Cardiovascular Aging Pt. 2 Flashcards
what causes degeneration of elastin and increased collagen in arteries
aging, which leads to changes like crosslinking and Ca2+ buildup
what happens to systolic and diastolic pressure with age
systolic pressure increases and diastolic pressure decreases due to arterial stiffening
what is the effect of endothelial dysfunction of blood pressure
causes vasoconstriction, increased peripheral resistance, and increased systolic pressure
how much does systolic pressure increase from 20-80 YO
~30mmHg
~80% of the population have _______ by 80 YO
have isolated systolic hypertension
what does aortic impedance represent
left ventricular afterload
what is left ventricular afterload
the force needed from the LV in order to eject blood into the aorta
what does increased and earlier wave reflection contribute to
aortic pressure during systolic and affects coronary perfusion
wear and tear of the arteries is a result from
fracture of aortic elastic lamellae
how is a pulse wave generated
by each ejection of stroke volume from the left ventricle
what is a pulse wave reflection
when a pulse hits a branching point in the arteries and bounces back toward the heart
what happens to a pulse wave when is hits a bifurcation point
a reflected wave is generated and returns back to the heart
what affects the timing and velocity of the reflected wave
depend on the stiffness of the large elastic arteries
what is the augmentation pressure determined by
the size and timing of the reflected wave and is a reflection of arterial stiffness
what happens to the reflected wave in younger more elastic arteries
the reflected wave is slow and reaches the heart during diastole
what happens to reflected wave in older more stiff arteries
the reflected wave gets back to the heart sooner during systole
when does the blood enter the coronary arteries occur
during the diastolic phase of the cardiac cycle
what does early wave reflection result in
less contribution to coronary circulation during diastole
what does the heart do to pump into stiffened arteries
it maintains a higher force of contraction
what happens due to more forceful ejection in stiffened arteries
a pulse pressure that extends into the microvasculature
what is the risk of fragile capillaries due to high pulse pressure
higher risk of thrombosis and rupture
what happens to augmentation and pulse pressure in stiff large arteries
they both increase
how does pulse travel through stiff large arteries
travels faster, and is measured as pulse wave velocity (PWV)
what is PWV related to
the intrinsic elasticity of the arterial wall
where does earlier wave reflection occur
in stiff large arteries
what is high plasticity in the cerebral microcirculation associated with
changes in the brain commonly seen in Alzheimer’s disease and other types of dementia
what are cardiac consequences of increased systolic blood pressure
- Increased left ventricular afterload
- higher force
- greater force required and larger muscle mass means higher metabolic demands of the heart
- coronary perfusion
what are the results of cardiac metabolic demand exceeds blood supply
myocardial ischemia
what is coronary perfusion during diastole
when blood flows into the coronary arteries
what are the consequences of aging on coronary perfusion
- shorter duration of diastole
- decreased diastole blood pressure
- early wave reflection
what is shorter duration of diastole due to and result in
LV hypertrophy and slower rates of LV relaxation resulting in less time for blood to flow into coronary circulation
what is myocardial ischemia
insufficient blood flow to meet metabolic demands of the left ventricle
what are the consequences of myocardial ischemia
angina pectoris and arrhythmias
what is angina pectoris
chest pain due to myocardial ischemia
what is arrhythmias
heart rhythm disturbances
what is myocardial ischemia arrhythmias due to
metabolite build up and increased fibrosis within the myocardium
what does myocardial ischemia lead to
build up of metabolites in the coronary bloodstream
what occurs overtime due to myocardial ischemia
the overworked and under oxygenated heart muscle fatigues increasing the risk of heart failure and congestive heart failure (CHF)
what are the mechanisms of pathological ventricular remodeling
1) cardiomyocyte loss, cardiomyocyte hypertrophy, and fibrosis
2) lead to ischemic phenotypes and hypertrophic phenotypes
3) results in heart failure
what is heart failure
when the ventricle has weakened and can no longer maintain the cardiac output required
what is the cause of heart failure
- coronary artery disease
- chronic uncontrolled high systolic blood pressure
- arrythmias or heart attack that has weakened the heart muscle
what is a congestive heart failure
blood back up that results in fluid to be forced out of capillaries and into surrounding tissues
what are the mechanisms that atherosclerosis accelerates the progression of CVD
1) plaque formation
2) Inflammation
3) increased blood pressure
4) reduced oxygen supply
5) endothelial dysfunction
what is plaque formation regarding atherosclerosis and the progression of CVD
build up of fatty deposits that narrow the arteries, reducing blood flow to the heart
what is inflammation regarding atherosclerosis and the progression of CVD
the plaques cause chronic inflammation which can weaken the arterial walls and make them more prone to rupture
what is increased blood pressure regarding atherosclerosis and the progression of CVD
narrowed arteries force the heart to pump harder to push blood through
what is reduced oxygen supply regarding atherosclerosis and the progression of CVD
when plaques can block blood flow, reducing the oxygen supply to the heart muscle
what is endothelial dysfunction regarding atherosclerosis and the progression of CVD
atherosclerosis damages the endothelium impairs its ability to regulate blood flow and clotting
what are the effects of aging on blood pressure regulation
central control of blood pressure by the baroreceptor reflex
what are baroreceptors located in
in the walls of the carotid artery and aortic arch
what do baroreceptors respond to
increased BP by increasing firing rate
where does the baroreceptor reflex signal to
the cardiovascular control center in the medulla
what is the baroreceptor reflex response
to restore BP
what are the effects of aging on BP regulation impaired by
- stiffer blood vessels
- decreased baroreceptor sensitivity to stretch
- decreased SNS response of heart and vasculature
what does aging and systolic BP elevation cause
impaired BP regulation that results in acute hypotension then cerebral hypoperfusion
what are symptoms of BP regulation
light-headedness, dizziness, blurred vision, weakness, nausea, and feeling faint
what are the consequences of BP regulation
syncope, falls, and long term cognitive dysfunction, increased morbidity, and mortality
what is orthostatic hypotension
a drop of BP of at least 20 mmHg (systolic) and/or at least 10mmHg (diastolic) when moving from a supine position to upright within 3 minutes of standing
what is orthostatic hypotension due to
an impaired BP response to the drop in venous return that normally occurs on assuming an upright position
~ 30% of adults greater than 70 YO experience what
orthostatic hypotension
what is the treatment for orthostatic hypotension
maintain a healthy water intake, healthy salt intake, compressions stockings, and slight inclined position while sleeping
