Chapter 3 – Cardiovascular A&P: Age-related changes

The cardiovascular system

• Supplies oxygen to all parts of the body
• A failure in this system creates a cascade of failure in other systems
• Regardless of your Nursing focus, you will encounter cardiovascular concerns in the elderly client due to normal age related changes

Potential challenges for the elderly client

• Electrical
• Force
• Valves
• Coordi-nation

Direction of blood flow of the heart

• Deoxygenated blood:   Right atrium, through tricuspid valve to right ventricle, through pulmonary valve to the lungs
• Oxygenated blood:  Through the pulmonary veins to the left atrium, through the mitral valve to the left ventricle, through the aortic valve to the aorta
• The heart can initiate its own impulse (automaticity), respond to the impulse (excitability), & transmit the impulse (conductivity).  Contractility is mechanical.

Properties of cardiac cells

• Automaticity
• Excitability
• Conductivity
• Contractility

A note on automaticity

• Cells within the heart’s electrical system can generate action potential or electrical impulses without being excited by an external stimuli

Periods of the cardiac cycle

• Diastole:  Period of rest, blood is returned to the heart by veins
• Systole:  Period of contraction, blood is pumped out of the heart by ventricles

The sarcomere

• The functioning unit of cardiac muscle
• Sarcomere composed of 2 proteins:
  • Actin—a thin filament
  • Myosin—a thick filament with projections
• Actin and myosin are kept apart by troponin at rest
• When cardiac muscle cell is stimulated, calcium enters cell
• Calcium reacts with troponin and inactivates it
• This allows actin and myosin to react, causing contraction of the cell

Normal rate and rhythm

• Normal cardiac rate is 60-100.
• Normal rhythm originates in the SA node (sinus rhythm).
• The P waves are regular.
• Every p wave is followed by a QRS complex.

Sinus bradycardia

• Rhythm originates in SA node and is regular.
• Rate is < 60.

Sinus tachycardia

• Rhythm originates in SA node and is regular.
• Rate is > 100.

Irregular heart rhythms

• Rhythm is irregular (rate is variable)

Courses of circulation of the blood

• Pulmonary Circulation (heart-lung)
  • The right side of the heart sends blood to the lungs.
  • Carbon dioxide and some waste products are removed from the blood.
  • Oxygen is picked up by the red blood cells.
• Systemic Circulation
  • The left side of the heart sends oxygenated blood out to all cells in the body.

Normal age related changes

• Heart valves become stiff
• Decreased renin, angiotensin and aldosterone production
• Arterial stiffening and loss of elasticity
• Veins thicken and valvular reflux occurs
• Decreased baroreceptor sensitivity
• Decrease in number of normal pacemaker cells in sinus node
• Myocardial hypertrophy
  • Increased size of myocardial cells
  • Thickening of left ventricular wall

Resulting systemic effects

• Increased resistance of peripheral vessels
• Decreased coronary blood flow
• Reduced cardiac output due to decreased contractility
• Less efficient cardiac oxygen usage
• Increased conduction time results in a longer cardiac cycle
• Slower response to cardiac challenge if not in good physical condition

Nutritional guidelines

• Little to no intake of fried food or animal fats
• Increase intake of complex carbohydrates
• Adjust caloric intake to achieve ideal body weight:
  • M = 106 lbs for 1^st 5’ + 6 lbs for each inch thereafter
  • F  = 105 lbs for 1^st 5’ + 5 lbs for each inch thereafter
• Use monounsaturated oils (olive oil)
• Fish rich in omega-3 fatty acids at least 2x/week
• Reduce red meat, sugar, processed foods
• Limit ETOH

To prevent debilitation from cardiovascular changes through lifestyle modification…

• Remain physically active—30 minutes aerobic activity per day most days of the week
• Avoid obesity—maintain normal BMI between 22-25
• Avoid smoking
• Low doses ASA for most individuals
• Control blood pressure
• Control cholesterol levels
• Restrict sodium intake to 2.4 g/day
• Limit alcohol to ≤2/day for men, ≤1/day for women

Hyperlipidemia

• Elevated cholesterol is a risk factor for cardiovascular disorders
• Remember…Keep HDLs high, keep LDLs low!
  • LDL < 100 mg/dl*
  • HDL > 60 mg/dl*

Atypical presentation of cardiac disease

• Presenting complaint may be heartburn, nausea, fatigue
• Mental status changes
• Dizziness and falls
• Agitation
• Sudden change in cognitive abilities
• New onset atrial fibrillation
• Particularly in women:
  • Fatigue
  • Sleep disturbances
  • Epigastric pain

Heart disease in elderly women

• Symptoms may be unrecognized:
  • Sleep disturbances
  • Intermittent chest tightness, squeezing, pressure
  • Back, neck, stomach, jaw  discomfort
  • Shortness of breath, nausea, lightheadedness
  • Break out in cold sweat

Hypotension

• Frequently associated with medication side effects
• Decreased responsiveness of sympathetic nervous system with age affects autoregulation of cardiac output
• Can result in postural- and/or postprandial hypotension
• Lying/sitting (postural) blood pressure:
• Supine for at least 5 minutes, then check blood pressure
• Check again after 1 and 3 minutes of sitting or standing