Lecture 2 CVD Theme - Symptoms Associated with the Ageing Cardiovascular System Flashcards
What are myocytes?
Muscle cells in the heart
What is the pericardium?
Surrounding sac of the heart
Describe the ageing left ventricle.
Increased after load
Decreased coronary perfusion due to MVO2
Ischaemic potential
Hypertrophy and fibrosis.
What substances lead to hypertrophy and fibrosis of the heart?
TGF, ANG II and aldosterone
What happens when the left ventricle becomes stiff?
Doesn’t load well
Reduced oxygen transfer
Muscular hypertrophy
What leads to angina susceptibility?
Stiffened aorta when the heart contracts and pressure increases. Aorta does not relax fully in diastole so low perfusion through coronary arteries.
Describe ageing valves.
Degenerated collagen on and around valves.
Calcium and lipids deposited on valves.
Valves become hard and stiff so don’t close well.
Collagen and lipid structure degrades the structure leading to valve annulus becoming larger which stretches the valve.
Describe the ageing pericardium.
Collagen fibres become straightened and undergo cross-linking leading to stiffness.
Decreased elastin protein.
More fat deposited.
Increased advanced glycation end products.
Increased TGF.
Increased elastase and MMP activity due to inflammation.
Describe the ageing aorta.
Dilated (more so closest to the heart).
Less springy and pulsatile.
Downward reflection of systolic pressure away from heart is reduced, increasing after load of ventricles.
Describe ageing myocytes.
Large due to compensation for loss of myocytes.
Reduced centrality due to leaky ca channels.
Amyloid deposition contributing to altered ca handling and stiffness.
Describe ageing vessels.
Elastin becomes fragmented.
Collagen becomes cross-linked so stiffer walls.
Less responsive to constriction/dilation as reduction in smooth muscle fibres.
Increase arginine.
Increased endothelial inflammation due to NO reduction as it inhibits endothelial adhesion, platelets and leukocytes.
Describe ageing conduction.
SA node pacemaker cells reduced by over 70%.
Slowing of conduction due to conduction bundles being distorted by fibrous tissue.
Loss of sinus arrhythmia.
Atrial enlargement.
Describe ageing autonomic cardiovascular control.
Reduced baroflex sensitivity.
Reduced response to catecholamines.
Reduced alpha-adrenoreceptor activity.
Reduced vagal activity on HR.
Describe the ageing heart cycle.
Unable to relax in diastole, atria become larger over time trying to push the blood into ventricle.
Less torsion during systole so pumping less effective.
Regurgitant valves means blood may renter the heart.
Aorta less elastic so blood forced back into ventricles.
