Chapter 20 Notes

Chapter 20: Heart and Neck Vessels

POSITION AND SURFACE LANDMARKS

• Cardiovascular System: Composed of the heart (muscular pump) and blood vessels.

• Precordium: Area on the anterior chest overlying the heart and great vessels.

• Great Vessels: Major arteries and veins connected to the heart.

• Location of Heart and Great Vessels: Situated between the lungs in the mediastinum (middle third of the thoracic cage).

• Heart Structure:

  • Extends from the 2nd to the 5th intercostal space and from the right border of the sternum to the left midclavicular line.

  • Anterior rotation with the right side forward and the left side posterior.

  • Right Ventricle: Located behind the sternum; forms most of the anterior cardiac surface.

  • Left Ventricle: Lies behind the right ventricle; forms the apex and slender area of the left border.

  • Atria: Right atrium above the right ventricle; left atrium is posterior with the left atrial appendage visible anteriorly.

BLOOD CIRCULATION

• Blood vessels arranged in two loops: pulmonary and systemic circulation; the heart pumps blood into both simultaneously.

• Orientation of Heart: The "top" is the broader base, and the "bottom" is the apex.

• Apical Impulse: Apex beats against the chest wall during contraction.

• Great Vessels Anatomy:

  • Superior/Inferior Vena Cava: Return unoxygenated blood to the right heart.

  • Pulmonary Artery: Carries venous blood to lungs; bifurcates after leaving the right ventricle.

  • Pulmonary Veins: Return oxygenated blood to the left side of the heart.

  • Aorta: Carries blood from the left ventricle to the body; ascends from the left ventricle and arches at the sternal angle.

HEART WALL, CHAMBERS, AND VALVES

• Pericardium: Tough, fibrous, double-walled sac surrounding the heart with serous fluid that reduces friction.

• Myocardium: Muscular wall responsible for the heart's pumping action.

• Endocardium: Thin, endothelial lining of heart chambers and valves.

• Heart Function:

  • Right side pumps to lungs; left side pumps to the body.

  • Each side has an atrium (thin-walled reservoir) and a ventricle (thick-walled pumping chamber).

  • Valves: Prevent backflow of blood, opening and closing in response to pressure gradients.

    • Atrioventricular (AV) Valves:

      • Right AV valve (Tricuspid) separates the right atrium from the right ventricle.

      • Left AV valve (Bicuspid or Mitral) separates the left atrium from the left ventricle.

      • Open during diastole for ventricular filling; close during systole to prevent regurgitation.

    • Semilunar (SL) Valves:

      • Three cusps shaped like half moons (Pulmonic valve on right; Aortic valve on left).

    • Open during systole to allow blood to exit the ventricles.

• Important Note: No valves exist between the vena cava and right atrium or between pulmonary veins and left atrium.

• Consequences of high pressure in either side of the heart can lead to clinical manifestations, like distended neck veins or pulmonary congestion.

Page 2: DIRECTION OF BLOOD FLOW

• Pathway Overview:

  • From liver to Right Atrium (RA) via the Inferior Vena Cava.

  • Superior Vena Cava drains blood from the head and upper extremities into RA.

  • Blood moves from RA through Tricuspid Valve to Right Ventricle (RV).

• Blood moves from RV through Pulmonic Valve to Pulmonary Artery (delivering deoxygenated blood to the lungs).

• Oxygenated blood returns to Left Atrium (LA) through Pulmonary Veins.

• Blood flows from LA through Mitral Valve to Left Ventricle (LV).

• LV ejects blood through Aortic Valve into the Aorta, supplying oxygenated blood to the body.

• Circulation Dynamics: Blood moves along pressure gradients, flowing from high to low pressure.

CARDIAC CYCLE

• Phases:

  • Diastole: Ventricles relax and fill with blood (2/3 of cycle).

    • AV valves open; passive filling occurs due to higher atrial pressure.

    • Atrial contraction completes ventricular filling (presystole).

  • Systole: Heart contracts, pumping blood into pulmonary and systemic arteries (1/3 of cycle).

    • Ventricular pressure rises above atrial pressure, leading to AV valve closure.

    • Brief closure of all valves during isometric contraction increases ventricular pressure until aortic valve opens for blood ejection.

  • Back to diastole: All valves close, ventricles relax and fill again until the process repeats.

HEART SOUNDS

• Normal Sounds:

  • S1 (first heart sound): Closure of AV valves, beginning of systole (loudest at apex).

  • S2 (second heart sound): Closure of semilunar valves, end of systole (loudest at base).

  • Respiratory influences can affect timing and intensity of sound.

Page 3: EXTRA SOUNDS AND MURMURS

• Extra Heart Sounds:

  • S3: Early diastole; resistance to filling during rapid filling phase (indicative of certain heart conditions).

  • S4: End of diastole; resistance to filling in a non-compliant ventricle, occurs just before S1.

• Murmurs: Caused by turbulent blood flow, create a blowing or swooshing sound.

  • May indicate underlying pathological conditions (valvular stenosis, regurgitation, etc.).

  • Murmurs are characterized by:

    • Timing: Systolic or diastolic.

    • Frequency: High, medium, or low-pitched.

    • Duration: Short for heart sounds, longer silent periods.

Page 4: THE NECK VESSELS

• Carotid Artery Pulse:

  • Important central artery; timing coincides with ventricular systole.

  • Palpation assesses contour, amplitude and symmetry; normally smooth with brisk upstroke.

• Jugular Venous Pulse:

  • Provides information about the right side of the heart and reflects filling pressures; can be used to assess central venous pressure (CVP).

  • Distention of the jugular veins can suggest heart failure.

AGING AND HEMODYNAMIC CHANGES

• Age-related increase in systolic BP, termed isolated systolic hypertension; results from vascular stiffening.

• Heart size remains constant, but left ventricular wall thickens to handle increased workload.

• Resting heart rate and cardiac output remain unchanged; decreased ability to augment output during exercise.

• Increased incidence of dysrhythmias with age; prolonged PR and QT intervals observed on ECG.

• CVD incidence rises, being the leading cause of death in older adults.

Page 5: SYMPTOMS AND OBJECTIVE DATA

• Symptoms:

  • Orthopnea: Difficulty breathing when supine.

  • Cyanosis/Pallor: Results from MI or low output.

  • Edema: Dependent edema may occur in heart failure.

  • Nocturia: Increased urination due to fluid resorption.

EXAMINATION OF NECK VESSELS

• Palpation of Carotid Artery: Avoid excessive pressure; assess amplitude and contour bilaterally.

• Auscultation: Detects bruits; characterized by blowing sounds indicating turbulence.

  • Use bell of stethoscope at several points along the carotid artery, ensuring light contact to avoid artificial sounds.

• Jugular Vein Inspection: Assess CVP and intravascular volume. Higher positions signify elevated venous pressure.

Page 6: PHYSICAL EXAMINATION OF THE HEART

• Inspection of Anterior Chest: Look for visible apical impulse in the 4th or 5th intercostal space, at or medial to the midclavicular line.

• Palpation of Apical Impulse:

  • Helps locate the impulse precisely; normal size and duration noted.

• Auscultation: Focus on key valve areas rather than anatomical locations. Identify heaves or lifts indicating hypertrophy.

SOUND CHARACTERISTICS

• Rate and rhythm should be assessed; note regularity and any identified irregularities.

• Distinguish S1 and S2: S1 is louder at the apex, S2 at the base; they coincide with the carotid pulse.

Page 7: AUSCULTATION TECHNIQUE

• Valve areas to auscultate:

  • Aortic Valve Area: 2nd right interspace.

  • Pulmonic Valve Area: 2nd left interspace.

  • Tricuspid Valve Area: Left lower eternal border.

  • Mitral Valve Area: 5th interspace, left midclavicular line.

• Assess for rhythm irregularities such as tachydysrhythmias and check for pulse deficits; apical beat should correlate with radial pulse.

IDENTIFICATION OF HEART SOUNDS

• Identify unique characteristics of each sound; normal sounds vs. pathological deviations.

• Split S1 and S2: Conditions that indicate varied sounds during diaphragm or bell auscultation.

Page 8: EXAMINATION OF MURMURS

• Analyze murmur characteristics: Timing, loudness, pitch, pattern, quality, location, and radiation.

• Innocent vs. Functional Murmurs: Innocent murmurs indicate no disease; functional murmurs arise from increased blood flow in certain conditions.

• Murmurs should be described correctly to differentiate between pathologic and benign conditions.

Page 9: AGING AND MURMURS

• Aging leads to gradual rise in SBP with DBP remaining constant.

• Elderly patients may experience orthostatic hypotension and require careful examination of carotid arteries.

• Increased volume of the thorax with aging may complicate auscultation of heart sounds.

• Systolic murmurs are common; benign if occurring in the elderly, but further assessment may be necessary for abnormal sounds.