heart conditions Flashcards
(15 cards)
cardiomyopathy
characterized by poor contractility of the muscle that makes up the heart
= low SV = not ejecting blood efficiently
2 common types: dilated and hypertrophic
Hypertrophic cardiomyopathy
Characterized by an increase thickness of the cardiac muscle - usually in the LV wall and ventricular septum
muscle reduced contractility so it compensates with increased = reduced blood flow
dilated cardiomyopathy
characterised by enlarged chambers and thinning of the wall (commonly LA and LV)
starlings law of the heart = greater end diastolic volume means a stronger contraction to help compensate for poor muscle contractility
poor overlap of valves - mitral (left AV) valve can have reduced overlap due to growth of LV and LA
- dont close properly = risk back flow = greater risk of atrial arrhythmias
hypertrophic cardiomyopathy is almost always related to…
genetic mutations at the myofilament - mysoin itself or accessory proteins like troponinx
disrupt contraction by limiting calcium binding at the myofilament - disrupts cross-bridges
easier to diagnose - genetic markers
dilated cardiomyopathy can be caused by…
toxic injury
rare side effect of viral infections (viral myocarditis)
genetic disorders that are highly pronounced
chemo, long-term alcohol/drug use
- harder to diagnose
triggered arrhythmia
local calcium leak triggers an electrical impulse between normal contractions
the cells ahead of that impulse are in their refractory period
however, the ones behind aren’t so the signal moves backwards and interferes with the next contraction
defibrillators
give a big electrical signal to the heart, so all the cells end up depolarising and going into their refractory period at once
arteriosclerosis
over time IEL (elasticity) can become stiff an inflexible - reducing flexibility of artery
advancement = can result in atherosclerosis
atherosclerosis
endothelium and IEL become more susceptible to damage - attracting buildup of fats, cholesterol, ad cellular debris
- lodges within tunica intima below the endothelium
if buildup continues = can develop into a plaque - narrowing luminal space of artery and impending blood flow
susceptibility of athersclerosis is increased by
high blood pressure -more stress/damage
high fat/cholesterol diet - more substrates to create plaques
diabetes mellitus - altered metabolism leads to more fats and cellular debris
genetic predisposition - top risk factor
progression of atherosclerosis
initial fatty deposits in tunica intima cause inflammation and attract white blood cells, which turn into “foam cells”
accumulation of foam cells and additional fats/cholesterol form a fatty streak on the internal wall of the artery
smooth muscle from the tunica media starts to infiltrate into the tunica intima
endothelium of the vessel thickens to cover the plaque and protect the lumen - process greatly decreases elasticity of the wall
eventually plaque forms - fibrous cap - attracting Ca ions that form calcified deposits
slow
myocardial infarction
blockage of coronary arteries prevents blood from reaching areas within the heart
heart tissue - high energy demands - cells within the blockage area die without robust blood supply
= heart attack
can be silent if blockage is small and injuring a small part of the heart slowly
can also happen suddenly - plague rupture
stroke
ischemic stroke occurs when there is a blockage of an artery supplying part of the brain with blood
- brain = high energy demands
blockage can be due to atherosclerosis plaques within the vessels of the brain, or due to plaque rupture elsewhere that then lodges in the small artery tree supplying the brain
stroke can also be haemorrhagic - occurs when a blood vessel ruptures in the brain
pulmonary fibrosis
alveolar membranes thicken, increasing diffusion and reducing permeability of gases
can arise from chronic inflammation or exposure to industrial chemicals
emphysema
decrease in surface area of the lung
membranes separating air sacs in the alveoli break down - reduced surface area
tobacco smoking, air pollution, genetics
