Overview of the Cardiovascular System

Structure and Function

The cardiovascular system is responsible for transporting blood, nutrients, gases, and waste products throughout the body. It consists of the heart, blood vessels, and blood.

• Layers of the Heart Wall:

  • Pericardium: The outer protective sac surrounding the heart.

  • Myocardium: The muscular middle layer responsible for heart contractions.

  • Endocardium: The inner lining of the heart chambers and valves.

• Heart Chambers:

  • Four chambers: Right atrium, Right ventricle, Left atrium, Left ventricle.

  • Chambers are separated by valves to prevent backflow of blood.

• Great Vessels:

  • Major arteries and veins connected to the heart, including the ascending aorta, superior and inferior vena cava, and pulmonary veins.

• Blood Vessel Circulation:

  • Pulmonary circulation: Carries deoxygenated blood from the right ventricle to the lungs and returns oxygenated blood to the left atrium.

  • Systemic circulation: Delivers oxygenated blood from the left ventricle to the body and returns deoxygenated blood to the right atrium.

Cardiovascular System – Additional Terminology

Key Physiological Concepts

• Cardiac Output (CO): The volume of blood the heart pumps per minute. Formula: Where HR is heart rate and SV is stroke volume. Normal Range: 4–6 L/min in a resting adult.

• Preload: The amount of blood returning to the heart (venous return) that builds during diastole. Frank-Starling Law: The greater the stretch of the heart muscle, the stronger the contraction, resulting in increased stroke volume.

• Afterload: The pressure the ventricles must overcome to eject blood through the aortic valve. Clinical relevance: Increased afterload (e.g., due to hypertension) makes it harder for the heart to pump blood.

Anatomical and Pathophysiological Considerations

Infants and Children

Cardiovascular anatomy and physiology change significantly from birth through childhood.

• At birth, oxygenation shifts from placental to pulmonary (lung-based) circulation.

• By one year, the left ventricle's mass reaches the adult ratio of 2:1 compared to the right ventricle.

• Heart murmurs are common in childhood (approx. 30%) and often benign.

Older Adults – Haemodynamic Changes

Aging affects cardiovascular structure and function, often compounded by lifestyle and disease.

• Increased systolic blood pressure (BP): Due to thickening and stiffening of large arteries (arteriosclerosis).

• Increased left ventricular wall thickness.

• Diastolic BP may decrease after age 60.

• Reduced ability to augment cardiac output with exercise.

• No change in resting heart rate or cardiac output with aging.

• Higher risk of dysrhythmias and bundle branch block; ectopic beats are common but usually asymptomatic.

Cardiovascular Conditions – Older Adult

Common Disorders and Risk Factors

Cardiovascular disease (CVD) is prevalent in older adults and is a leading cause of morbidity and mortality.

• Coronary heart disease, stroke, and heart failure are the most common CVDs.

• Incidence of CVD increases sharply with age, accounting for approximately 89% of deaths in adults aged 65 and over.

• Underlying cause of 25% of all deaths in Australia (2021 data).

• Hypertension (HTN): BP ≥ 140/90 mmHg; incidence increases with age and can damage the heart and other organs.

• Congestive cardiac failure: Adults aged 75+ have a tenfold higher risk than younger adults.

• Peripheral arterial disease (PAD): Risk increases if underlying conditions (e.g., diabetes) are present.

• Atrial fibrillation (AF): A common arrhythmia; risk increases markedly with age.

• Physical activity reduces risk of death from CVD and respiratory illnesses.

Risk Factors Table

Cardiovascular Assessment

Subjective Data Collection

Subjective assessment involves gathering information from the patient about symptoms and history.

• Chest pain

• Dyspnoea (shortness of breath)

• Orthopnoea (difficulty breathing when lying flat)

• Cough

• Fatigue

• Cyanosis or pallor

• Oedema (swelling)

• Nocturia (nighttime urination)

• Personal and family cardiac history

• Patient-centered care: assessment of cardiac risk factors

Additional History: Infants, Children & Older Adult

Special considerations are needed for different age groups during cardiovascular assessment.

Preparation and Equipment for Cardiovascular Assessment

Preparation

• To evaluate carotid arteries, the patient can be sitting.

• To assess jugular veins and precordium, the patient should be supine with the chest slightly elevated.

• Ensure privacy, especially for female patients.

Equipment

• Marking pen

• Small centimeter ruler

• Stethoscope with diaphragm and bell endpieces

• Alcohol wipe to clean endpiece

• Perform hand hygiene before assessment

Assessment – Objective Data

Physical Examination Steps

• Inspection:

  • Inspect jugular venous pulse

  • Inspect anterior chest for pulsations

• Palpation:

  • Palpate one carotid artery at a time

  • Palpate apical pulse (location, size, amplitude, duration)

  • Palpate across precordium for pulsations

• Auscultation:

  • Auscultate apical pulse at the 5th intercostal space, midclavicular line

  • Use both diaphragm and bell of stethoscope

  • Note rate and rhythm; compare with radial pulse

Application of Anti-Embolic Stockings

Purpose and Procedure

Anti-embolic stockings are used to prevent venous thromboembolism (VTE) by promoting venous return in the lower limbs.

• Assess the patient's skin for fragility or recent skin grafts before application.

• Measure the limb to ensure correct sizing.

• Check for contraindications such as peripheral arterial disease or heart failure.

• Stockings should be worn for the prescribed duration, typically during periods of immobility.

Contraindications Table

References

• Lewis Medical Surgical Nursing: Assessment and Management of Clinical Problems

• Understanding Pathophysiology

• Fundamentals of Applied Pathophysiology

• Elsevier Inc. (2020)

Additional info: Expanded explanations and tables were added for completeness and clarity based on standard academic sources.