Cardiology-Nursing

Anatomy of the Heart

  • Structure:

    • Hollow muscular organ

    • Weighs between 300-400 gms

    • Resembles a closed fist

    • Located between the lungs and diaphragm in the middle of the mediastinum

  • Influencing Factors:

    1. Age

    2. Gender

    3. Weight

    4. Extent of physical exercise

Layers of the Heart Wall

  • Epicardium:

    • Outer layer

    • Protective

  • Myocardium:

    • Middle layer

    • Muscular layer responsible for contraction and pumping function

  • Endocardium:

    • Inner layer

Pericardium

  • Structure:

    • Thin fibrous sheet encased by an invaginated sac

    • Comprises parietal and visceral layers

      • Parietal Pericardium: Outer layer

      • Visceral Pericardium: Inner layer

  • Pericardial Fluid:

    • Lubricates to reduce friction

    • Typically 10-20 ml; larger amounts can indicate pericardial effusion

  • Heart Chambers & Function:

    • Diastole: Relaxation phase allowing ventricles to fill

    • Systole: Contraction phase pumping blood out

    • Right Atrium & Right Ventricle: Receives venous blood and pumps to lungs for oxygenation

    • Left Atrium & Left Ventricle: Receives oxygenated blood and pumps to the body

Blood Flow Mechanisms

  • Pulmonary Artery:

    • Only artery that carries deoxygenated blood (away from the heart to the lungs)

  • Veins:

    • SVC: Collects blood from the head and neck

    • IVC: Collects blood from the trunk

    • Coronary Sinuses: Collects venous blood from heart muscle

  • Heart Valves:

    • Atrioventricular Valves: Tricuspid and Mitral valves separate atria from ventricles

    • Semilunar Valves: Pulmonic and Aortic valves provide access to systemic circulation

Heart Sounds

  • S1 (lub):

    • First heart sound, occurs with closure of AV valves during systole

  • S2 (dub):

    • Second heart sound, occurs with closure of semilunar valves during diastole

  • Additional Sounds:

    • S3 and S4 may indicate rapid ventricular filling or stiffened ventricles

Murmurs

  • Causes:

    1. Narrowed valves

    2. Malfunctioning valves

    3. Congenital heart defects

  • Pericardial Friction Rub: Sounds like scratching or the rubbing of sandpaper

Diagnostic Tests for Cardiac Assessment

  • Cardiac Biomarkers:

    • Trop: 7 days - 3 weeks

    • CKMB: indicative but less specific

    • Myoglobin: not cardiac-specific

  • Blood tests:

    1. Lipid Profile (Cholesterol, LDL, HDL, Triglycerides)

    2. BNP (Brain Natriuretic Peptide): elevated in congestive heart failure

    3. CRP (C-reactive Protein): can indicate inflammation

Stress Testing

  • Pharmacological Stress Testing:

    • Uses vasodilating agents (adenosine, dobutamine)

    • Useful for patients unable to perform physical stress tests

  • Cardiac Catheterization:

    • Best site via femoral, brachial, or radial arteries

    • Involves injecting dye for imaging

Hypertension and Its Management

  • Types:

    1. Primary Hypertension: Idiopathic with contributing factors like diet, alcohol

    2. Secondary Hypertension: Due to identifiable conditions like kidney disease

  • Medications:

    • ACE inhibitors, Angiotensin receptor blockers, Beta-blockers, Calcium channel blockers

    • Monitor side effects and contraindications

Angina Pectoris

  • Types of Angina:

    1. Stable: Predictable onset with exertion

    2. Unstable: Occurs suddenly, unpredictable

    3. Prinzmetal's: Caused by vasospasm

  • Management Goals:

    1. Provide relief

    2. Prevent further ischemia

    3. Educate on lifestyle changes

Myocardial Infarction (MI)

  • Types:

    1. Transmural: Affects full thickness of the myocardium

    2. Subendocardial: Affects only inner layers

  • Signs:

    • Chest pain, hypotension, diaphoresis, tachycardia

  • Management:

    • Cardiac enzymes, medications to relieve pain, prevent further clotting

Nursing Considerations for Pericarditis and Cardiac Tamponade

  • Pericarditis:

    • Symptoms include chest pain, fever, tachycardia

    • Treatment involves anti-inflammatory medications and possibly pericardiocentesis

  • Cardiac Tamponade:

    • Signs include Beck's Triad: JVD, muffled heart sounds, hypotension

    • Emergency intervention may be required to relieve pressure

Cardiomyopathies

  • Types:

    1. Dilated Cardiomyopathy (DCM): Enlarged chambers

    2. Hypertrophic Cardiomyopathy (HCM): Thickened muscle walls

  • Management:

    • Focus on heart failure management and potential heart transplant if necessary