348 terms

Cardiovascular System

Chapter 8
What is the cardiovascular system composed of?
the heart and blood vessels
Where is the heart located?
the mediastinum, between the lungs
What is the main characteristic of an artery?
they carry oxygenated blood away from the heart to all cells in the body
What is a capillary?
a microscopic vessel that branches out of the arteries
What is the function of a capillary?
to exchange products between blood and body cells
What is a venule?
formed by capillaries merging together
What is a vein?
formed by venules merging together, carry blood back to the heart
What are the three major blood vessels?
arteries, capillaries, and veins
Why are the walls of an artery thicker than a vein?
to withstand the amount of pressure that results from the contractions of the heart
What are the three layers of the wall of an artery?
the tunica externa, tunica media, and tunica intima
What is the tunica externa?
the outer coating of a vein or artery, composed of connective tissue that provides strength and flexibility
What is the tunica media?
the middle layer of a vein or artery, composed of smooth muscle
What is the function of the tunica media?
to alter the size of the lumen of the vessel, which causes either vasoconstriction (narrowing) or vasodilation (widening) in the vessel
What is the tunica intima?
the thin, inner lining of the lumen of the vessel, composed of endothelial cells that provide a smooth surface inside the vein or artery
Autonomic nervous system (ANS)
portion of the nervous system that regulates involuntary actions, such as heart rate, digestion, and peristalsis
thin, flattened structure; term used to describe the leaf-shaped structures that compose a heart valve
tubular space or channel within any organ or structure of the body; space within an artery, vein, intestine, or tube
backflow or ejecting of contents through an opening
circular muscle found in a tubular structure or hollow organ that constricts or dilates to regulate passage of substances through its opening
narrowing of the lumen of a blood vessel that limits blood flow, usually a result of diseases, medications, or by physiological processes
widening of the lumen of a blood vessel caused by the relaxing of the muscles of the vascular walls
state of being sticky or gummy
the surge of blood felt in the arteries when blood is pumped from the heart
Why does a cut or severed artery lead to profuse bleeding?
the pressure against the arterial walls
What does arterial blood contain?
blood containing a high concentration of oxygen
small arteries
microscopic vessels which branch from the arterioles, join the arterial system with the venous system
What is the function of the capillaries?
to exchange water, respiratory gases, macromolecules, metabolites, and waste between the blood and adjacent cells
What are capillaries composed of?
a single layer of endothelial cells
Why does blood flow slowly through the capillaries?
their vast number, allows sufficient time for exchange of necessary substances
What is the function of a vein?
to carry deoxygenated blood back to the heart
What structures join to form the veins?
Where do venules develop from?
the union of capillaries
Why is the amount of pressure in veins less that in arteries?
because the arteries absorb most of the pressure exerted from the heart
What methods do veins use to return blood to the heart?
skeletal muscle contractions, gravity, respiratory activity, and valves
What is a valve?
the small structures within veins that prevent the backflow of blood
What blood vessels use peristalsis for transporting blood through the body?
veins, especially large veins
blood with a low concentration of oxygen
What is the characteristic color of oxygenated blood?
bright red
What is the characteristic color of deoxygenated blood?
What is the heart?
a muscular pump that propels blood to the entire body through a closed vascular system
Where (besides the mediastinum) is the heart located?
the pericardium sac
What are the tissue layers of the heart?
endocardium, myocardium, and epicardium
serous membrane that lines the four chambers of the heart and its valves and is continuous with the endothelium of the arteries and veins
the middle, muscle layer of the heart
the outermost layer of the heart
What are the four chambers that the heart is divided into?
right atrium, left atrium, right ventricle, and left ventricle
What is the function of the right and left atrium?
to collect blood
What are the two upper chamber of the heart?
right and left atrium
What is the function of the right and left ventricle?
to pump blood away from the heart
What are the two lower chambers of the heart?
right and left ventricle
Where does the right ventricle pump blood to?
the lungs, for oxygenation
Where does the left ventricle pump blood to?
throughout the entire body
Systemic Circulation
the process by which the left ventricle pumps oxygenated blood throughout the entire body
Pulmonary Circulation
the process by which the right ventricle pumps deoxygenated blood to the lungs for oxygenation
The right atrium receives deoxygenated blood from what two veins?
superior and inferior vena cava
superior vena cava
collects and carries deoxygenated blood from the upper body
inferior vena cava
collects and carries deoxygenated blood from the lower body
tricuspid valve
the valve in which deoxygenated blood passes from the right atrium to the right ventricle
How many leaflets does the tricuspid valve consist of?
When the heart contracts, blood leaves the right ventricle by way of what two structures?
the left and right pulmonary arteries
When the heart contracts and blood passes through the pulmonary arteries, what valve closes to prevent regurgitation?
the pulmonic valve, a.k.a the pulmonary semilunar valve
What function do the right and left pulmonary veins have?
they carry oxygenated blood back to the heart through the left atrium
mitral (bicuspid) valve
consists of two leaflets, the valve in which oxygenated blood passes from the left atrium to the left ventricle
the largest artery in the body, oxygenated blood leaves the heart through this artery upon contraction of the left ventricle
Aortic Semilunar Valve
contained in the aorta, prevents regurgitation of blood back into the left ventricle from the aorta
Aortic Valve
contained in the aorta, prevents regurgitation of blood back into the left ventricle from the aorta
Right Coronary Artery
the artery which vascularizes the right side of the heart
Left Coronary Artery
the artery which vascularizes the left side of the heart
What two arteries does the left coronary artery divide into?
the left anterior descending artery and the circumflex artery
What is the only type of vein which carries oxygenated blood?
the pulmonary veins
conduction tissue
specialized cardiac tissue with the sole function of initiating and spreading contraction impulses within the heart
What are the four masses of highly specialized cells within the heart that form the conductive tissue?
Sinoatrial (SA) node, atrioventricular (AV) node, bundle of His (AV bundle), Purkinje fibers
What is known as the "pacemaker" of the heart?
the Sinoatrial node (SA node)
Which part of the conductive tissue receives the impulses discharged from the SA node?
The atrioventricular (AV) node
What is the function of the atrioventricular (AV) node?
to cause the atria to contract by receiving electrical impulses from the sinoatrial (SA) node
What is the function of the bundle of His (AV bundle)?
to relay impulses from the AV node to the Purkinje fibers
Where is the SA node located?
in the upper portion of the right atrium
Where is the AV node located?
at the base of the right atrium
What is the function of the Purkinje fibers?
to transmit electrical impulses to the ventricles, causing them to contract
What is an electrocardiograph?
an instrument used to detect the weak electrical current generated by the conduction system within the heart
What does the P wave denote?
the depolarization of the atria
What does the QRS complex denote?
the depolarization of the ventricles
What does the T wave denote?
the repolarization of the ventricles
What does the term depolarization mean?
What does the term repolarization mean?
What does blood pressure (BP) measure?
the force of blood against arterial walls during the systolic and diastolic phases of the heartbeat
What is the systolic phase of a heartbeat?
the contraction phase, when blood is forced out of the heart, produces the maximum force
What is the diastolic phase?
the relaxation phase, when the ventricles are filling with blood, produces the weakest force
Which measurement is given first when displaying blood pressure?
systolic pressure
Which measurement is given lastly when displaying blood pressure?
diastolic pressure
What is hypertension?
a consistently elevated blood pressure
What is hypotension?
decreased blood pressure
What are the factors that influence blood pressure?
resistance of blood flow in blood vessels, pumping action of the heart, viscosity of blood, quantity of blood in the vascular system
Where does gas exchange occur in a fetus?
the placenta
Where does the procurement of nutrients occur in a fetus?
the placenta
Where does the elimination of metabolic waste occur in a fetus?
the placenta
What factors influence blood pressure?
resistance of flow in the vessels, pumping action of the heart, viscosity of blood, elasticity of arteries, and the quantity of blood in the vascular system
What is the umbilical cord?
contains 2 arteries, carries deoxygenated blood from the fetus to the placenta, and after oxygenation in the placenta the blood returns through the umbilical vein
Most of the blood in the umbilical vein enters the inferior vena cava of the fetus through what duct?
The ductus venosus
After the blood enters the inferior vena cava of the fetus where does it travel to?
The right atrium of the heart
After entering the right atrium, where does most of the blood travel to in a fetus CV system?
The left atrium
What is the small opening in a fetal atrial septum which allows blood to travel from the right atrium to the left?
The foramen ovale, which closes shortly after birth
From the left atrium, where does blood travel to in a fetal CV system?
The left ventricle
After leaving the left ventricle, where does blood exit the heart in order to travel to the head upper extremities in a fetus?
The aorta
Because fetal lungs are nonfunctional, most of the blood in the pulmonary arteries is shunted to the aorta through what duct?
The ductus arteriosus
What happens to the ductus arteriosus immediately after birth?
It withers and closes off to allow blood to freely travel from the pulmonary arteries to the lungs
As circulation increases in the neonate, the increase of blood flow to the right atrium forces what opening to close which establishes normal circulation?
The foramen ovale
widened blood vessel
the suture of an aneurysm
vessel (usually blood or lymph)
surgical repair of a vessel
vessel (usually blood or lymph)
inflammation of (blood) vessels
narrowing of the aorta
narrowing, stricture
rupture of an artery
inflammation of an arteriole
enlargement of the atrium
fatty plaque
tumor composed of fatty plaque
enlargement of the heart
a record of the electrical (impulses) of the heart
embolus (plug)
removal of an embolus
blood vessel
tumor of blood vessels
pertaining to the heart muscle
pertaining to
expansion of a vein
standing still of (blood in a) vein
standing still of (blood in a) vein
standing still
hardening; sclera (white of eye)
abnormal condition of hardening of the artery
abnormal condition; increase (used primarily with blood cells)
forming an opening in a septum
forming an opening (mouth)
resembling a pulse
narrowing, stricture
pertaining to a narrowing or stricture
pertaining to
blood clot
destruction of a blood clot
separation; destruction; loosening
ventricle (of the heart or brain)
pertaining to a ventricle (chamber of the heart or brain)
pertaining to
record, writing
record of an artery
instrument for recording
instrument for recording electrical (activity) of the heart
process of recording
process of recording (an image of) a vessel
without a pulse
without a pulse
narrowing, stricture
narrowing of the aorta
slow heart (beat)
in, within
relating to (the area) within a vessel
relating to the (area) outside a vessel
pertaining to (the area) around the heart
rapid heart (beat)
across the septum
What predisposition are many cardiac disorders like coronary artery disease and valvular disorders associated with?
What two records are essential to diagnose cardiovascular diseases?
A complete history, as well as a physical examination of the patient
What are the common symptoms of cardiovascular diseases?
angina, palpitations, dyspnea, arrhythmias, and syncope
What is angina?
chest pain
What is syncope?
loss of consciousness
Due to the general nature of the signs and symptoms of cardiovascular disorders, what kind of tests are required to confirm or rule out a suspected disease?
both invasive and noninvasive
What factors are important qualities in differentiating the various forms of cardiovascular disease?
Location, duration, pattern of radiation, and severity of pain
What is cardiology?
the medical specialty concerned with disorders of the CV system
What is the title for a physician who treats disorders of the CV system?
What is arteriosclerosis?
The hardening of arterial walls that causes them to become thickened and brittle
What causes arteriosclerosis?
A build up of atheroma
What is atheroma composed of?
a plaque-like substance of cholesterol, lipids, and cellular debris
What is the term for the hardening of the atheroma?
What do the arterial walls lose after the presence of atherosclerosis?
Their elasticity
What is a thrombus?
A blood clot
What is a thrombus knows as when it dislodges and travels throughout the vascular system?
An embolus
What is the plural term for an embolus?
What can an embolus cause in venous circulation?
possibly death
What can an embolus cause in arterial circulation if it lodges in a capillary bed?
What is infarction?
the localized death of tissue
What is an aneurysm?
When plaque weakens a vessel wall to such an extent that it forms a bulge that may rupture
What kinds of arteries are affected by arteriosclerosis?
large or medium sized, including the abdominal aorta, the coronary, cerebral, renal, and femoral arteries
Where are the femoral arteries located?
In the legs
What are some of the major risk factors of developing arteriosclerosis?
Hypercholesterolemia, age, family history, smoking, hypertension, and diabetes
What is hypercholesterolemia?
An elevated cholesterol level
What is a common treatment for arteriosclerosis?
What is an endarterectomy?
A surgical procedure in which occluding material and plaque are removed from the innermost layer of the artery
What are the three types of aneurysms?
fusiform, saccular, and dissecting
What is coronary artery disease (CAD)?
Failure of the coronary arteries to deliver an adequate supply of blood to the myocardium
What is the major cause of CAD?
What is ischemia?
Oxygen deficiency in localized areas (of the heart, due to partial occlusions in the arteries)
What are the clinical signs and symptoms of myocardial infarction (MI)?
intense angina, diaphoresis, pallor, and dyspnea
What two conditions may also accompany an MI?
bradycardia or tachycardia
What are the highly specific cardiac enzymes that are releases when the heart undergoes necrotic changes?
troponin T, troponin I, and creatine kinase (CK)
When angina due to an MI cannot be controlled with medication, what surgical procedure may be necessary?
Percutaneous transluminal coronary angioplasty (PTCA)
What is a PCTA?
a deflated balloon is passed through a small incision in the skin and into the diseased blood vessel, when the balloon inflates it forces open the channel by pressing the occluding material against the lumen walls
What is commonly inserted into the artery after a PTCA procedure?
a stent, to keep the artery opened
What is a coronary artery bypass graft (CABG)?
a more invasive procedure than a PTCA, involves rerouting blood around the occluded area using a vein graft that bypasses the obstruction
What two structures are linked in a CABG to reestablish blood flow to the heart muscle?
the aorta and the coronary artery (below the blocked area)
What is endocarditis?
an inflammation of the inner lining of the heart and its valves
What are the two general natures of endocarditis?
noninfective (thrombi formation), or infective (caused by microorganisms)
Although the infecting organism can be viral or fungal, what is the usual culprit of infective endocarditis?
What are some predisposing factors of endocarditis?
congenital valvular defects, scarlet fever, rheumatic fever, calcified bicuspid or aortic valves, mitral valve prolapse, and prosthetic valves
What is bacteremia?
bacteria traveling in the bloodstream
What are vegetations?
small masses composed of fibrin and platelets, caused by bacteremia lodging in weakened heart tissue that results from endocarditis
Where do vegetations usually collect?
on the leaflets of the valves within the heart and their cords
What do vegetations on the valves cause?
regurgitation of blood or scarring
If a vegetation embolizes, what organs can it travel to?
brain, lungs, kidney, or spleen
What happens to the valves of the heart when they become scarred by vegetations?
stenosis and insufficiency
What is used when damage is to extensive to a valve and surgery cannot be used?
a mechanical or bioprosthetic valve
What treatment is given to patients who are susceptible to endocarditis in order to protect against infection prior to invasive procedures?
prophylactic (antibiotic) treatment
Because many bacteria normally found in the mouth are also responsible for endocarditis, prophylactic treatment is also essential for what procedures?
tooth removal, root canal procedures, and even routine cleaning
What are varicose veins?
Veins which are enlarged, twisted, and superficial
What causes varicose veins?
incompetent valves within the veins which fail to prevent the backflow of blood, the blood then accumulates and the vein becomes engorged and distended
What is the term for the swelling in surrounding tissues which occurs from excess fluid seeping from a vein?
varicose veins in the esophagus
varicose veins in the rectum
Where do varicose veins most commonly occur?
The greater and lesser saphenous regions of the lower legs
What are the different types of varicose veins?
reticular, and telangiectases ("spider") veins
What are the characteristics of reticular veins?
small, blue veins seen through the skin
What are the characteristics of telangiectases veins?
short, fine lines, starburst clusters, or weblike mazes
What are some treatments for extensive varicose veins?
laser ablation, microphlebectomies, sclerotherapy, and occasionally ligation and stripping for heavily damaged and diseased veins
What are some treatments for mild varicose veins?
elastic stockings, rest periods during which the legs are elevated
What is the most common type of primary tumor in the heart?
What is a myxoma?
a tumor composed of mucous connective tissue
Are most myxomas benign or malignant?
Where do myxomas usually originate?
the left atrium
What is pulmonary edema?
fluid in the lungs
What is arthralgia?
joint pain
What is the most common cause of malignant tumors in the heart?
a primary tumor that has metastasized to the heart from another area of the body
What is the most common type of malignant tumor in the heart?
malignant melanoma
What are the two less common sites in which a malignancy metastasizes and spreads to the heart?
bone marrow and lymphatic tissue
Treatment of a metastatic tumor of the heart involves what?
treating the primary tumor in the area it originated
localized, abnormal dilation of a vessel, usually an artery
condition of being stopped or bringing to a stop
Cardiac arrest
loss of effective cardiac function, which results in cessation of circulation
Circulatory arrest
cessation of the circulation of blood due to ventricular standstill or fibrillation
inability of the heart to maintain a normal sinus rhythm, possibly including a rapid or slow heartbeat or "skipping" a beat
inability of the heart to maintain a normal sinus rhythm, possibly including a rapid or slow heartbeat or "skipping" a beat
Soft blowing sound heard on auscultation, possibly due to vibrations associated with the movement of blood, valvular action, or both
Soft blowing sound heard on auscultation, possibly due to vibrations associated with the movement of blood, valvular action, or both
any disease or weakening of heart muscles that diminish cardiac function
thin, flexible, hollow plastic tube that is small enough to be threaded through a vein, artery, or tubular structure
narrowing of a vessel, especially the aorta
Deep Vein Thrombosis (DVT)
blood clot that forms in the deep veins of the body, especially those in the legs or thighs
Ejection Fraction (EF)
calculation of how much blood a ventricle can eject with one contraction
Heart Failure (HF)
failure of the heart to supply an adequate amount of blood to tissue and organs
mass of undissolved matter (foreign object, air, gas, tissue, thrombus) circulating in blood or lymphatic channels until it becomes lodged in a vessel
quivering or spontaneous muscle contractions, especially of the heart, causing ineffectual contractions
arrest of bleeding or circulation
Excessive amounts of lipids (cholesterol, phospholipids, and triglycerides) in the blood
Hypertension (HTN)
Common disorder characterized by elevated blood pressure persistently exceeding 140mm Hg systolic or 90mm Hg diastolic
Primary HTN
hypertension in which there is no identifiable cause; also called essential hypertension
Secondary HTN
hypertension that results from an underlying, identifiable, commonly correctable cause
Hypertensive Heart Disease
any heart disorder caused by prolonged hypertension, including left ventricular hypertrophy, coronary artery disease, cardiac arrhythmias, and heart failure
Implantable Cardioverter-defibrillator (ICD)
Implantable battery-powered device that monitors and automatically corrects ventricular tachycardia or fibrillation by sending electrical impulses to the heart
area of tissue that undergoes necrosis following cessation of blood supply
local and temporary deficiency of blood supply due to circulatory obstruction
Mitral Valve Prolapse (MVP)
common and occasionally serious condition in which the leaflets of the mitral valve prolapse into the left atrium during systole causing a characteristic murmur heard on auscultation
chemical radioactive material used as a tracer to follow a substance through the body or a structure
sensation that the heart is not beating normally, possibly including "thumping", "fluttering", "skipped beats", or a pounding feeling in the chest
Patent Ductus Arteriosus
Failure of the ductus arteriosus to close after birth, allowing blood to flow from the aorta into the pulmonary (lung) artery
Circulation of blood through tissues or the passage of fluids through vessels of an organ
Tetralogy of Fallot
congenital anomaly consisting of four elements: (1) pulmonary artery stenosis; (2) inter-ventricular septal defect; (3) transposition of of the aorta; (4) right ventricular hypertrophy caused by increased workload of the right ventricle
slender or threadlike device used to hold open vessels, tubes, or obstructed arteries
blood clot that obstructs a vessel
Cardiac Catheterization (CC)
passage of a catheter into the heart through a vein or artery to provide a comprehensive evaluation of the heart
Electrocardiogram (ECG, EKG)
graphic line recording that shows the spread of electrical excitation to the different parts of the heart using small metal electrodes applied to the chest, arms, and legs
Holter monitor test
ECG taken with a small portable recording system capable of storing up to 24 hours of ECG tracings
Nuclear monitor test
ECG that utilizes a radioisotope to evaluate coronary blood flow
Stress test
ECG taken under controlled exercise stress conditions
Cardiac Enzyme Studies
blood test that measures troponin T, troponin I, and creatine kinase
Lipid Panel
series of tests (total cholesterol, high density lipoprotein, low density lipoprotein, and triglycerides) used to assess risk factors of ischemic heart disease
Radiographic imaging of the heart and blood vessels after injection of a contrast dye
Coronary Angiography
angiography to determine the degree of obstruction of the arteries that supply blood to the heart
Digital Subtraction Angiography (DSA)
angiography in which two radiographic images are obtained and digitally subtracted from each other leaving only an image of vessels with contrast
Radiological examination of the aorta and its branches following injection of a contrast medium via a catheter
Echocardiography (ECHO)
noninvasive diagnostic method that uses ultrasound to visualize internal cardiac structures and produce images of the heart
Doppler Ultrasound
Noninvasive adaptation of ultrasound technology in which blood flow velocity is assessed in different areas of the heart
Magnetic Resonance Imaging (MRI)
noninvasive technique that uses radio waves and a strong magnetic field, rather than an x-ray beam, to produce multi-planar cross-sectional images of blood vessels
Multiple-Gated Acquisition
Nuclear procedure that uses radioactive tracers to produce movie-like images of the structures of the heart, including the myocardium and the mitral and tricuspid valves
Imaging technique that provides a graphic display of heart sounds and murmurs during the cardiac cycle
diagnostic procedure that uses radiation emitted by the body after an injection of radioactive substances to create images of various organs or identify body functions and diseases
Thallium study (resting)
Scintigraphy procedure that uses injected radioactive thallium and records the uptake of the isotope with a gamma camera to produce an image
Radiography of a vein after injection of a contrast medium to detect incomplete filling of a vein, which indicates obstruction
Procedure to restore normal rhythm of the heart by applying a controlled electrical shock to the exterior of the chest
technique used to block blood flow to a site by passing a catheter to the area and injecting a synthetic material or medication specially designed to occlude the blood vessel
Injection of a chemical irritant (sclerosing agent) into a vein to produce inflammation and fibrosis that destroys the lumen of the vein
Procedure that alters a vessel through surgery or dilation of the vessel using a balloon catheter
removal of material from an occluded vessel using a specially designed catheter fitted with a cutting and grinding device
removal and examination of a small piece of tissue for diagnostic purposes
Arterial Biopsy
removal and examination of a segment of an arterial vessel wall to confirm inflammation of the wall or arteritis, a type of vasculitis
Catheter Ablation
destruction of conduction tissue of the heart to interrupt the abnormal conduction pathway causing the arrhythmia, thus allowing normal heart rhythm to resume
surgical separation of the leaflets of the mitral valve, which have fused together at their "commissures" (points of touching)
Laser Ablation
Procedure used to remove or treat varicose veins
Ligation and Stripping
Tying a varicose vein (ligation) followed by removal (stripping) of the affected segment
Open Heart Surgery
Surgical procedure performed on or within the exposed heart, usually with the assistance of a heart-lung machine
Puncturing of the pericardium to remove excess fluid from the pericardial sac or to test for protein, sugar, and enzymes or determine the causative organisms of pericarditits
Destruction of a blood clot using anti-clotting agents called "clot-busters", such as tissue plasminogen activator
Intravascular Thrombolysis
Infusion of a thrombolytic agent into a vessel to dissolve a blood clot
Incision of a valve to increase the size of the opening; used in treating mitral stenosis
Puncture of a vein by a needle attached to a syringe or catheter to withdraw a specimen of blood; also called phlebotomy
Angiotensin-Converting Enzyme Inhibitors
lower blood pressure by inhibiting the conversion of angiotensin I (an active enzyme) to angiotensin II (a potent vasoconstrictor)
prevent, alleviate, or correct cardiac arrhythmias (dysrhythmias) by stabilizing the electrical conduction of the heart
Block the effect of adrenaline on beta receptors, which slow nerve pulses that pass through the heart, therrby causing a decreased heart rate and contractility
Calcium Channel Blockers
Block movement of calcium (required for blood vessel contraction) into myocardial cells and arterial walls, causing heart rate and blood pressure to decrease
Act on kidneys to increase excretion of water and sodium
Dilate blood vessels of the heart, causing an increase in the amount of oxygen delivered to the myocardium, and decreased venous return and arterial resistance, which decreases myocardial oxygen demand and relieves angina
Peripheral Vasodilators
Treat peripheral vascular diseases, diabetic peripheral vascular insufficiency, and Raynaud disease
Lower cholesterol in the blood and reduce production in the liver by blocking the enzyme that produces it
abdominal aortic aneurysm
angiotensin-converting enzyme (inhibitor)
atrial fibrillation
aortic stenosis
atrial septal defect
arteriosclerotic heart disease
angiotensin sensitivity test