unit 2

NURS 1021 – UNIT 2 CARDIOVASCULAR DISORDERS PART 1 – ALTERATIONS IN BLOOD FLOW

Arteries

Function

  • Carry oxygenated blood away from the heart.

  • Operate as a high-pressure system that facilitates the distribution of blood throughout the body.

Structure

  • Composed of thick elastic walls, allowing ability to withstand high pressure.

  • Smooth muscle composition permits vasoconstriction (narrowing of the blood vessels) and vasodilation (widening of the blood vessels).

Clinical Importance

  • Importance of unobstructed arteries:

    • A blocked artery can lead to ischemia (insufficient blood supply) and subsequent tissue death.

Symptoms of Reduced Arterial Flow

  • Indicators of compromised blood flow include:

    • Pain

    • Cold limb

    • Weak or absent pulse

    • Pale skin

    • Numbness

The 6 P’s of Arterial Occlusion

  1. Pain

  2. Pallor (pale skin)

  3. Pulselessness (absence of pulse)

  4. Polar (cold limb)

  5. Paresthesia (tingling sensation)

  6. Paralysis

  • Considered a medical emergency given the rapid progression towards tissue damage if not addressed.

Major Pulse Points

  • Locations where pulse can be palpated include:

    • Temporal

    • Carotid

    • Brachial

    • Radial

    • Femoral

    • Popliteal

    • Posterior tibial

    • Dorsalis pedis

Veins

Function

  • Return deoxygenated blood back to the heart.

  • Operate as a low-pressure system.

Structure

  • Composed of thin walls.

  • Contain one-way valves which prevent backflow of blood.

Blood Flow Dependence Factors

  1. Presence of valves

  2. Calf muscle pump, aiding in the return of blood

  3. Respiratory pump, influenced by breathing

Venous Incompetence

  • Definition: Condition that occurs when vein valves fail to function correctly.

Causes

  • Factors contributing to venous incompetence include:

    • Aging

    • Long periods of standing

    • Obesity

    • Pregnancy

Symptoms

  • Clinical manifestations of venous incompetence might include:

    • Swelling (edema)

    • Warm limb

    • Skin discoloration

    • Varicose veins (enlarged superficial veins)

    • Venous ulcers (sores that occur due to poor circulation)

Complication

  • Potential complication of venous incompetence includes:

    • Deep Vein Thrombosis (DVT) - a blood clot that forms in a deep vein.

PART 2 – CORONARY HEART DISEASE

Coronary Heart Disease (CHD)

  • Definition: Reduced blood flow to heart muscle due to atherosclerosis (plaque build-up) in coronary arteries.

  • Also referred to as Ischemic Heart Disease.

Risk Factors
Non-Modifiable Factors

  • Factors that cannot be changed include:

    • Age

    • Male sex

    • Family history of heart disease

Modifiable Factors

  • Factors that can be controlled include:

    • Smoking

    • Hypertension (high blood pressure)

    • Diabetes

    • Obesity

    • High cholesterol levels

    • Sedentary lifestyle

Atherosclerosis

  • Definition: The accumulation of fatty plaque in the arteries.

Pathogenesis

  1. Initial endothelial injury (damage to the lining of blood vessels)

  2. LDL (low-density lipoproteins) enters vessel wall

  3. Macrophages ingest LDL, transforming into foam cells

  4. Formation of fatty streak in the arterial wall

  5. Smooth muscle cells form fibrous plaque, which narrows the artery and reduces blood flow

Complications of Atherosclerosis

  • Associated complications include:

    • Thrombosis (formation of a blood clot)

    • Embolism (blockage caused by a clot that has traveled)

    • Aneurysm (bulging of an artery wall)

Angina

  • Definition: Chest pain that occurs due to temporary myocardial ischemia (insufficient blood supply to the heart muscle).

Causes

  • Angina is often caused by narrowed coronary arteries.

Triggers

  • The 3 E’s that can trigger angina include:

    1. Exertion

    2. Emotion (stress)

    3. Eating

Symptoms

  • Symptoms typically consist of:

    • Chest pressure

    • Pain radiating to the arm, neck, and jaw

    • Nausea

    • Sweating

    • Anxiety

Relief

  • Angina is often relieved by:

    • Resting

    • Administration of nitroglycerin

Acute Coronary Syndrome (ACS)

  • Includes a spectrum of conditions comprising:

    1. Unstable angina

    2. Non-ST-segment elevation myocardial infarction (NSTEMI)

    3. ST-segment elevation myocardial infarction (STEMI)

Cause

  • Commonly attributed to plaque rupture and subsequent clot formation leading to reduced blood flow.

Myocardial Infarction (Heart Attack)

  • Definition: Death of heart muscle due to full blockage of a coronary artery.

Symptoms

  • Common symptoms include:

    • Severe chest pain

    • Shortness of breath

    • Sweating

    • Nausea

    • Anxiety

ECG Changes

  • Changes observed in ECG may include:

    • ST elevation (indicative of STEMI)

Sudden Cardiac Arrest

  • Definition: Unexpected cardiac death that occurs within 1 hour of symptoms onset.

Most Common Cause

  • Ventricular fibrillation (irregular heart rhythms that lead to cardiac arrest).

Cardiomyopathies

Dilated Cardiomyopathy

  • Definition: Condition where heart chambers enlarge and weaken.

Causes

  • Contributing factors may include:

    • Alcohol abuse

    • Viral infections

    • Genetic predispositions

Symptoms

  • Common symptoms include:

    • Heart failure

    • Arrhythmias (irregular heartbeats)

    • Risk of embolism (clot formation)

Hypertrophic Cardiomyopathy

  • Definition: Condition characterized by thickened heart muscle.

Symptoms

  • Symptoms often experienced include:

    • Shortness of breath

    • Chest pain

    • Syncope (fainting)

    • Arrhythmias

Major Risk

  • Particularly leads to sudden cardiac death in younger individuals.

Restrictive Cardiomyopathy

  • Definition: Characterized by stiffness of the heart muscle.

Effects

  • Impacts may include:

    • Poor ventricular filling

    • Symptoms associated with heart failure

Pericardial Disorders

Pericarditis

  • Definition: Inflammation of the pericardium (the heart’s outer layer).

Symptoms

  • Typical symptoms include:

    • Sharp chest pain that worsens with breathing

    • Relief obtained by leaning forward

    • Presence of pericardial friction rub on auscultation

Pericardial Effusion

  • Definition: Buildup of fluid surrounding the heart.

Symptoms

  • Symptoms may consist of:

    • Dyspnea (shortness of breath)

    • Distant heart sounds on examination

    • Increased Jugular venous pressure (JVP)

Cardiac Tamponade

  • Definition: A life-threatening condition which results in compression of the heart.

Causes

  • Often caused by rapid pericardial effusion.

Beck’s Triad (Important Exam Point)

  1. Hypotension (low blood pressure)

  2. Jugular venous distension (JVD)

  3. Muffled heart sounds upon auscultation

PART 3 – SHOCK

Shock

  • Definition: A life-threatening condition characterized by the inadequate delivery of oxygenated blood to tissues.

Main Problem

  • Primary issue is tissue hypoperfusion (decreased blood flow to tissues).

Types of Shock

  1. Cardiogenic Shock

    • Cause: Severe heart pump failure, commonly post-myocardial infarction (heart attack).

    • Pathophysiology: Heart's inability to pump leads to decreased cardiac output and resultant tissue hypoxia.

    • Symptoms:

      • Hypotension (low blood pressure)

      • Pulmonary edema (fluid in the lungs)

      • Cold clammy skin

      • Tachycardia (increased heart rate)

  2. Hypovolemic Shock

    • Cause: Caused by loss of blood volume or fluids.

    • Examples include:

      • Hemorrhage (loss of blood)

      • Burns

      • Severe dehydration

    • Pathophysiology: Low blood volume results in decreased preload (initial stretching of the cardiac muscle) and reduced cardiac output.

    • Symptoms:

      • Tachycardia

      • Low blood pressure

      • Cold clammy skin

      • Low urine output

  3. Distributive (Septic) Shock

    • Cause: Caused by severe infection leading to systemic infection response.

    • Mechanism: Characterized by extensive vasodilation, which results in a drop in blood pressure.

    • Symptoms:

      • Warm skin initially (due to vasodilation)

      • Hypotension

      • Tachycardia

      • Confusion or altered mental status

Stages of Shock

  1. Compensatory Stage

    • Body attempts to maintain blood pressure (BP).

  2. Progressive Stage

    • Characterized by hypotension, tissue hypoxia, and lactic acidosis.

  3. Refractory Stage

    • Final stage associated with organ failure and high likelihood of death.

Heart Failure

  • Definition: Insufficient pumping ability of the heart to meet the body's needs for blood.

Common Causes

  • Major causes include:

    • Coronary artery disease (CAD)

    • Hypertension

    • Cardiomyopathy

Systolic Heart Failure

  • Problem: Defined by weak contraction of the heart muscle.

  • Reduced ejection fraction (the percentage of blood pumped out of the heart with each beat) is commonly observed.

  • Cause: Often due to myocardial infarction (heart attack).

Symptoms of Heart Failure
Left-sided Heart Failure

  • Symptoms might include:

    • Pulmonary edema (fluid accumulation in the lungs)

    • Dyspnea (shortness of breath)

    • Orthopnea (difficulty breathing while lying flat)

    • Crackles heard in the lungs upon auscultation

Right-sided Heart Failure

  • Symptoms may include:

    • Peripheral edema (swelling in the limbs)

    • JVD (Jugular venous distension)

    • Hepatomegaly (enlargement of the liver)

    • Ascites (fluid accumulation in the abdominal cavity)

Stroke Volume and Cardiac Output

  • Stroke Volume (SV) is calculated as:
    SV=EDV−ESVSV = EDV - ESV
    where EDV is End Diastolic Volume and ESV is End Systolic Volume.

  • Cardiac Output (CO) is defined as:
    CO=HR×SVCO = HR × SV
    where HR is Heart Rate.

  • Blood Pressure (BP) is expressed as:
    BP=CO×TPRBP = CO × TPR
    where TPR is Total Peripheral Resistance.