Cardiovascular System and Aging Flashcards
What doesn’t change with age
Resting heart rate
Plasma volume and hematocrit
Peak developed tension
Resting length-tension relationship
Changes - properties of the myocardium - excitation contraction coupling
Prolonged activation - inc time to peak tension
Prolonged AP
Prolonged relaxion - longer refractory period
Changes - Passive myocardial properties
Changes in mm tissue materials
Type, amount and distribution of non-contractile protein, collagen and elastin
Changes - Age change - collagen
Inc in collagen
Cross linkage of collagen
Inc in conc of lipfuscin I
Effects of changes with age
Inc stiffness Dec ventricular compliance Impaired diastolic filling LV EDP * Inc exertional dyspnea
Cardiac structure - observations
Left ventricular hypertrophy
Inc LV wall thickness
Inc heart mass
Inc ratio of heart mass/body weight
Cardiac structure - LV cavity dimension
No change
Cardiac structure - net effect of changes
Changes correlate with pressure overload
Cardiac structure - causes of hypertrophy
Inc myocyte size
Inc Collagen and collagen alterations
Inc lipsofusion and other inclusions
Cardiac structure - overall results
Stiffer and more rigid myocardium
Cardiac function - observations
Dec ventricular compliance Prolonged isovolumetric relaxation Dec rate of elderly diastolic filling Inc end diastolic pressure No change in LVEDV
Cardiac function - Cardiac output - Rest
Relatively no change in CO
Cardiac function - Cardiac output - Exercise
Variable changes in SV
Dec max HR
Cardiac Output =
HR x SV
Cardiac function = With exercise young
Inc HR, Dec EDV = SV plateaus
Cardiac function = with exercise aged
Dec max HR, Inc late LVDV = SV
Autonomoic modulation of CV function - Observations
Inc resting + exercise NE
Dec receptor responsiveness
Dec response to catecholamines
Autonomic modulation of CV function - Beta adrenergic effects on blood vessels and HR
Dilation of blood vessels is not as quick
Dec HR?
Autonomic modulation of CV function - Pacemaker cells in the heart - at 75 yo
10% of the pacemaker cells of a 20 yo
Inc cardiac arrhythmia
Atrial fibrillation
Irregular beating of atria
Inc incidence
Artial fibrilation prevalence
more than 10% after 80 yo
Atrial fibrillation Symptoms
Palpitations, shortness of breath, angina
Atrial fibrillation - diagnosis
Physical exam
ECG
Atrial fibrillation - Complications
Heart failure
Stroke
Atrial fibrillation - prognosis
Good with treatment
Sick sinus syndrome - prevalence
Inc progressively with age
Sick sinus syndrome - etiology
Degeneration of sinus node pacemaker cells
Sick sinus syndrome - Symptoms
Dizziness, syncope, fatigue, effort, intolerance, heart failure, angina
Sick sinus syndrome - Diagnosis
ECG Bradycardia
Tachydysrhythmias
Sick sinus syndrome - Treatment
permanent pacemaker
Sick sinus syndrome - complications
inc risk of stroke
Vascular aging - altered vascular properties
Material composition of vasculature
Vascular tree
Ability of peripheral arterioles to dilate dec
Vascular aging - observe with aging
Inc intimal thickening
Fragmentation of elastin
Calcification
Inc collagen
Vascular aging - what inc
Stiffness (dec distensibility)
Arterial pressure (inc systolic)
LV wall thickness
Vascular aging - inc stiffness - from
Inc pulse wave velocity
Dec volume distensibility
Vascular aging - inc aterial pressure because of
Vasculature (aorta) fails to sustain forward flow
Inc LV work with systole
Inc cardiac afterload
Vascular aging - inc LV wall thickness because of
Catecholamine response
Dec VD with exercise (dec exercise tolerance
Cardiovascular reflexes - observe
Dec myocardial response
Dec baroreceptor sensitivity
Cardiovascular performances - dec in functional capacity limits
ability to exercise/work
Cardiovascular performances - Cardiac output changes
Little to no change at rest
Dec with ex
Cardiovascular performances - VO2 max
Dec VO2 max
Cardiovascular performance - Blood pressure changes
Systolic inc throughout life for both M and F
Diastolic inc until middle age and then returns normotensive (50-59)
Clinical implications of age related changes in BP regulation
Orthostatic hypertension
Postprandial hypotension
Situational syncope
Hypotensive response to dec blood volume, preload lowering medications, tachydysrhythmias
