Cardiovascular System Assessment and Key Terms

Assessment of the Cardiovascular System

  • Key Terms:
      - Afterload: Pressure/resistance the ventricles must overcome to eject blood into peripheral blood vessels.
      - Apical Impulse: Pulse located at the left 5th intercostal space in the midclavicular line (mitral area).
      - Baroreceptors: Sensory receptors in the arch of the aorta and internal carotid arteries that are stimulated when arterial walls are stretched by an increased blood pressure (BP).
      - Blood Pressure (BP): The force of blood exerted against the vessel walls.
      - Bruit: Swishing sound that may occur from turbulent blood flow in narrowed or atherosclerotic arteries.
      - Cardiac Catheterization: Most definitive but most invasive test in the diagnosis of heart disease. It involves passing a small catheter into the heart and injecting contrast medium.
      - Cardiac Index: Calculation of cardiac output (CO) requirements to account for differences in body size; determined by dividing the CO by the body surface area.
      - Cardiac Output (CO): Volume of blood ejected by the heart each minute.
      - Cholesterol: Serum lipid that includes high-density lipoproteins (HDL) and low-density lipoproteins (LDL).
      - Diastole: Phase of the cardiac cycle that consists of relaxation and filling of the atrial ventricles (2/3 of the cardiac cycle).
      - Diastolic BP: The amount of pressure/force against the arterial walls during the relaxation phase of the cardiac cycle.
      - Echocardiograph: Use of ultrasound waves to assess cardiac structure and mobility, particularly in valves.
      - Electrophysiologic Study (EPS): An invasive procedure where programmed electrical stimulation of the heart is used to evaluate dysrhythmias and conduction abnormalities.
      - Exercise EKG: A test that assesses cardiovascular response to an increased workload (also called a stress test).
      - Heart Rate (HR): Number of times the ventricles contract in one minute.
      - High-density Lipoprotein (HDL): "Good" cholesterol; males: greater than 45 mg/dL; females: greater than 55 mg/dL.
      - Highly Sensitive C-Reactive Protein (hsCRP): A serum marker of inflammation and a common critical component of the development of atherosclerosis.
      - Homocysteine: An amino acid that is produced when protein breaks down; elevated values may be a risk factor for the development of cardiovascular disease.
      - Low-density Lipoprotein (LDL): "Bad" cholesterol; should be less than 130 mg/dL.
      - Mean Arterial Pressure (MAP): Arterial BP that is necessary (between 60–100 mmHg) to maintain perfusion of major body organs: kidneys and brain.
      - Murmur: Abnormal heart sound that reflects turbulent blood flow through normal/abnormal valves.
      - Myocardium: The muscle tissue of the heart.
      - Orthostatic Hypotension: Decrease in BP that occurs within the first few seconds to minutes after changing from a sitting or lying position to a standing position.
      - Pack-Years: Number of packs per day times the number of years smoked (e.g., 1.5 pk/day for 20 years = 30 pack years).
      - Palpitations: Feeling of fluttering in the chest; irregular heartbeat.
      - Paradoxical BP: Exaggerated decrease in systolic pressure (10 mmHg) during the inspiratory phase of respiration.
      - Pleural Friction Rub: Abnormal sound originating from the pericardial sac, occurring with the movements of the cardiac cycle.
      - Preload: The degree of myocardial fiber stretch at the end of diastole and just before contraction.
      - Pulse Pressure: Systolic BP minus diastolic BP (PP=SystolicBP−DiastolicBPPP = Systolic BP - Diastolic BP).
      - Radionuclide Myocardial Perfusion Imaging (rMPI): Use of radionuclide techniques in cardiovascular assessment.
      - Stroke Volume (SV): Amount of blood ejected by the left ventricle during each contraction.
      - Systole: Phase of the cardiac cycle that consists of contraction and emptying of the atrial ventricles.
      - Systolic BP: Amount of pressure/force generated by the left ventricle to distribute blood into aorta with each contraction.
      - Transesophageal EKG (TEE): Form of EKG performed through the esophagus that examines function and structure of the heart.
      - Triglycerides: Serum lipid profile that includes measurement of cholesterol and lipoproteins.
      - Troponin: Myocardial muscle protein released into the bloodstream when there is injury to myocardial muscle.

Blood Flow and Cardiac Cycle

  • Blood Flow through the Heart:
      - Deoxygenated blood flows from the body through the superior/inferior vena cava to the right atrium.
      - Through the tricuspid valve to the right ventricle.
      - Through the pulmonic valve to the pulmonary arteries to the lungs.
      - Oxygenated blood returns to the left atrium via pulmonary veins.
      - Through the mitral valve to the left ventricle.
      - Through the aortic valve to the aorta and into the body.

  • Cardiac Cycle Phases:
      - Diastole:
        - Ventricular filling occurs (relaxation).
        - Approx 70% of blood flows passively into ventricles.
        - Atrial contraction pumps the last 30% into ventricles.
      - Systole:
        - Ventricle contraction where the ventricles pump out blood.
        - Each beat of the heart takes approximately 0.3 seconds to pump out SV (70 mL).
        - AV valves are closed while semilunar valves are open during this phase.

Preload, Afterload, and Mean Arterial Pressure (MAP)

  • Preload:
      - How much the heart muscle is stretched by blood filling the ventricles before contraction.
      - Analogy: Ventricle is like a balloon.
        - More filled = more stretch = higher preload.
        - Less filled = less stretch = lower preload.
      - Elevated Preload Indicators: Hypervolemia, heart failure, valve stenosis.
      - Decreased Preload Indicators: Hypovolemia, dehydration.

  • Afterload:
      - Pressure/resistance that the ventricles must overcome to eject blood through the semilunar valves into peripheral blood vessels.
      - Higher afterload results in the heart working harder and decreased stroke volume (SV).
      - Lower afterload allows the heart to pump more easily and improves SV.
      - Elevated Afterload Conditions: Hypertension, aortic stenosis.
      - Decreased Afterload Conditions: Sepsis, vasodilation.

  • Mean Arterial Pressure (MAP):
      - Calculated as follows:
        MAP=SystolicBP+2imesDiastolicBPMAP = Systolic BP + 2 imes Diastolic BP
      - Indicates perfusion of vital organs (kidney and brain) and must be at least 60 mmHg for adequate organ perfusion.
      - Normal MAP range is 60-100 mmHg.

Cardiovascular System Assessment

  • Peripheral Edema: Accumulation of fluid in legs and feet.

  • Patient History Assessment:
      - Location of edema can determine potential causes.
        - Bilateral Edema: Could indicate HF or chronic venous insufficiency.
        - Localized Edema: Could indicate thrombosis or lymphedema.

  • Risk Factors:
      - Nonmodifiable: Age, sex, ethnic origin, family history of cardiovascular disease (CVD), chronic conditions.
      - Modifiable: Smoking, physical inactivity, obesity, stress, diet/lipid levels.

  • Current Health Problems:
      - Assess for symptoms such as fatigue, shortness of breath (dyspnea), chest pain/discomfort, palpitations.
      - Pitting Edema graded based on depression:
        1. Mild (1+): disappears rapidly.
        2. Moderate (2+): disappears in 10-15 seconds.
        3. Moderate severe (3+): disappears after 1 minute.
        4. Severe (4+): disappears after 2 minutes.

Chest Discomfort Assessment

  • Characteristics to Assess:
      - Onset, quality/severity, location/radiation, duration/relieving factors.

  • Angina:
      - Sudden, squeezing, viselike pain typically on the left side of the chest; lasts less than 15 minutes.
      - Relieved with rest, nitrates, or oxygen therapy.

  • Myocardial Infarction (MI):
      - Intense, continuous pain often substernal; not relieved with rest.

  • Pericarditis:
      - Sudden sharp, stabbing pain, relieved by sitting upright.

  • Anxiety or Esophageal Causes: Symptoms may mimic those of angina or MI and should be assessed for severity.

Heart Sounds and Murmurs

  • Heart Sounds:
      - S1 (LUB): Closing of the AV valves, marks the beginning of ventricular systole.
      - S2 (DUB): Closing of the semilunar valves, marks the end of ventricular systole.
      - S3: Normal in youth, abnormal in adults over 40; indicates rapid ventricular filling.
      - S4: Always abnormal; indicates atrial contraction into stiff ventricles.

  • Heart Murmur Grading:
      - Grade I: Very faint.
      - Grade II: Faint but recognizably.
      - Grade III: Moderate intensity.
      - Grade IV: Loud, with palpable thrill.
      - Grade V: Very loud; hearable with stethoscope partially off the chest.
      - Grade VI: Very loud; audible without stethoscope.

Atherosclerosis and Laboratory Assessment

  • Atherosclerosis:
      - Narrowing of arteries due to plaque buildup leading to decreased blood flow, which can result in myocardial ischemia.
      - Plaque rupture can lead to thrombus formation blocking blood flow.

  • Laboratory Assessment Indicators:
      - Serum Lipids: Total cholesterol: < 200 mg/dL, LDL: < 130 mg/dL, HDL: > 40 mg/dL for males and > 50 mg/dL for females, Triglycerides: < 150 mg/dL.
      - Troponin: Indicative of myocardial injury; rise in levels indicates MI.
      - Prothrombin Time (PT): Measure of how long it takes blood to clot; normal is 10-14 seconds.

  • Additional Testing:
      - International Normalized Ratio (INR) for those on anticoagulants (normal: 0.8-1.2). Higher for patients with prosthetic heart valves (3.0–4.5).

Cardiac Catheterization

  • Cardiac Catheterization:
      - Involves threading a catheter through a blood vessel to the heart to assess coronary artery status.
      - Left Heart Catheterization: Enters through an artery; looks at coronary arteries and left-side heart pressures.
      - Right Heart Catheterization: Enters through a vein; measures pressures in the right atrium and ventricle, useful for pulmonary hypertension and heart failure.

  • Complications of Cardiac Catheterization:
      - Dysrhythmias, thrombophlebitis, arterial bleeding, hematoma, potential for cardiac tamponade, pulmonary embolism, infection at insertion site.

Cardiac Medications

  • Nitrates: Vasodilate coronary arteries
      - Nursing interventions include assessing BP (hold if SBP < 90) and monitoring chest pain relief.

  • Aspirin: Decreases platelet aggregation to prevent coronary thrombosis. Assess for bleeding.

  • ACE Inhibitors: Decrease afterload, monitor BP for hypotension.

  • Beta Blockers: Decrease oxygen demand, hold if HR < 60 bpm.

  • Calcium Channel Blockers: Assess HR and BP, may cause tachycardia or bradycardia.

Acute Coronary Syndromes (ACS)

  • Definition: Disorders including unstable angina and myocardial infarction (MI) due to obstruction of coronary arteries.

  • Angina Pectoris: Chest pain due to a temporary imbalance between oxygen supply and demand.

  • Myocardial Infarction (MI): Injury to myocardial tissue due to oxygen deprivation; atypical symptoms may include fatigue or indigestion in women.

Risk Factors for Cardiovascular Disease

  • Nonmodifiable Risk Factors: Age, sex, family history, ethnicity.

  • Modifiable Risk Factors: Smoking, hypertension, diabetes, physical inactivity, obesity.

Heart Failure (HF)

  • Definition: Chronic condition where the heart cannot pump enough blood to meet metabolic needs.

  • Types of Heart Failure: Left-sided (causes pulmonary congestion) and right-sided (causes systemic congestion).
      - Signs include dyspnea, orthopnea, edema, and fatigue.

  • Stages of Heart Failure:
      - Stage A: At risk without symptoms.
      - Stage B: Evidence of structural heart disease without symptoms.
      - Stage C: Current or previous symptoms of heart failure.
      - Stage D: Advanced heart failure with marked symptoms hindering daily life.

Valvular Disorders

  • Types:
      - Stenosis: Valve does not open completely; causes pressure overload.
      - Regurgitation: Valve does not close completely; causes volume overload.

  • Management: May include medications or surgical intervention such as valve repair or replacement.

Infective Endocarditis

  • Pathophysiology: Microbial infection of the endocardium; can be caused by staphylococcus or streptococcus.

  • Assessment: Features include fever, heart murmur, fatigue, and embolization signs.

Pericarditis and Cardiac Tamponade

  • Pericarditis: Inflammation of the pericardium leading to chest pain and pericardial friction rub.

  • Cardiac Tamponade: Accumulation of fluid in the pericardial cavity causing impeded heart filling; treated with pericardiocentesis or surgery.

Management Strategies

  • Post-MI Care: Assess for complications; medications to manage symptoms and prevent future events.

  • Patient Education: Promote adherence to medication regimes, lifestyle changes, and regular monitoring for potential signs of cardiac distress.

  • Challenges and Considerations: Individualize treatment based on each patient's risks, morphology of disease, and psychosocial factors.