HA: Cardiovascular System

• Heart


  Hollow, muscular organ about the size of a closed fist, located between the lungs in the mediastinum, behind and to the left of the sternum
• Heart


  • Spans the area from the second to the fifth intercostal space
  • Right border aligns with the right border of the sternum
  • Left border aligns with the left midclavicular line
• Pericardium


  • Thin sac with an inner, or visceral, layer that forms the epicardium and an outer, or parietal, layer that protects the heart
  • Space between the two layers (the pericardial space) contains 10 to 20 ml of serous fluid, which lubricates and cushions the surface of the heart and prevents friction between the layers as the heart pumps
• Atria and ventricles


  • Heart has four chambers — two atria and two ventricles — separated by a cardiac septum
  • Upper atria have thin walls and serve as reservoirs for blood
  • Atria boost the amount of blood moving into the lower ventricles, which fill primarily by gravity
  • Left ventricle pumps blood against a much higher pressure than the right ventricle, so its wall is two and one-half times thicker
• Cardiac circulation


  1. Deoxygenated venous blood returns to the right atrium

  2. Blood in the right atrium empties into the right ventricle, which contracts

  3. Blood is ejected through the pulmonic valve into the pulmonary artery, then travels to the lungs to be oxygenated

  4. From the lungs, blood travels to the left atrium through the pulmonary veins

  5. The left atrium empties the blood into the left ventricle, which then pumps the blood with each contraction through the aortic valve into the aorta and throughout the body
• Valves


  • Keep blood flowing in only one direction through the heart
  • Healthy valves open and close passively as pressure changes within the four heart chambers
• Heart valves


  • Tricuspid valve (between right atrium and right ventricle)
  • Mitral valve (between left atrium and left ventricle)
  • Pulmonic valve (between right ventricle and pulmonary artery)
  • Aortic valve (between left ventricle and aorta)
• Valve leaflets/cusps


  • Anchored to the heart wall by cords of fibrous tissue called chordae tendineae, which are controlled by papillary muscles
  • Maintain tight closure
• Cardiac conduction system


  • Begins with the heart's pacemaker, the sinoatrial (SA) node
  • Impulse travels through the atria along Bachmann's bundle and the internodal pathways to the atrioventricular (AV) node and the ventricles
  • After passing through the AV node, impulse travels down the bundle of His, then along the bundle branches and Purkinje fibers
• Cardiac cycle


  Consists of systole (heart contracts and sends blood on its outward journey) and diastole (heart relaxes and fills with blood)
• Cardiac cycle


  1. Atrial systole (atria contract, emptying blood into ventricles)

  2. Ventricular systole (ventricles contract, ejecting blood from the heart)

  3. Diastole (atria and ventricles relax and blood refills each chamber)
• Arteries


  • Carry blood away from the heart
  • Nearly all arteries carry oxygen-rich blood from the heart throughout the rest of the body
  • Thick-walled because they transport blood under high pressure
• Capillaries


  • Exchange of fluid, nutrients, and metabolic wastes between blood and cells occurs here
  • Thin-walled and highly permeable
  • Arterioles constrict and dilate to control blood flow
• Veins


  • Carry blood toward the heart
  • Most carry oxygen-depleted blood, except for pulmonary veins which carry oxygenated blood
  • Serve as a large reservoir for circulating blood
  • Wall is thinner and more pliable than artery wall
  • Contain valves to prevent backward blood flow
• The peripheral vascular system consists of a network of about 60,000 miles of arteries, arterioles, capillaries, venules, and veins that's constantly filled with about 5 L of blood, which circulates to and from every functioning cell in the body
• Arterial pulses


  • Pressure waves of blood generated by the pumping action of the heart
  • Can be felt where an artery lies near the skin
• Peripheral pulses that can be palpated


  • Temporal
  • Carotid
  • Brachial
  • Radial
  • Ulnar
  • Femoral
  • Popliteal
  • Posterior tibial
  • Dorsalis pedis
• Cardiovascular assessment


  1. Inspect

  2. Palpate

  3. Percuss

  4. Auscultate

  
• Jugular vein distention


  • Indicates venous pressure in the right side of the heart
  • Measured as the distance between the highest point of pulsation and the sternal notch, with the patient's head elevated 30-45 degrees
  • A finding greater than 11/4 to 11/2 inches (3 to 4 cm) above the sternal notch indicates jugular vein distention
• Carotid artery palpation should be done carefully to avoid fainting or bradycardia in the patient
• Normally, no vascular sounds should be heard over the carotid arteries upon auscultation
• Jugular vein distention


  Finding greater than 11/4 to 11/2 (3 to 4 cm) above the sternal notch, with the head of the bed at a 45-degree angle
• Palpating the carotid artery

  1. Lightly place fingers just medial to the trachea and below the angle of the jaw

  2. Pulse should be regular in rhythm and have equal strength in the right and left carotid arteries

  3. Don't palpate both carotid arteries at the same time or press too firmly
• Bruit


  Blowing, swishing sound resulting from turbulent blood flow, can occur in patients with arteriosclerotic plaque formation
• Auscultating the carotid artery

  1. Lightly place the bell of the stethoscope over the carotid artery, first on one side of the trachea, then on the other

  2. Ask the patient to hold their breath if possible to eliminate respiratory sounds
• Cardiovascular landmarks


  • Sternoclavicular area
  • Suprasternal notch
  • Aortic area
  • Pulmonic area
  • Intercostal space
  • Tricuspid area
  • Mitral area
  • Xiphoid process
  • Epigastric area
• Landmark lines


  • Axillary line (anterior)
  • Axillary line (posterior)
  • Midaxillary line
  • Midclavicular line
  • Midsternal line
• Palpating the apical impulse


  1. Use the ball of your hand, then your fingertips, to palpate over the precordium

  2. Note heaves or thrills, fine vibrations that feel like the purring of a cat
• Percussing the heart


  1. Percuss at the anterior axillary line and continue toward the sternum along the fifth intercostal space

  2. The sound changes from resonance to dullness over the left border of the heart, normally at the midclavicular line

  3. The right border of the heart is usually aligned with the sternum and can't be percussed
• Auscultating for heart sounds

  1. Begin auscultation at the aortic area

  2. Listen over all heart valve sites and the entire precordium

  3. Use the diaphragm of the stethoscope to listen as you go in one direction, and use the bell as you come back in the other direction
• Aortic area


  Blood moves from the left ventricle during systole, crossing the aortic valve and flowing through the aortic arch
• Pulmonic area


  Blood ejected from the right ventricle during systole crosses the pulmonic valve and flows through the main pulmonary artery
• Tricuspid area


  Sounds reflect movement from the right atrium across the tricuspid valve, filling the right ventricle during diastole
• Mitral area (apical area)


  Sounds represent blood flow across the mitral valve and left ventricular filling during diastole
• Systole


  Period of ventricular contraction
• Diastole


  Period of ventricular relaxation and filling
• S1


  First heart sound, produced by closure of the mitral and tricuspid valves
• S2


  Second heart sound, produced by closure of the aortic and pulmonic valves
• S3


  Third heart sound, associated with rapid ventricular filling during early diastole
• S4


  Fourth heart sound, associated with atrial contraction during late diastole