Cardiovascular Drugs & Dentistry Flashcards
What does ‘acutely’ mean?
Progresses rapidly
Lasts for a short period
What is acute myocardial infarction caused by?
Thrombosis
What can acute myocardial infarction lead to?
Heart failure
Arrhythmias
Sudden cardiac death
What affects the heart’s energy status and viability?
Coronary artery blood flow
Sympathetic stimulation
Peripheral arterioles/TPR
Central venous pressure sets inotropic state/resting ventricular pressure
How does sympathetic stimulation affect cardiac output?
b1-adrenoceptors activated
Increased rate and force of pumping
Increased cardiac output
What factors improve the energy status of the ventricles?
Increased energy supply
Reduced energy demand
What can increase the energy supply of the heart?
Increased coronary artery supply
What can decrease the energy demand of the heart?
Reduced afterload/TPR
Reduced preload/CVP
Negative inotropy
What is the aetiology of IHD?
Coronary atherosclerosis
Thrombosis
What is coronary atherosclerosis?
Lesion in coronary arteries and laying down of lipid leading to a fat lump
What is acute thrombosis?
Platelets suddenly start clumping on a fissure of an atherosclerotic plaque causing obstruction of vessel
What can provoke angina pectoris?
Increased sympathetic stimulation (eg. exercise)
What are the causes of death in IHD?
Ventricular fibrillation
Heart failure
Stroke
What may be the cause of angina pectoris?
Adenosine (local mediator, ATP metabolism)
Accumulates due to lack of washout
Stimulates nerves = pain
What are the three types of angina pectoris?
Stable angina
Unstable angina
Inappropriate coronary vasospasm (Prinzmetal’s variant)
What is stable angina?
Fixed partial blockage (atheroma)
Exercise or stress causes pain; alleviated by rest
What is unstable angina?
Atheroma fissures and thrombus forms causing full blockage of artery
How do you treat acute angina attacks?
Sublingual GTN/nitroglycerin
Why is GTN not given orally?
Liver metabolises GTN too quickly
What is the mechanism of GTN?
Venodilatation (in capacitance veins)
Reduces central venous pressure/preload
Decreases inotropic state
Decreased energy/oxygen demand
Why does exercise/stress trigger stable angina?
At rest, coronary supply meets demand
Exercise/stress = increased sympathetic stimulation and heart works harder
Vasodilatation
Atheroma cannot dilate so limits maximum flow
Coronary supply cannot meet demand
How do the pharmacokinetics of GTN allow it to work?
Denitrated in bloodstream
NO produced
NO diffuses into smooth muscle and initiates cascade involving cGMP => smooth muscle relaxation
What is a heart attack?
Sudden, symptomatic episode of acute myocardial ischaemia (loss of coronary blood flow) in patients with IHD
What is morphine used for?
Acute myocardial infarction
Reduces stress-related catecholamine drive
