Ischemic Heart Disease Flashcards
What arteries are the major supply blood to the heart?
coronary arteries
What is ischemic heart disease?
the imbalance of myocardial oxygen btw supply and demand
What are the causes of ischemic heart disease?
atherosclerosis of coronary arteries
hypotension
severe anemia
Why does atherosclerosis of coronary arteries lead to ischemic?
because it decreases the blood flow around the heart
How does atherosclerosis of coronary arteries decrease blood flow?
increase the resistance to flow
platelet aggregation -> more narrowing arteries
How many % of proximal narrowing vessel can be compensated by distal dilation?
What % ___ cant be compensated? What will resutl?
60%
>70%
ischemic heart disease
What will result when endothelial dysfunction occur?
platelet aggregations and inappropriate constriction of coronary arteries occur
myocardial hypoxia
ATP decreases
What are the consequences of ischemic heart disease?
myocardial hypoxia
accumulation of waste products
necrosis of myocardial tissues
dypsnea
shortness/ difficulty of breathing
pulmonary congestion
the accumulation of blood in the lung
arrhythmias
irregular heart beat
what does high pressure in left atrium & pulmonary veins will cause?
pulmonary congestion & dypsnea
what are the waste metabolites accumulated in the heart if ischemic heart disease occur ?
serotonin, ADP & lactate
What does accumulation of waste products will cause with ischemic heart disease?
angina & arrhythmias
What does myocardial hypoxia cause?
reduction of ventricular systole & distole relaxation
higher diastolic pressure in left atrium & pulmonary veins
What are myocardial oxygen supply dependent on?
oxygen content of blood (constant)
coronary blood flow (manageable)
aortic regurgitation
what is the consequence of this?
the heart valve diseases that keep the aortic valve from completely closing
reverse blood flow from aorta to left ventricle
what will affect the oxygen content of blood?
the amount of Hb concentration & degree of systematic oxygenation
What will influence the coronary flow?
perfusion pressure
local metabolites
coronary vascular resistance
perfusion pressure
What will reduce this pressure?
aortic diastolic pressure
hypotension & aortic regurgitation
What factor will influence the coronary vascular resistance?
the intrinsic coronary tone & the physically impact on coronary arteries
What determine the increase extraction of oxygen from coronary blood flow?
vasodilator vs vasoconstrictor
what are the metabolic factors that vasodilators?
ADP, H+, CO2 & lactate
What are the endothelial cells vasodilator? endothelial cells vasoconstrictor?
NO, prostacyclin & EDHF
Endothelin I
What are the neural vasodilator of coronary vessels? neural vasoconstrictor?
alpha-adrenergic receptor
beta- adrenergic receptor
What is the myocardial oxygen demand dependent on?
ventricular wall stress
HR
contractility
Why does the HR increase require more oxygen?
because the heart require more ATP
What chemical increase the contractility of the heart?
Catecholamine
ventricular wall stress
what is its relationship with oxygen consumption?
the intraventricular pressure divided by the thickness of the wall
the more wall stress, the more oxygen is needed
when can the intraventricular pressure increase?
when there is hypertension or aortic stenosis
intraventricular pressure
the blood pressure within the heart’s ventricles
What happen to the thickness of ventricular wall when it hypertrophy?
What does this mean to the wall stress? To oxygen demand?
the wall getting thicker
reduce the wall stress
oxygen demand decrease
What will result in the ventricular wall hypertrophy?
increase ventricular filling (EDV increases)
coronary perfusion pressure
the pressure that drives the coronary blood pressure
What does the ECG of stable angina different from normal ECG?
ST segment elevates or depresses
T wave invert or become flat line
What is the symptoms of unstable angina different from stable angina?
the exertional pain is more accelerated
the plagues rupture with subsequent formation of clot (thrombosis)
myocardial infarct can occur
Do both stable & unstable angina vasoconstrict or vasodilate?
vasoconstrict
What symptoms does variant angina have?
intense vasospasm although there is no overt plagues
What test can we use to diagnose the silent ischemia?
stressing test with ECG recording
what is syndrome X?
the patients with symptom of angina without demonstrable of atherosclerosis
What drug can we use to treat ischemic syndromes?
what is its effect?
sublingual nitroglycerin
relax the VSMC -> decrease venous return & oxygen demands
coronary revascularization
Examples of some methods?
the methods of restoring the blood flow in coronary vessels
stent, angioplasty, coronary bypass graft
The steps of coronary artery stent
stents, in its orginal collapsed state, is advanced to stenosis, on a ballon catheter
ballon is inflated -> stent expanded
ballon is deflated and catheter is removed, leaving the stent permanently in space
What do beta-blockers drugs do?
decrease the HR and contractility
