Pharmacology of CVS Flashcards
What is angina pectoris
Feeling of cramping and severe constriction in the chest
May be associated with shortness of breath, sweating, nausea and increase heart rate
How is angina pain stimulated
1) Angina pain originates from heart muscle when there is a build up of lactic acid during anaerobic respiration
2) Activates myocardial pain receptors
3) Signal sent via sensory neurones (cardiac nerves and upper posterior nerve roots) to the brain
4) Pain perception
Traditional classification of angina
Typical angina
Atypical angina
Non-anginal
Typical angina
- Substernal chest discomfort of characteristic quality and duration
- Provoked by exertion or emotional stress
- Relieved by rest and/or nitrates within minutes
New classification
Stable angina
Unstable angina
Prinzmetal angina
Microvascular angina
Stable angina aetiology
1) Narrowed coronary artery lumen
2) Restricted blood flow to area to myocardium it supplies
3) The oxygen it receives is insufficient when the heart must work harder
4) Anaerobic respiration
5) Pain
Characteristics of stable angina
- Follows a set pattern/predictable
- Recurrent episodes tend to have similar onset pattern, duration, and intensity
- Short duration radiation to left arm, neck, jaw or back
- builds to a peak and lasts 2-5 minutes
- Precipitated by exertion/ increase cardiac O2 demand
- Not life threatening but can be warning sign for something serious e.g. Heart attack/stroke
- Relieved by rest or taking medications
- Symptoms attributed to myocardial ischemia
Unstable aetiology
1) Clot formation occludes artery
2) Critical reduction in blood flow so that oxygen supply is inadequate at even at rest
3) Pain
Characteristics of unstable angina
- Unpredictable
- Pain symptoms more severe, can persist and lasts longer
- Happens at rest with little exertion
- May not have a trigger
- Not usually relieved by rest and medications
- Progression from stable angina – impossible to predict who will progress
- Serious, regarded as emergency, patients are advised to go to hospital
- Is an emergency because it could be MI. part of heart dies, and it doesn’t regenerate
Prinzmetal angina aetiology
1) Coronary spasm (can be caused by drugs like cocaine)
2) Critical reduction in blood flow so that oxygen supply is inadequate (can happen at rest)
3) Pain
Characteristics of Prinzmetal angina
- Associated symptoms include heart burn, nausea, sweating, dizziness, palpitation, migraines and Raynaud’s phenomenon
- Usually due to a spasm in the coronary arteries and tends to come in cycles
- Usually occurs while resting and during the night or early morning hours
- Episodes tend to last around 5 to 15 minutes (longer in some cases)
- Rare (1 in 100 angina cases)
- Younger patients present with this kind of angina
- Attacks are usually severe – described as very painful
- Pain may spread from the chest to the head, shoulder, or arm
- Cocaine use is a leading cause of coronary vasospasms
- Can be relieved by taking medication
Microvascular aetiology
1) Impaired coronary circulation
2) Reduced coronary prefusion
3) Pain
The capillaries going through constriction
Impaired vasoconstriction - due to endothelium due to release of NO
Characteristics of microvascular angina
- Impaired coronary circulation due to coronary microvascular dysfunction from abnormal vasodilation or increased vasoconstriction
- Patients do not have obstructive coronary artery disease
- Occurs with exertion and at rest but may response less well to nitrates
- Treatment will vary depending on cause of the microvascular angina
What are the aims of treatment
- To enhance quality of life through reduction of symptoms
- To improve prognosis and prevent complications such as MI and premature death
- Well tolerated, and cause minimal side effects
Precipitating factors for angina
Increase sympathetic activity
Increase contractility
Vasoconstriction
Angina treatment strategy
Improve perfusion
Reduce metabolic demand
Prevention
