed fist. It is approximately 5 inches long (12 cm), 3.5 inches wide at its broadest point (9 cm), and 2.5 inches thick (6 cm).

B. Structure Of The Heart

The heart is composed of 3 layers of tissue (see picture 1) :
• Pericardium
• Myocardium
• Endocardium.













(pic : 1)



Pericardium

The pericardium is made up of two sacs. The outer sac consists of fibrous tissue and the inner of a continuous double layer of serous membrane. The outer fibrous sac is continuous with the tunica adventitia of the great blood vessels above and is adherent to the diaphragm below. Its inelastic, fibrous nature prevents overdistension of the heart.

The outer layer of the serous membrane is the parietal pericardium or lines the fibrous sac. The inner layer is the visceral pericardium, or epicardium, which is continuous with the parietal pericardium, is adherent to the heart muscle. A similar arrangement of a double membrane
forming a closed space is seen also with the pleura, the membrane enclosing the lungs.

The serous membrane consists of flattened epithelialcells. It is the secretes serous fluid into the space between the visceral and parietal layers which allows smooth movement between them when the heart beats. The space between the parietal and visceral pericardium is only a potential space. In health the two layers are in close association, with only the thin film of serous fluid between them. It is named pericardium serous (abaut 20-50 ml).


Myocardium

The myocardium is composed of specialised cardiac muscle found only in the heart. It is notunder voluntary control but, like skeletal muscle, cross-stripes are seen on microscopic examination. Each fibre (cell) has a nucleus and one or more branches. The ends of the cells and their branches are in very close contact with the ends and branches of adjacent cells.

Microscopically these 'joints', or intercalated discs, can be seen as thicker and darker lines than the ordinary cross-stripes. This arrangement will give heart muscle the appearance of being a sheet of muscle rather than a very large number of individual cells. Because of the end-to-end continuity of the fibres, each one does not need to have a separate nerve supply.When an impulse is initiated it spreads from cell to cell via the branches and intercalated discs over the whole 'sheet' of muscle that causing heart muscle contraction. So the 'sheet' arrangement of the myocardium enables the atria and ventricles to contract in a coordinated and efficient manner.

The myocardium is thickest at the apex and thins out towards the base. This reflects the amount of work each chamber contributes for pumping of the blood. The left ventricle is thickest than left ventricle. The atria and the ventricles are separated by a ring of fibrous tissue that does not conduct electrical impulses. Consequently, when a wave of electrical activity passes over the atrial muscle, it can only spread to the ventricles through the conducting system which bridges the fibrous ring from atria to ventricles.


Endocardium

This forms the lining of the myocardium and the heart valves. It is a thin, smooth and glistening membrane which permits smooth flow of blood inside the heart. It consists of flattened epithelial cells and connected with the endothelium that lines the blood vessels.



C. The Chambers of the Heart

The four chambers of the heart are made of cardiac muscle called the myocardium. The chambers are lined with endocardium, simple squamous epithelium that also covers the valves of the heart and continues into the vessels as their lining (endothelium). The important physical characteristic of the endocardium is not thinness, but rather its smoothness.
This very smooth tissue prevents abnormal blood clotting, because clotting would be initiated by
contact of blood with a rough surface.

The upper chambers of the heart are the right and left atria (or atrium), which have relatively thin walls and are separated by a common wall of myocardium called the interatrial septum. The lower chambers are the right and left ventricles, which have more thicker walls than atrial wall and separated by the interventricular septum. Look at the picture below, the atria receive blood, either from the body or the lungs, and the ventricles pump blood to either the lungs or the
body.(see picture 2)















(pic : 2)



Right Atrium

The two large caval veins return blood from the body to the right atrium. The superior vena cava carries blood from the upper body, and the inferior vena cava carries blood from the lower body and sinus coronary from the heart itself. From the right atrium, blood will flow through the right atrioventricular (AV) valve, or tricuspid valve, into the right ventricle. The tricuspid valve is made of three flaps (or cusps) of endocardium reinforced with connective tissue. The general purpose of all valves in the circulatory system is to prevent backflow of blood during or abaut to systolic occur.

The specific purpose of the tricuspid valve is to prevent backflow of blood from the right ventricle to the right atrium when the right ventricle contracts. As the ventricle contracts, blood is forced behind the three valve flaps, forcing them upward and together to close the valve.


Left Atrium

The left atrium receives blood from the lungs, by way of four pulmonary veins. This blood will then flow into the left ventricle through the left atrioventricular (AV) valve, also called the mitral valve or bicuspid (two flaps) valve. The mitral valve prevents backflow of blood from the left ventricle to the left atrium when the left ventricle contracts.

Another function of the atria is the production of a hormone involved in blood pressure maintenance. When the walls of the atria are stretched by increased blood volume or blood pressure, the cells produce atrial natriuretic peptide (ANP), also called atrial natriuretic hormone (ANH). (The ventricles of the heart produce a similar hormone called B-type natriuretic peptide, or BNP, but we will use ANP as the representative cardiac hormone.) ANP decreases the reabsorption of sodium ions by the kidneys, so that more sodium ions are excreted in urine and retained some potassium.


Right Ventricle

When the right ventricle contracts, automaticlly the tricuspid valve will closes and the blood is pumped to the lungs through the pulmonary artery (or trunk). At the junction of this large artery and the right ventricle is the pulmonary semilunar valve (or more simply, pulmonary valve). Its three flaps are forced open when the right ventricle contracts and pumps blood into the pulmonary artery. When the right ventricle relaxes, blood tends to come back, but this fills the valve flaps and closes the pulmonary valve to prevent backflow of blood into the right ventricle. Projecting into the lower part of the right ventricle are columns of myocardium called papillary muscles. Strands of fibrous connective tissue, the chordae tendineae, extend from the papillary muscles to the flaps of the tricuspid valve. When the right ventricle contracts, the papillary muscles also contract and pull on the chordae tendineae to prevent inversion of the tricuspid valve. So If you have ever had your umbrella blown inside out by a strong wind, you will see what would happen if the flaps of the tricuspid valve were not anchored by the chordae tendineae and papillary muscles.


Left Ventricle

The walls of the left ventricle are thicker than those of the right ventricle, which enables the left ventricle to contract more forcefully. The left ventricle pumps blood to the body through the aorta, the largest artery of the body. At the junction of the aorta and the left
ventricle is the aortic semilunar valve (or aortic valve). This valve is opened by the force of contraction of the left ventricle, which also closes the mitral valve.

The aortic valve closes when the left ventricle relaxes, to prevent backflow of blood from the aorta to the left ventricle. When the mitral (left AV) valve closes, it prevents backflow of blood to the left atrium; the flaps of the mitral valve are also anchored by chordae tendineae and papillary muscles. All of the valves are connected to the fibrous skeleton of the heart. This is fibrous connective tissue that anchors the outer edgesof the valve flaps and keeps the valve openings from stretching. It also separates the myocardium of the atria and ventricles and prevents the contraction of the atria from reaching the ventricles except by way of the normal conduction pathway.


D. Artery Coronary

The right and left coronary arteries are the first branches of the ascending aorta, just on the aortic semilunar valve. The two arteries branch into smaller arteries and arterioles, then to capillaries. The coronary capillaries merge to form coronary veins, which empty blood into a large coronary sinus that returns blood to the right atrium. (see picture 3)
The purpose of the coronary vessels is to supply blood to the myocardium itself, because oxygen is essential for normal myocardial contraction. If a coronary artery becomes obstructed, by a blood clot for example, part of the myocardium becomes ischemic, that is the deprived of its blood supply.

Prolonged ischemia will create an infarct, an area of necrotic (dead) tissue. This is a myocardial infarction, commonly called a heart attack.














(pic : 3)



D. Cardiac Cycle

The function of the heart is to maintain a constant circulation of blood throughout the body which needed for metabolism. The heart acts as a pump and its action consists of a series of events known as the cardiac cycle. During each heartbeat, or cardiac cycle, the heart contracts and then relaxes. The period of contraction is called systole and that of relaxation, diastole.

Stages of the cardiac cycle
The normal number of cardiac cycles per minute ranges from 60 to 80. Taking 74 as an example each cycle lasts about 0.8 of a second and consists of:

• atrial systole — contraction of the atria
• ventricular systole — contraction of the ventricles
• complete cardiac diastole — relaxation of the atria and ventricles.

It does not matter at which stage of the cardiac cycle a description starts. For convenience the period when the atria are filling has been chosen. The superior vena cava and the inferior vena cava transport deoxygenated blood into the right atrium at the same time as the four pulmonary veins conveyoxygenated blood into the left atrium. The atrioventricular valves are open and blood flows through to the ventricles.

The SA node triggers a wave of contraction that spreads over the myocardium of both atria, emptying the atria and completing ventricular filling (atrial systole 0.1 s). When the wave of contraction reaches the AV node it is stimulated to make an impulse which fastly or very fast spreading to the ventricular muscle via the AV bundle, the bundle branches and Purkinje fibres. This results in a wave of contraction which sweeps upwards from the apex of the heart and across the walls of both ventricles pumping the blood into the pulmonary artery and the aorta (ventricular
systole 0.3 s). The high pressure generated during ventricular contraction is greater than that in the aorta and forces the atrioventricular valves to close, preventing backflow of blood into the atria

After contraction of the ventricles there is complete cardiac diastole, a period of 0.4 seconds, when atria and ventricles are relaxed. During this time the myocardium
recovers until it is able to contract again, and the atria refill in preparation for the next cycle.
The valves of the heart and of the great vessels open and close according to the pressure within the chambers of the heart.

The AV valves are opened while the ventricular muscle is relaxed during atrial filling and systole. When the ventricles contract there is a gradual increase in the pressure in these chambers, and when it rises above atrial pressure the atrioventricular valves close. When the ventricular
pressure rises above that in the pulmonary artery and in the aorta, the pulmonary and aortic valves open and blood flows into these vessels. When the ventricles relax and the pressure within them falls, the reverse process occurs. First the pulmonary and aortic valvesclose, then the atrioventricular valves open and the cycle begins again. This sequence of opening and closing valves ensures that the blood flows in only one direction.


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