CHP. 6

If any of your coronary arteries become blocked, the blood supply to a part of your cardiac muscle is cut off_______ and the cells supplied by that artery die ________within minutes. This is a ______

(ischemia) (necrosis) myocardial infarction (MI) or a "heart attack."

Several diagnostic tests are used to measure heart health

. An electrocardiogram (ECG or EKG) is a paper record of the electrical signals of your heart. Cardiac stress testing is an exercise tolerance test that raises your heart rate through exercise (like jogging on a treadmill) and monitors its effect on cardiac function. Nuclear imaging of the heart, which involves the injection of a radioactive substance, can be used with the stress test. Echocardiography uses ultrasound waves to study cardiac function. Magnetic resonance imaging (MRI) can produce detailed images of the heart and identify sections of cardiac muscle that are not receiving an adequate blood supply. Cardiac catheterization detects pressure and blood flow patterns in the heart. A thin tube is inserted into a vein or artery and is then threaded into the heart under X-ray guidance. A coronary angiogram uses a contrast dye injected during cardiac catheterization to identify coronary artery blockages.

In order to keep your body alive, your heart must work all the time, without stopping. Its three most important functions are to:

1. Pump blood. As your heart contracts, it generates pressure that moves your blood through your blood vessels. 2. Route blood. Your heart essentially has two pumps: one on the right side that sends blood through the pulmonary circulation of your lungs and back to the second pump on your left side, which sends blood through the systemic circulation of your body. Your heart valves make this one-way flow of blood possible. 3. Regulate blood supply. The changing metabolic needs of your tissues and organs—for example, when you exercise—are met by changes in the rate and force of your heart's contractions.

Specialties

Cardiologists are medical doctors who specialize in disorders of the cardiovascular system. Cardiovascular surgeons are surgeons who specialize in surgery of the heart and the peripheral blood vessels. Cardiovascular technologists and technicians assist physicians in the diagnosis and treatment of cardiovascular disorders. Vascular technologists are practitioners who assist physicians by performing diagnostic and monitoring procedures using ultrasound. Cardiac sonographers or echocardiographers are technologists who use ultrasound to observe the heart chambers, valves, and blood vessels. Phlebotomists or phlebotomy technicians assist physicians by drawing patient blood samples for laboratory testing. Perfusionists are highly trained health care professionals who use the heart-lung machine during cardiac and other surgeries that require cardiopulmonary bypass.

DISORDERS OF THE HEART WALL

Endocarditis is an inflammation of the heart's lining, which is usually secondary to an infection elsewhere. Intravenous drug users and people with damaged heart valves are at high risk for endocarditis. Myocarditis is an inflammation of the heart muscle. It can be bacterial, viral, or fungal in origin, or can arise as a complication of other diseases like influenza. Pericarditis is inflammation of the covering of the heart. The inflammation causes an exudate (pericardial effusion) to be released into the pericardial space between the two layers of the pericardium. This interferes with the heart's ability to contract and expand normally, which reduces cardiac output (CO) and leads to a life-threatening condition called cardiac tamponade. Cardiomyopathy is a weakening of the heart muscle that makes it pump inadequately. This causes the heart to enlarge (cardiomegaly) and leads to heart failure.

3 LAYERS OF THE HEART

Endocardium: Connective tissue lining the inside of your heart. Myocardium: Cardiac muscle cells that contract to enable your heart to pump blood. Epicardium: An outer single layer of cells overlying a thin layer of connective tissue.

aneurysm

Greek dilation Circumscribed dilation of an artery or cardiac chamber

The most immediate need in the treatment of MI is to get blood and oxygen to the affected myocardium. This can be attempted in several ways:

Injection of clot-busting (thrombolytic) drugs: These drugs are injected within 3½ hours of the MI to dissolve the thrombus. Artery-cleaning angioplasty (percutaneous transluminal coronary angioplasty, or PTCA): A balloon-tipped catheter is guided to the blockage site and inflated. The inflated balloon expands the artery from the inside by compressing the plaque against the artery's walls. Stent placement: To reduce the likelihood that the artery will close up again (occlude), a wire-mesh tube, or stent, is placed inside the vessel. Drug-eluting stents are covered with a special medication to help keep the artery open. Cardioversion and defibrillation have been discussed earlier. Radiofrequency ablation uses a catheter with an electrode in its tip that is guided into the heart to destroy cells from which abnormal cardiac rhythms are originating. Coronary artery bypass surgery (CABG): Healthy blood vessels harvested from the leg, chest, or arm are used to bypass (detour) the blood around blocked coronary arteries. Heart transplant: The heart of a recently deceased person (donor) is transplanted into the recipient after the recipient's diseased heart has been removed.

vena cava venae cavae (pl)

R/CF ven/a vein R/cava cave One of the two largest veins in the body The two largest veins in the body (superior and inferior venae cavae)

thromboembolism

S/ R/CF R/ -ism condition thromb/o- clot -embol- plug A piece of detached blood clot (embolus) blocking a distant blood vessel

sclerotherapy sclerose (verb) sclerosis (noun)

S/ -therapy treatment R/CF scler/o- hardness S/ -ose full of R/ scler- hardness S/-osis condition Injection of a solution into a vein to thrombose it To harden or thicken Thickening or hardening of a tissue

cardiopulmonary resuscitation (CPR)

S/-ary pertaining to R/CF cardi/o- heart R/-pulmon- lung S/-ation a process R/-resuscit- revive from apparent death The attempt to restore cardiac and pulmonary function

capillary capillaries

S/-ary pertaining to R/capill- hairlike structure Minute blood vessel between the arterial and venous systems

electrocardiogram (ECG, EKG) electrocardiograph electrocardiography

S/-gram a record R/CF electr/o- electricity R/CF -cardi/o- heart S/-graph to record S/. -graphy process of recording Record of the electrical signals of the heart Machine that produces the electrocardiogram The method of recording and the interpretation of electrocardiograms

hemodynamics

S/-ics knowledge R/CF hem/o- blood R/-dynam- power The science of the blood flow through the circulation

palpate (verb) palpation (noun)

S/-ion action, condition R/palpat- touch, stroke Latin touch, stroke To examine with the fingers and hands Examination with the fingers and hands

thromboembolism

S/-ism condition R/CF thromb/o- clot R/ -embol- plug A piece of detached blood clot (embolus) blocking a distant blood vessel

phlebotomist phlebotomy

S/-ist specialist in R/CF phleb/o- vein R/ -tom- incise, cut S/ -tomy surgical incision Person skilled in taking blood from veins Withdrawing blood from a vein through a needle or catheter

cardiologist cardiology

S/-logist one who studies, specialist R/CF cardi/o- heart S/-logy study of A medical specialist in the diagnosis and treatment of the heart (cardiology) Medical specialty of diseases of the heart

sphygmomanometer

S/-meter instrument to measure R/CF sphygm/o- pulse R/CF -man/o- pressure Instrument for measuring arterial blood pressure

vein venous (adj) venogram

S/-ous pertaining to R/ven- vein S/ -gram recording R/CF ven/o- vein Latin vein Blood vessel carrying blood toward the heart Pertaining to a vein Radiograph of veins after injection of radiopaque contrast material

stethoscope

S/-scope instrument to examine R/CF steth/o- chest Instrument for listening to respiratory and cardiac sounds

edema (noun) edematous (adj)

S/-tous pertaining to R/edema- swelling Greek swelling Excessive accumulation of fluid in cells and tissues Pertaining to or affected by edema

endocardium endocardial (adj)

S/-um structure P/endo- inside R/-cardi- heart S/-al pertaining to The inside lining of the heart Pertaining to the endocardium

epicardium epicardial (adj)

S/-um structure P/epi- upon, above R/-cardi- heart S/ -al pertaining to The outer layer of the heart wall Pertaining to the epicardium

atrium atria (pl) atrial (adj)

S/-um structure R/atri- entrance, atrium S/ Chamber where blood enters the heart on both the right and left sides Pertaining to the atrium

Malfunctions of the valves on the right side of the heart are much less common than those on the left side.

Stenosis: The valve cannot open fully, and its opening is narrowed (constricted). Because blood cannot flow freely through the valve, it accumulates in the chamber behind the valve. Incompetence or insufficiency is a condition where the heart valve cannot close fully, allowing blood to leak or regurgitate (flow back) through the valve to the heart chamber from which it came. Mitral valve stenosis can occur following rheumatic fever. Because the blood cannot flow freely through the valve, the left atrium becomes dilated (enlarged). Eventually, chronic heart failure results. Mitral valve prolapse (MVP) occurs when the cusps of the valve bulge back into the left atrium when the left ventricle contracts. This allows blood to flow back into the atrium. Aortic valve stenosis is common in the elderly when the valves become calcified due to atherosclerosis. Blood flow into the systemic circulation is diminished, leading to dizziness and fainting. The left ventricle dilates, hypertrophies, ceases to beat strongly, and ultimately fails. Aortic valve incompetence initially produces few symptoms other than a murmur. Eventually the left ventricle is unable to cope with the excess volume of blood and fails. (Figure 6.12 enables you to review the locations of the valves and chambers.)

The pericardium is a double-layered connective tissue sac that surrounds and protects your heart.

T

The term circulatory system refers to your heart and blood vessels. It has two major divisions (see Figure 6.18):

The pulmonary circulation, which carries deoxygenated blood from the heart to the lungs, and returns oxygenated blood to the heart; and The systemic circulation, which supplies oxygenated blood to every organ except the lungs, and then returns deoxygenated blood to the heart, which pumps it into the pulmonary circulation.

The circulatory system has the following three functions:

Transportation. It carries oxygen, nutrients, hormones, and enzymes that diffuse from the blood into the cells. Waste products and carbon dioxide diffuse back from the cells into the system and are carried to the lungs, liver, and kidney for excretion. Homeostasis maintenance. The systemic circulation directs blood flow to the tissues to enable them to meet their metabolic needs. Blood pressure regulation. In the systemic circulation, the arteries' ability to expand and contract in coordination with the systole and diastole of the heartbeat maintains a steady flow of blood and blood pressure to the tissues.

An aneurysm is a localized dilation of an artery, and this commonly occurs in the Aneurysms can rupture, leading to severe bleeding and hypovolemic shock. Surgical repair consists of .....

abdominal aorta (Figure 6.21). excision of the aneurysm and replacement with a synthetic graft.

Intracranial aneurysms are

an important cause of bleeds into the cranial cavity and brain tissue.

Coronary artery disease occurs when the coronary arteries supplying blood to the myocardium are constricted by atherosclerotic plaques called

atheroma;This reduces the blood supply to the cardiac muscle. Platelet clumping can occur on the plaque and form a blood clot (coronary thrombosis). Atherosclerosis is the most common form of arteriosclerosis (hardening of the arteries), and it can lead to arteriosclerotic heart disease (ASHD).

Carotid artery disease affects the

carotid arteries—the two major arteries supplying the brain. They can be involved in arteriosclerosis and the deposition of plaque. This puts the patient at risk for a stroke. A carotid endarterectomy can be performed to surgically remove the plaque.

Because your heart beats continually and forcefully, it requires an abundant supply of oxygen and nutrients. To meet this need, your cardiac muscle has its own blood circulation called the

coronary circulation (Figure 6.3). This system of arteries arises directly from the aorta.

Raynaud disease is

episodes of spasm (following exposure to cold) of the small arteries supplying the fingers, hands, and feet. It can be associated with connective tissue disorders like scleroderma and lupus.

Cor pulmonale is

failure of the right ventricle to pump properly. Almost any chronic lung disease causing low blood oxygen (hypoxia) can cause this disorder.

The pulse is always part of a clinical examination because it can provide information about

heart rate, heart rhythm, and the state of the arterial wall by palpation (Figure 6.17). The most easily accessible artery is the radial artery at the wrist, where the pulse is usually taken.

Thromboangiitis obliterans (Buerger disease) is an

inflammatory disease of the arteries with clot formation, usually in the legs. The occlusion of arteries and impaired circulation lead to intermittent pain when walking, and a person will often limp to compensate.

Deep vein thrombosis (DVT)

is a thrombus formation in a deep vein. The increased pressure in the capillaries due to back pressure from the blocked blood flow in the veins creates a collection of fluid in the tissues called edema.

Thrombophlebitis

is an inflammation of the lining of a vein, allowing clots (thrombi) to form.

Blood pressure is the force the blood exerts on arterial walls as it is pumped around the circulatory system by the ____ ______. The pressure is measured using a sphygmomanometer and a stethoscope, usually at the ____ _____.

left ventricle. brachial artery (Figure 6.17).

cardiopulmonary resuscitation (CPR). The heart is located in the thoracic cavity between the lungs, in an area called the

mediastinum (Figure 6.1a). The heart is shaped like a blunt cone, pointing down and to the left. It rests at an angle with the majority of its mass to the left of the sternum

Angina pectoris (pain in the chest on exertion) is often the first symptom of a reduced oxygen supply to the

myocardium. Myocardial infarction (MI) is the death of myocardial cells, caused by the lack of blood supply (ischemia) when an artery eventually becomes blocked (occluded). If the ischemia is not reversed within 4 to 6 hours, the myocardial cells die (necrosis).

A major complication of thrombus (clot) formation is that a piece of the clot can break off (embolus) and be carried in the bloodstream to another organ where it can block blood flow. It often lodges in the lungs, causing a

pulmonary embolus or mass

Smaller, more superficial varicose veins are called ________. Treatments offered include________ and _______. in which solutions that scar the veins are injected into them. Collateral circulations-

spider veins. laser technology and sclerotherapy, develop to take the blood through alternative routes.

Varicose veins are

superficial veins that have lost their elasticity and appear swollen and tortuous;). Their valves become incompetent, and blood flows backward and pools.