Alterations In Cardiac Function: Part I

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Alterations In Cardiac Function Part I

• Pathophysiology
• N280
• Fall 2004

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Diseases of arteries and veinsSection C
Objective 1

• Arteriosclerosis
• Characteristics
• Abnormal thickening and hardening of vessel walls
• Narrowing of arterial lumen
• Associated with
• High blood pressure
• Insufficient perfusion of tissues
• Weakening and out-pouching of arterial walls

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Diseases of the arteries and veinsSection C
Objective 1

• Atherosclerosis
• Pathophysiology
• Inflammation from injury to endothelial cells
  that line the artery walls
• Macrophages move in to clean up and adhere to
  injured endothelial cells, releasing enzymes and
  toxic oxygen radicals further injuring cell wall
• Smooth muscle cells proliferate and migrate over
  fatty streak produced by macrophages, this forms
  a fibrous plague narrowing the lumen of the
  vessel
• Inflammation continues with platelet adherence to
  the plague making it unstable, causing a
  complicated lesion that may initiate the
  coagulation cascade resulting in thrombus
  formation with complete vessel occlusion

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Diseases of the arteries and veinsSection C
Objective 1

• Clinical manifestations
• Result from inadequate perfusion of tissues
• Transient ischemic events with stress or exercise
• Coronary artery disease (CAD) causing myocardial
  ischemia
• Stroke
• Evaluation and treatment
• Complete health history, PE, labs, other tests
• Goal of treatment to restore adequate blood
  flow
• If not emergent exercise, smoking cessation, and
  control of hypertension and diabetes, diet or
  meds to reduce LDL cholesterol if applicable

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Diseases of arteries and veinsSection C
objective 1
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Diseases of the arteries and veinsSection C
Objective 1

• Hypertension
• Consistent elevation of systemic arterial blood
  pressure
• Causes 1 in 8 deaths worldwide (third leading
  cause of death in the world)
• Stages of hypertension Pg 646, table 23-1
• All stages of HTN increase risk of cardiovascular
  disease events
• Caused by increases in cardiac output, total
  peripheral resistance, or both
• Primary or secondary hypertension

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Diseases of the arteries and veinsSection C
Objective 1

• Primary hypertension
• Pathophysiology
• 1. overactivity of the sympathetic nervous
  system
• 2. overactivity of the renin/angiotensin/aldoster
  one system
• 3. salt and water retention by the kidneys
• 4. hormonal inhibition of sodium-potassium
  transport across cell walls in the kidneys and
  blood vessels
• 5. a complex interaction involving insulin
  resistance and endothelial function
• Chronic hypertension damages the walls of the
  systemic blood vessels

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Diseases of the arteries and veinsSection C
Objective 1
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Diseases of the arteries and veinsSection C
Objective 1

• Secondary hypertension
• Caused by a systemic disease process
• Renal vascular disease, adrenal tumors, drugs
• If cause removed before permanent structural
  changes occur, blood pressure returns to normal
• Isolated systolic hypertension
• Systolic BP is gt140 mm Hg and diastolic is below
  90 mm Hg
• Strongly associated with cerebrovascular and
  cardiovascular events

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Diseases of the arteries and veinsSection C
Objective 1

• Complicated hypertension
• Sustained primary hypertension that has
  pathologic effects, compromises the structure and
  function of vessels themselves
• Ischemic and edema causing tissue damage
• Malignant hypertension
• Rapidly progressive HTN that can cause
  encephalopathy
• High arterial pressure renders the cerebral
  arterioles incapable of regulating blood flow to
  the cerebral capillary beds

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Diseases of the arteries and veinsSection C
Objective 1

• Clinical manifestations
• Early stages have no other clinical
  manifestations
• a silent disease
• Complications that damage organs and tissues
• Evaluation and treatment
• BP measurements, labs, electrocardiogram
• Diet, exercise, lifestyle cessations (smoking,
  alcohol), and medications (beta-blockers, ACE
  inhibitors, Ang II receptor blockers, clacium
  channel blockers)

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Diseases of the arteries and veinsSection C
Objective 1

• Postural or orthostatic hypotension
• Decrease in both systolic and diastolic arterial
  blood pressure on standing
• When a normal individual stands up, compensatory
  mechanisms kick inin orthostatic hypotension
  such compensatory mechanisms are slow or
  non-reacting
• Dizziness, blurring or loss of vision, syncope or
  fainting
• Significant risk factor for falls or injury

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Diseases of the arteries and veinsSection C
Objective 1

• Embolism
• The obstruction of a vessel by an embolus
• Embolus bolus of matter circulating in the
  bloodstream
• Thrombus, air bubble, amniotic fluid, fat,
  bacteria, cancer cells or a foreign substance
• Causes ischemia or infarction in tissues distal
  to the obstruction
• May cause myocardial infarction or stroke

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Disease of the arteries and veinsSection C
Objective 1

• Thrombus formation
• A blood clot that remains attached to a vessel
  wall. Thromboembolus a detached thrombus
• Tend to develop wherever intravascular conditions
  promote activation of the coagulation or clotting
  cascade
• Arterial thrombi may grow large enough to occlude
  the artery causing ischemia
• Treatment involves administration of heparin,
  coumadin, thrombolytics and surgical intervention

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Diseases of the arteries and veinsSection C
Objective 1

• Raynaud phenomenon and disease
• Phenomenon is secondary to systemic diseases
  (pulmonary hypertension, collagen vascular
  disease, thoracic outlet syndrome, myxedema
  trauma, serum sickness and long exposure to bad
  environmental conditions)
• Raynaud disease is primary vasospastic disorder
  of unknown origin. Attacks are triggered by
  brief exposures to cold conditions or emotional
  stress. May have genetic disposition

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Diseases of the arteries and veinsSection C
Objective 1

• Clinical manifestations
• Changes in skin color and sensation,
  pain/numbness with exposure to cold
• Attacks tend to be bilateral
• Treatment
• Removing stimulus or treating primary disease
• SSRIs
• Cigarette smoking cessation
• Calcium blockers may decrease vasospasm

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Diseases of the arteries and veinsSection C
Objective 1

• Varicose veins
• A vein in which blood has pooled, producing
  distended, tortuous, and palpable vessels
• Causes 1. trauma to the saphenous veins that
  damages one or more valves 2. gradual venous
  distention caused by a combination of standing
  for long periods, and the pull of gravity on
  blood
• Hydrostatic pressure increases, further
  distending the vein and making it tortuous edema
  then develops in the extremity

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Section C Objective 2

• Coronary artery disease, myocardial ischemia and
  myocardial infarction form a pathophysiologic
  continuum that impairs the pumping ability of the
  heart by depriving it of oxygen and nutrients
• Coronary artery disease (CAD)
• Any vascular disorder that narrows or occludes
  the coronary arteries
• Atherosclerosis is the most common cause

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Section C Objective 2

• In the U.S., CAD causes more than 500,000 MIs
  per year, causing one third of all deaths in the
  U.S.
• Risk factors hyperlipidemia, HTN, cigarette
  smoking, DM, obesity, genetic predisposition,
  sedentary life-style, estrogen deficiency, heavy
  alcohol consumption, gender, personality,
  hyperhomocystinemia, unknown

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Section C Objective 2

• Myocardial ischemia
• Pathophysiology
• Narrowing of a coronary artery by more than 50
• Atherosclerosis is most common cause
• Imbalance in supply and demand
• Hemodynamic factors
• Cardiac factors
• Hematologic factors
• Systemic disorders
• Increased demand

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Section C Objective 2

• Clinical manifestations
• Stable angina (predictable chest pain)
• Unpredictable chest pain (Prinzmetal angina)
• No symptoms (silent ischemia)
• Stable angina
• Angina pectoris is chest pain caused by
  myocardial ischemia
• Transient, lasting 3-5 minutes, may radiate to
  neck, lower jaw, left arm and left shoulder
• Commonly mistaken for indigestion
• Caused by gradual luminal narrowing and hardening
  of the arterial walls so that affected vessels
  cannot dilate in response to increased myocardial
  demand associated with physical exertion or
  emotional stress
• Pain relieved by rest and nitrates

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Section C Objective 2

• Prinzmetal angina is chest pain attributable to
  transient ischemia of the myocardium that occurs
  unpredictably and almost exclusively at rest
• Often occurs at night during rapid-eye-movement
  sleep
• May result from hyperactivity of the sympathetic
  nervous system, calcium influx into smooth
  muscle, or impaired production of prostaglandin
• Silent ischemia and mental stress-induced
  ischemia
• Stress management has been associated with a
  significant reduction in CAD events in men

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Section C Objective 2
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Section C Objective 2

• Evaluation and treatment
• PE (extra heart sounds), labs (hyperlipidemia and
  hypercholesterolemia)
• Electrocardiography (ECG)
• Dietary changes, lifestyle changes, environmental
  changes, drug therapy, antiplatelet agents,
  surgical interventions
• Unstable angina
• Indicates advancing ischemic heart disease
• Is seldom predictable
• Attacks often occur at rest, increasing in
  intensity and duration
• May be a manifestation of impending infarction

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Section C Objective 2

• Myocardial infarction
• When coronary blood flow is interrupted for an
  extended period of time resulting in necrosis
• Pathophysiology
• Cellular injury cardiac cells can withstand
  ischemic conditions for about 20 minutes before
  cell death occurs
• Cellular death irreversible hypoxic injury and
  tissue necrosis
• Oxygen deprivation and electrolyte disturbances
  affect pumping ability of the heart muscle
  leading to alterations in structure and function

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Section C Objective 2

• Clinical manifestations
• Sudden, severe chest pain that may radiate to the
  neck, jaw, back, shoulder, or left arm
• Nausea and vomiting
• Diaphoresis, cool and clammy skin, fever
• Labs rise in plasma enzymes (CK, LDH, AST)
• Evaluation and treatment
• History, PE, ECG, serial enzyme alterations,
  ultrasound imaging
• Oxygen, aspirin, pain relief, continuous
  monitoring
• Education on diet, exercise, caffeine, smoking
  cessation, and other risk factors