Angina Flashcards
What are the symptoms of angina?
- Tightness
- Squeezing
- Crushing sensation in the chest
- Referred pain to left arm/left jaw
What is unstable angina?
- Fibrous cap has been eroded
- Very thrombotic plaque
- doesnt follow a pattern
- more severe
- can occur with/without physical exertion at rest or medicine may not relieve the pain
What is atherosclerosis?
- The build up of cholesterol rich plaques
- The disease process leading to CHD
- causes stenosis of coronary arteries
Describe the 2 components of an atherosclerotic plaque.
- ) Fibrous cap: SMCs and CT
2. ) Atheroma: soft pool of extracellular lipid, cell debris,activated immune cells. Progressively calcifies over time
What may thrombosis lead to?
- unstable angina
- STEMI
- NSTEMI
What may cause angina?
- exertion/emotion
- results from increased oxygen demand with restricted blood flow due to fixed stenosis
What may cause angina of effort?
- exertion/emotion
- results from increased oxygen demand with restricted blood flow due to fixed stenosis
At which level of stenosis does angina develop?
-Stenosis of > or= 70%
How can decreased oxygen in cardiac tissue lead to coronary vasodilation?
- The decrease in oxygen in the cardiac tissue results in a release of protons & bradykinin
- This leads to activation of TRPV1 on sensory nerves which causes pain and the release of substance P
- This subsequently leads to coronary vasodilation
What are the different types of angina?
- ) Angina of effort
- ) Mixed(variable threshold angina)
- ) Vasospastic(Prinzmetal’s) angina:
- ) Microvascular (syndrome X)
- ) Unstable
Outline mixed angina.
- unpredictable, develops at different levels of exercise
- common
- probs due to stenosis&vasospasm
Outline vasospastic (Prinzmetal’s) angina.
- decreased oxygen supply
- due to spasm of coronary artery- tight enough constriction to cause ischemia
- can occur at rest
- often at night
- Transmural ischemia cos all layers of the heart wall are affected due to the tightness of the constriction
- Patients may/may not have atherosclerosis with it
Outline micro vascular(syndrome X) angina
-Chest pain
-Normal coronary angiogram
-Positive exercise test
-Endothelial dysfunction
-Constricted microvasculature
-Occurs more commonly in women.
with signs associated with decreased blood flow to heart tissue but with normal coronary arteries.
-Coronary arteries are normal
Outline unstable angina
- decreased oxygen supply
- due to transient formation of a non-occlusive thrombus
- an acute coronary syndrome
What can we use for immediate relief/short term prevention of angina?
-Short acting nitrate
What can we use for ongoing prophylaxis of angina?
- Beta blockers
- long acting nitrate
- ivabradine
- nicrorandil
- ranolazine
How can we treat angina
- GTN
- rest
Outline the use of organic nitrates in angina
- cellular mechanism= NO donor
- Haemodynamic mechanism: decreased CVP/preload, leads to and increased coronary blood flow
- GTN taken sublingually= v rapid &used for cutting short an angina attack of preventing an anticipated attack
- Other organic nitrates are longer acting and are taken on an ongoing basis( pills,ointments,patches)
How is the effectiveness of longer acting nitrates limited? How can this be avoided?
- development of TOLERANCE
- Can be avoided by a daily 8 hour drug free period (typically at night)
Outline the haemodynamic effects of nitrates.
Major actions:
-relax venules & veins, so decrease CVP and thus decreases cardiac wall tension so decreases cardiac demand
Minor actions:
-Dilate larger coronary arteries, increasing blood flow through coronary collaterals
-decrease TPR and afterload, therefore decreasing oxygen demand
Side effects:headache, facial flushing, decreased BP, reflex increase HR
What is the aim of drug treatments for angina?
- Limit the number, severity& sequellae of anginal attacks, thereby improving QOL
- main mechanism is to decrease cardiac oxygen demand
- secondary mechanism= increase the o2 supply to the ischaemic zone by decreasing the HR and increasing the blood flow in coronary arteries
- protect against the future
What is Ivabradine used for?
- Decreases heart rate because it inhibits the funny current
- Decreases force of contraction
- Increases perfusion
What is Ranolazine used for
- Anti-anginal medication
- Decreases wall tension
- By blocking late inward sodium currents, calcium overload and diastolic wall stress are reduced, leading to improved coronary blood flow.
- prevents arrythmias
Which drugs can be used to treat angina?
-Ivadbradine
-Beta blockers
-Ranolazine
-Nitrates
(Calcium channel blockers-e.g amylodipine and potassium-ATP channel activators-e.g nicorandil also)
