Cardiovascular Disorders: Atherosclerosis
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Questions and Answers

What are some general manifestations of acute coronary syndrome?

  • Gradual onset
  • Mild and diffuse pain
  • Increased appetite
  • Severe and crushing pain, usually substernal, radiating to the left arm, neck, or jaw (correct)

    • What is the main cause of death in ST-elevation myocardial infarction (STEMI)?

    Ventricular fibrillation

    A 'silent MI' occurs when a person doesn’t experience any symptoms or has _____ symptoms.

    atypical

    Decreased cardiac output can lead to cardiogenic shock.

    <p>True</p> Signup and view all the answers

    What is atherosclerosis?

    <p>Fibrous fatty lesions in arteries</p> Signup and view all the answers

    What is the principal cause of atherosclerosis?

    <p>Endothelial cell damage</p> Signup and view all the answers

    Elevated cholesterol is a predisposing risk factor for atherosclerosis.

    <p>True</p> Signup and view all the answers

    __________ is known as the third of all deaths in industrialized West due to ischemic heart disease.

    <p>Coronary artery disease</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Stable angina = Chest pain caused by temporary myocardial ischemia Unstable angina = Chest pain due to plaque surface disruptions and small thromboses Myocardial infarction = Immediate result of complete coronary occlusion leading to ischemic injury and necrosis</p> Signup and view all the answers

    What is the main cause of right heart failure?

    <p>Inability of right ventricle to move deoxygenated blood from systemic circulation into the pulmonary circulation.</p> Signup and view all the answers

    What is the primary effect of ventricular hypertrophy on contractility?

    <p>Increases contractility</p> Signup and view all the answers

    Hypertrophic cardiomyopathy can increase wall thickness and reduce chamber size, leading to ____________.

    <p>decreased diastolic relaxation</p> Signup and view all the answers

    Left heart failure can lead to right heart failure.

    <p>True</p> Signup and view all the answers

    Match the following compensatory mechanisms with their effects:

    <p>Sympathetic Nervous System activation = Increases blood pressure and cardiac output RAAS activation = Increases afterload and preload, putting more strain on the heart Hypertrophy = Can lead to thickening or thinning of ventricle walls, affecting contraction</p> Signup and view all the answers

    What are the three shock states that share the mechanism of massive vasodilation?

    <p>Neurogenic, Anaphylactic, Septic</p> Signup and view all the answers

    What is the most common type of vasodilatory shock?

    <p>Septic shock</p> Signup and view all the answers

    Primary hypertension is most commonly due to genetics and the environment.

    <p>True</p> Signup and view all the answers

    _____ is a specific decrease in blood pressure within 3 minutes of moving to a standing position.

    <p>Orthostatic (Postural) Hypotension</p> Signup and view all the answers

    Match the following arterial diseases with their descriptions:

    <p>Atherosclerosis = Leading cause of coronary artery and cerebrovascular disease Hypertension = Consistent elevation of systemic arterial blood pressure Orthostatic Hypotension = Specific decrease in blood pressure upon standing Aneurysm = Local outpouching of vessel or heart wall</p> Signup and view all the answers

    What is the role of IV fluids in the treatment of shock?

    <p>To expand blood volume</p> Signup and view all the answers

    What are some risk factors for varicose veins?

    <p>standing long periods, crossing legs at the knee, age, female gender, family history, obesity, pregnancy, deep venous thrombosis, and previous leg injury</p> Signup and view all the answers

    What can happen to the remaining upstream valves in the vein when edema develops in the surrounding tissue?

    <p>They become damaged and unable to maintain normal venous pressure</p> Signup and view all the answers

    Chronic Venous Insufficiency (CVI) can lead to impaired nutrition, edema, and venous hypertension.

    <p>True</p> Signup and view all the answers

    What is a possible complication of varicose veins that involves inadequate venous return over a long period of time?

    <p>Chronic Venous Insufficiency (CVI)</p> Signup and view all the answers

    Study Notes

    Cardiovascular Disorders

    Atherosclerosis

    • Definition: Fibrous fatty lesions (plaques) that form in large and medium-sized arteries, reducing blood flow and causing ischemia to supplied organs/tissues
    • Principally a disease of the tunica intima of arteries
    • Results in:
      • Increased wall thickness and decreased elasticity
      • Reduced vessel radius and flow rate
      • Ischemia to supplied organs/tissues

    Etiology of Atherosclerosis

    • Related to endothelial cell damage
    • Causes:
      • Hyperlipidemia
      • Cigarette smoke
      • Diabetes
      • Immune mechanisms
      • Turbulent blood flow
    • Results in:
      • Increased endothelial permeability to plasma protein and lipids
      • Migration of monocytes and other leukocytes into sub-endothelial layers
      • Macrophages differentiate to lipid-filled foam cells
      • Growth of plaque lesions

    Coronary Artery Disease (CAD)

    • Cause of ischemic heart disease
    • Third leading cause of death in industrialized West
    • Nearly all elderly have some coronary impairment
    • Essential for healthcare professionals to understand pathophysiology

    Ischemic Heart Disease (IHD)

    • Disease characterized by ischemia (reduced blood supply) of the heart muscle
    • Usually due to coronary artery disease (atherosclerosis of the coronary arteries)
    • Coronary arteries:
      • Left (main) and right
      • Originate from the aorta
      • Main arteries on the surface, deeper branches penetrate the muscle
      • Right coronary artery supplies mostly the right ventricle and posterior regions of the heart
      • Left coronary artery supplies mostly the left ventricle and interventricular septum

    Myocardial Blood Flow

    • In strenuous exercise, coronary blood flow increases 3-4 times
    • Nervous control of myocardial blood flow operates by two mechanisms:
      • Autonomic control: parasympathetic via vagus nerve and sympathetic nervous systems
      • Local autoregulatory control: nitric oxide and adenosine
    • Myocardial blood flow is highest during diastole

    Angina Pectoris

    • Stable angina:
      • Chest pain caused by transient myocardial ischemia
      • Not severe enough to cause necrosis
      • Brought on by physical exertion or emotional stress
      • Myocardial blood flow cannot respond to increased demand due to narrowing of one or more coronary arteries by atherosclerotic plaque
    • Unstable angina:
      • The surface of a plaque experiences small disruptions, leading to the development of small thromboses
      • Causes periods of occlusion
      • Requires immediate hospitalization for rest, observation, and treatment

    Acute Coronary Syndrome (ACS)

    • Represents a spectrum of ischemic heart diseases, ranging from unstable angina to myocardial infarction
    • Pain persists longer than 20 minutes
    • May have a previous history of unstable angina as a risk factor
    • Symptoms not relieved by short-acting vasodilators

    Myocardial Infarction (MI)

    • Immediate result of complete coronary occlusion
    • Blood flow ceases in vessels beyond occlusion except for small amount of collateral flow
    • Produces acute ischemia in the myocardium supplied and varying degrees of ischemic injury and necrosis
    • Two important classifications:
      • STEMI (ST segment elevation on ECG)
      • Non-STEMI (sometimes thrombus disintegrates before complete tissue necrosis)

    Diagnostic Features of MI

    • Serum cardiac biomarkers (e.g., troponin T)
    • ECG changes (STEMI vs. non-STEMI)

    Management of Acute Coronary Syndrome

    • Immediate care:
      • Nitroglycerin (GTN)
      • Bed rest
      • Pain relief (morphine)
      • 12-lead ECG and ECG monitoring
      • Oxygen therapy
      • Beta blockers (slow HR, lengthen diastole)
      • Anticoagulant therapy (e.g., aspirin, platelet inhibitors)

    Causes of Death in Myocardial Infarction

    • Decreased cardiac output
    • Fibrillation of the heart
    • Rupture of the heart

    Electrocardiogram (ECG)

    • Electrical conduction within a normal heart
    • Normal ECG:
      • P wave: Atria depolarize
      • QRS complex: Ventricles depolarize
      • T wave: Ventricles recover from depolarization (repolarize)

    Disorders of the Heart

    • Pericarditis:
      • Acute inflammation of the pericardium
      • Pain, fever, and various causes
      • Treated by relieving symptoms and anti-inflammatory drugs
    • Cardiomyopathy:
      • Diverse group of diseases that primarily affect the myocardium
      • Many cases are idiopathic, some genetic, some acquired (e.g., result of inflammation)### Cardiomyopathies
    • Dilated cardiomyopathy:
      • Increased ventricular volume, causing impairment of systolic function
      • Causes: 1/3 inherited, infections, chemotherapy, or idiopathic
      • Typical clinical manifestations: dyspnea, orthopnea, reduced exercise capacity
      • Common cause of heart failure and transplantation
    • Hypertrophic cardiomyopathy:
      • Thickening of septum, decreasing left ventricular size and obstructing blood outflow
      • One of the most common types of cardiomyopathies, inherited
      • Mostly asymptomatic, but symptoms can include angina, dyspnea, reduced exercise capacity

    Valvular Dysfunction

    • Can be congenital or acquired
    • Most common acquired cause: rheumatic heart disease (after Streptococcus pyogenes infection)
    • Most commonly affects aortic and mitral valves
    • Two types of disruptions can occur:
      • Stenosis: narrowing of valve opening, causing turbulent flow and enlargement of emptying chamber
      • Incompetent (regurgitant) valve: permitting backward flow
      • Sounds made by abnormal flow = "murmurs"

    Heart Failure (HF)

    • Heart is unable to generate an adequate cardiac output (stroke volume x heart rate)
    • Stroke volume depends on preload, afterload, and myocardial contractility
    • HF may cause inadequate perfusion of tissues or increased pulmonary capillary pressures
    • Common causes: coronary artery disease, valvular disease, and cardiomyopathies
    • Most common reason for hospital admission in people over 65 years old

    Risk Factors for Heart Failure

    • Ischemic heart disease
    • Older age
    • Hypertension
    • Diabetes mellitus type 2
    • Lack of exercise
    • Smoking
    • Obesity

    Terms Affecting Stroke Volume

    • Preload:
      • Volume of blood in the ventricle at the end of diastole
      • Determined by amount of blood entering ventricle during diastole, blood left in ventricle after systole, and Frank-Starling law of the heart
    • Afterload:
      • Resistance to ejection of blood from the left ventricle
      • Peripheral vascular resistance is usually a good indicator of afterload
    • Inotropy (contractility):
      • Contractility of muscle
      • Ability of actin and myosin to interact and shorten against a load
      • Increases cardiac output, independent of preload and afterload

    Systolic and Diastolic Heart Failure

    • Systolic heart failure:
      • Myocardial contractility is impaired, leading to decreased ejection fraction
      • Causes: decreased contractility, volume overload, or pressure overload
      • More blood remains in the ventricle after contraction, leading to pulmonary or peripheral edema
    • Diastolic heart failure:
      • Decreased diastolic relaxation, leading to decreased cardiac output
      • Causes: conditions that decrease expansion of the ventricle, increase wall thickness, or delay diastolic relaxation

    Left and Right Heart Failure

    • Left heart failure (LHF):
      • Decreased cardiac output to systemic circulation
      • Can be systolic, diastolic, or both
      • Decreased cardiac output to systemic circulation leads to increased pulmonary venous pressure
      • Most common causes: hypertension, acute MI, cardiomyopathy
    • Right heart failure (RHF):
      • Inability of right ventricle to move deoxygenated blood from systemic circulation into pulmonary circulation
      • Pressure rises in systemic venous circulation, leading to peripheral edema
      • Causes: left heart failure, cor pulmonale, or right heart issues

    Compensatory Mechanisms in Heart Failure

    • Sympathetic nervous system activation:
      • Increases blood pressure and cardiac output
      • However, increases heart rate and contractility, putting more strain on the heart
    • Renin-angiotensin-aldosterone system (RAAS) activation:
      • Vasoconstriction increases afterload, and increased blood volume increases preload, both of which put more strain on the heart
    • Hypertrophy:
      • Varying degrees of ventricular wall thickening or thinning, leading to increased ischemia or dilation and impairment of contraction

    Circulatory Failure: Shock

    • Acute failure of the circulatory system to supply the body with an adequate blood supply, resulting in cellular hypoxia
    • Many causes and clinical manifestations
    • Ultimately leads to organ failure and death unless corrected

    Types of Shock

    • Cardiogenic shock:

      • Decreased cardiac output due to decreased contractility, increased preload, and/or increased afterload
      • Decrease in blood pressure causes compensation: increase in epinephrine release and RAAS system

    • Hypovolemic shock:

      • Not enough blood volume
      • Causes: significant loss of whole blood, plasma, or interstitial fluid
      • Begins to develop when intravascular volume has decreased by about 20%

    • Distributive shock:

      • Result of massive vasodilation
      • Blood volume has not changed, but the amount of space containing the blood has increased
      • Three shock states share this mechanism: neurogenic, anaphylactic, and septic

    • Obstructive shock:

      • Results from mechanical obstruction of blood flow through the central circulation (great veins, heart, or lungs)
      • Elevated right heart pressure occurs
      • Significant decrease in cardiac output
      • Often classified under cardiogenic shock### Primary Hypertension

    • Most cases (95%) are due to a combination of genetics and environmental factors.

    • Factors that can lead to primary hypertension include family history, age, gender, race, high dietary sodium intake, insulin resistance, cigarette smoking, and obesity.

    • Determined by several BP measurements at different times and tests to exclude secondary hypertension, including complete blood count (CBC), urinalysis, blood chemistry, ECG, and assessing target-organ damage.

    Pathophysiology of Hypertension

    • Increased blood pressure is due to an increase in circulating blood volume, increased peripheral resistance, or both.
    • Interaction of several factors, including:
      • Sympathetic nervous system, which increases heart rate and vasoconstriction.
      • Overactivity of the renin-angiotensin-aldosterone system (RAAS), which increases vasoconstriction and blood volume and pressure by retaining sodium and water in the kidneys.
      • Chronic inflammation, which results in smooth muscle contraction.

    Clinical Manifestations of Hypertension

    • Early stages have no symptoms or signs, other than elevated blood pressure (also known as a "silent disease").
    • Some people may never develop signs, symptoms, or complications, while others may become severely ill and die.
    • Clinical manifestations become evident when damage to other organs/systems occurs, and are specific to the affected organ/system, including:
      • Coronary heart disease
      • Kidney disease
      • CNS dysfunction (stroke, dementia)
      • Impaired vision

    Treatment of Hypertension

    • Includes lifestyle modification:
      • Exercise
      • Weight loss
      • Stop smoking and alcohol use
    • Medications:
      • Diuretics and other anti-hypertensives, e.g., ACE inhibitors

    Hypertension during Pregnancy

    • Can be classified as:
      • Pre-existing: present before pregnancy or appears before 20 weeks of pregnancy
      • Gestational: occurs at or after 20 weeks of pregnancy
    • Possibly due to a decrease in placental blood flow, leading to release of toxic compounds that cause changes in blood vessel walls throughout the body.

    Preeclampsia

    • Diagnosed if a woman presents with:
      • Hypertension (either gestational or pre-existing)
      • Proteinuria
      • Adverse conditions, e.g., persistent or new headache, visual disturbances, persistent abdominal pain, elevated liver enzymes, etc.
    • Can lead to eclampsia, which is the occurrence of convulsions and possible coma, due to development of blood clots in cerebral vessels.
    • Decrease in placental blood flow in gestational hypertension also affects the fetus, frequently resulting in infants who are small for gestational age and requiring early delivery.

    Diseases of the Arteries

    • Orthostatic (Postural) Hypotension:
      • Specific decrease in blood pressure within 3 minutes of moving to a standing position, causing dizziness, fainting
      • More frequently observed in the elderly
      • Normal mechanisms to maintain BP when standing up do not function, e.g., due to use of certain medications (e.g., antihypertensives), ageing, dehydration
    • Aneurysm:
      • Local outpouching of vessel or heart chamber wall, usually in the abdominal aorta
      • Most commonly caused by atherosclerosis and hypertension
      • Manifestations depend upon where the aneurysm is, and involve the production of pressure on local structures
    • Thrombus:
      • Caused by any condition that promotes activation of coagulation (surgery, infection, low BP, inflammation, etc.)
      • Can occlude the artery/vein or break off to form an embolus
    • Embolism:
      • Obstruction of a vessel by an embolus (air bubble, fat, dislodged thrombus, clump of cells)
      • No matter how tiny, it will eventually lodge in a vessel
      • Arterial emboli arise from the left heart and are associated with thrombi that occur after heart trauma (e.g., heart attack)
      • Pulmonary emboli arise from the venous side (e.g., DVT or in the right heart)

    Diseases of the Veins

    • Varicose Veins:

      • Definition: Veins in which blood has pooled, producing distended, tortuous, and palpable vessels
      • Why do they occur in the legs?:
        • There are no valves in the inferior vena cava or the common iliac veins, making the veins in the legs responsible for supporting the blood in these vessels
        • If pressure increases in the abdomen (pregnancy, repeated heavy lifting) this increases the strain on these valves
        • Standing for long periods of time also puts extra strain on these valves, as the leg muscles are not being used to pump blood back to the heart

    • Development of Varicose Veins:

      • If a valve in a vein is damaged, a section of the vein is subjected to the pressure of a larger volume of blood under the influence of gravity
      • The vein swells and edema develops in the surrounding tissue
      • This can damage the remaining upstream valves in the vein, making them unable to maintain normal venous pressure

    • Risk factors for Varicose Veins:

      • Standing long periods, crossing legs at the knee, age, female gender, family history, obesity, pregnancy, deep venous thrombosis, and previous leg injury

    • Treatment for Varicose Veins:

      • Wearing compression stockings, physical exercise, surgical ligation, vein stripping

    • Possible complication of Varicose Veins:

      • Chronic Venous Insufficiency (CVI), which is inadequate venous return over a long period of time, impairing blood flow to the area, especially in obese individuals.

    • Deep Venous Thrombosis (DVT):

      • Development of a thrombus in a deep vein, occurring primarily in the lower extremity
      • Risk factors include:
        • Venous stasis, due to immobility, allowing pooling of clotting factors (e.g., after hip fracture, joint replacement, spinal cord injury)
        • Impaired cardiac function (e.g., acute myocardial infarction, congestive heart failure)
        • Venous endothelial damage (e.g., intravenous drug use/groin injection)
        • Hypercoagulable states (e.g., inherited disorders, pregnancy)
      • Development of DVT:
        • Clotting factors and platelets accumulate (often near a valve) and form a thrombus
        • Inflammation around the thrombus promotes further platelet aggregation and the thrombus grows
        • Because the vein is deep in the leg, it is usually asymptomatic (may get edema if vessel is obstructed significantly)

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