Cardiac System and Heart Sounds

Cardiac System Functions

• Delivers oxygen and nutrients to the body by pumping blood.
• The heart is located between the 2nd and 5th intercostal spaces.
• The apex of the heart points down and to the left.

Heart Sounds

• The first heart sound (S1) is caused by the closure of the mitral and tricuspid valves.
• The mitral component (M1) of S1 slightly precedes the tricuspid component (T1).
• The second heart sound (S2) results from the closure of the aortic and pulmonic valves.
• A murmur is caused by turbulence in blood flow and collision currents.
• Three potential causes for a heart murmur include:
  • Increases in velocity (speed) of blood flow
  • Decreases in viscosity (thickness) of blood
  • Structural deficits in the valves or unusual openings in the chambers.

Extra Heart Sounds

• S3: Early ventricular filling, normal in children, and associated with ventricular dilation and fluid backing up (e.g., heart failure) in adults.
• S4: Atrial contraction, associated with a stiff, low compliant ventricle (e.g., ventricular hypertrophy or an ischemic ventricle).

Heart Rate Abnormalities

• The SA node is the heart's "pacemaker" and is located near the superior vena cava.
• Bradycardia is defined as a slow heart rate (less than 60 bpm in adults).
• Tachycardia is defined as a fast heart rate (greater than 100 bpm in adults).
• An abnormal heart rhythm is referred to as cardiac dysrhythmia.
• "Irregularly irregular" describes a heart rhythm with no discernible pattern to the irregularity.
• A pulse deficit is the difference between the apical pulse rate and the radial pulse rate, assessed by simultaneously palpating the radial pulse while auscultating the apical pulse, then subtracting the radial rate from the apical rate; it shows weak contraction of the ventricles.
• The normal adult heart rate ranges between 60 to 100 beats per minute.
• A common heart rate range for a newborn infant is 100-180 beats per minute.

Common Clinical Presentations & Findings

• Artery plaque accumulation occurs in atherosclerosis.
• S1 is loudest at the apex (Mitral area), S2 is loudest at the base (Aortic and Pulmonic areas), using the memory trick 1A (Apex/AV), 2B (Base/Semilunar) - modified.

Auscultation

• Heart sounds are best with the diaphragm of the stethoscope
• Heart murmurs, S3, and S4 are best heard with the bell of the stethoscope

Heart Sound Indications

• An S3 heart sound in an adult might indicate too much fluid, heart failure, or ventricular dilation.
• An S4 heart sound might indicate a stiff, low compliant ventricle, such as in ventricular hypertrophy or an ischemic ventricle.

Assessment Considerations

• It is not acceptable to assess heart sounds through clothing or sheets.
• During palpation of the precordium, the palmar aspect of the four fingers is used to palpate for pulsations and vibrations.
• A thrill in cardiac palpation is a palpable vibration indicating turbulent blood flow.

Auscultatory Areas for Heart Valves

• Second right interspace: Aortic valve area.
• Second left interspace: Pulmonic valve area.
• Fifth intercostal space at the left lower sternal border: Tricuspid valve area (implied by "AV valve" and location relative to mitral).
• Fifth interspace at approximately the left midclavicular line: Mitral valve area.

Infant Assessment

• In infants, the typical apical impulse position is higher and more lateral than in adults, around the 4th intercostal space.
• Murmurs are actually more common in the first days of an infants life, not the other way around.

Pregnancy

Cardiovascular changes:

• Changes in BP (varies with position)
• Increased heart rate (by 10-15 BPM)
• Increased blood volume (by 30-40%)
• Increased cardiac output
• Stroke volume
• Heart sound changes
• A systolic murmur or bruit heard over the breasts is a mammary souffle due to increased blood flow through the mammary vasculature.

Older Canadians and Heart Disease

• Coronary Artery Disease (CAD) is responsible for ⅓ of the deaths of older adults.
• Risk can be decreased by:
  • Quitting smoking
  • Having a good diet
  • Being physically active.

General Cardiac Related Symptoms

• Common cardiac conditions show:
  • Chest pain
  • Dyspnea
  • Orthopnea
  • Cough
  • Fatigue
  • Cyanosis or pallor
  • Edema
  • Nocturia
• Important health history questions must include:
  • Cardiac history
  • Family history
  • Risk factors
• Heavy sweating (diaphoresis)
• Weakness
• Lightheadedness
• Shoulder or neck pain (left)
• Cyanosis or pallor
• Nocturia.

Environment Preparedness

• Preparing a warm, quiet, and comfortable environment will help in a cardiac assessment. Patient privacy is also essential.

Hypertension

• A widened pulse pressure might occur in an older adult with hypertension due to systolic blood pressure (SBP) increasing with age and with stiffening of the arteries, while diastolic blood pressure (DBP) does not change significantly

Peripheral Vascular Review & Assessment

• Orthostatic hypotension is a sudden drop in blood pressure when standing up from a sitting or lying position, more common in older adults.

Arteries in the Arm

• Pulses are commonly assessed using the radial, ulnar, and brachial arteries.

Venous System

• The venous system is considered a low-pressure system because the pressure generated by the heart's pumping action is significantly reduced as blood flows through the arteries, arterioles, and into the capillaries.
• It relies on other mechanisms to return blood to the heart against gravity.
• Contracting skeletal muscles that push blood proximally, pressure gradients during respiration, and unidirectional valves help pump venous blood back to the heart from the legs.
• Problems with the mechanisms of venous return result in venous stasis (slow veins), which can lead to thrombosis (DVT= deep vein thrombosis).
• Prolonged immobility, paralysis, muscle weakness, and conditions that limit movement are risk factors for poor venous return due to the need for skeletal muscle contraction.

Lymphatic System

• The main function is to retrieve excess fluid from tissue spaces and return it to the bloodstream, also filters fluid for microorganisms.
• Edema is a swelling of fluid build-up in the tissues, often due to small blood vessels leaking fluid.
• The two main lymphatic trunks and drainage locations:
  • Right lymphatic duct: Drains the right arm and extending down the right side of the head and thorax (dumps into the right subclavian vein)
  • Thoracic duct: Drains the rest of the body (dumps into the left subclavian vein)
• Lymph nodes: Filter fluid before it is returned to the bloodstream, trapping viruses, bacteria, and other causes of illnesses.
• Swollen and tender lymph nodes indicate local inflammation or infection.

Superficial Lymph Node Groups

• Cervical nodes: Drain head and neck.
• Axillary nodes: Drain the breast and upper arm.
• Epitrochlear nodes: Drain the hand and lower arm.
• Inguinal nodes: Drain most of the lower extremity, external genitalia, and anterior abdominal wall.

Questions to ask patients.

• Any leg cramping or pain?
• Any varicose veins?
• Changes in skin temp, or ulcerations?
• Any swelling or edema?
• Any medications?
• Any swollen lymph nodes?

Assessment of Arms & Legs

• bilaterally compare Symmetry of arms and hands
  • hair pattern
  • color of skin and nail beds
  • temperature
  • texture
  • turgor of skin
  • the presence of any lesions, edema, or clubbing
• Capillary refill is the time it takes for color to return to a blanched nail bed after pressure is applied and released, normal is less than 2 seconds.
  • when assessing pulses, evaluate rate, rhythm, regularity, and force.
• inspect legs for:
  • skin color
  • hair distribution
  • venous pattern, size (swelling or atrophy)
  • any skin lesions or ulcers.
• Palpate temperature of the legs by using the dorsa (backs) of the hands.
• Pitting edema is a severe edema (significant fluid build-up) where an indentation or "pit" remains after pressure is applied to the swollen area. indicates excessive fluid in the interstitial space.
• Varicose veins: Swollen, twisted veins, often in the legs, caused by improper function of the valves within the veins, resulting in blood pooling.
• Risk factors for varicose veins:
  • Obesity
  • Pregnancy
  • Prolonged standing or sitting
  • Family history
  • Increasing age.

Peripheral Arterial Disease (PAD)

• A condition where plaque builds up in the arteries that carry blood to the limbs normally legs, limiting blood flow. Is usually due to atherosclerosis.
• Signs and symptoms of PAD:
  • Painful cramping in hips, thighs, or calves with activity
  • Leg numbness/weakness
  • Ulcers on legs/toes
  • Cold extremities
  • Weak/absent pulses, shiny skin, loss of hair.
• Risk factors for PAD:
  • Smoking
  • Diabetes
  • Obesity
  • Hypertension
  • High cholesterol
  • Family history
  • Increasing age

Pulse Site Palpation

- Sites commonly palpated in the lower limbs (excluding femoral) include popliteal, posterior tibialis, dorsalis pedis.

• Popliteal pulse: With the patient's leg straight but relaxed, anchor your thumbs on the knee and curl your fingers around deep into the popliteal fossa. Press your fingers forward hard to push the artery against the bone (bottom of the femur or top of the tibia). Often found just lateral to the medial tendon.
• Palpating the pulse: it is often impossible to palpate, try 1) gently hyperextending the patient's straight leg while placing one hand behind the knee with fingertips along the midline of the popliteal fossa.

2. Having the patient lie prone and feeling along the line of the artery with the fingertips of both hands.

• Posterior tibialis pulse: locate in the "groove" between the medial malleolus (the bony bump on the inside of the ankle) and the Achilles tendon. Bend your fingers around the medial malleolus, and you may need to slightly dorsiflex the patient's foot.
• Dorsalis pedis pulse: situate on the top of the foot, just lateral to the extensor tendon of the great toe. It requires very light tough and be careful not to mistake your own pulse.

Patient Case Study

• Concerns for this patient: Deep vein thrombosis (DVT) due to immobility (calf pain) and potential pulmonary embolism (coughing, lethargy).
• Assessment that should be completed: A thorough peripheral vascular assessment of both legs, including inspection for redness, swelling, warmth, and palpation of pulses (femoral, popliteal, posterior tibialis, dorsalis pedis), and assessment for unilateral swelling and tenderness in the calf.