pharmacology of the CVS Flashcards
what are the symptoms of angina ?
- Feeling of cramping and severe constriction in the chest
- Referred pain - jaw, shoulders neck and arms
- May be associated with shortness of breath, sweating, nausea & heart rate
describe stable angina
- caused by coronary artery disease
- root cause is mainly due to atherosclerosis (plaque build up)
- narrowed coronary artery lumen - restricted blood flow to area of myocardium that it supplies and the oxygen it receives is insufficient so heart has to work harder - anaerobic respiration - pain
characteristics:
* follows a set pattern - predictable
* short duration pain radiates to left arm , neck , jaw and back
* caused by exertion or increased oxygen demand
* not life threatening but can be a warning for something serious
* releived by rest or meds
*
describe unstable angina
- clot blocks lumen in already narrowed artery
- critical lack of blood flow so oxygen supply is even insufficient at rest - pain
characteristics:
* unpredictable
* more severe and longer lasting pain
* happens at rest
* may not have a trigger
* not usually relieved by rest and meds
* can progress from stable angina
* emergency
describe prinzmetal angina
- caused by sudden vasospasm of artery
- critical reduction on blood flow - can happen at rest - pain
characteristics:
* Usually occurs while resting and during the night or early morning hours
* Episodes tend to last around 5 to 15 mins
* Rare
* 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 .
* Associated symptoms include heart burn, nausea, sweating, dizziness,
palpitation, migraines and Raynaud’s phenomenon
* Cocaine use is a leading cause of coronary vasospasms
* Can be relieved by taking medication
describe microvascular angina
- Impaired coronary circulation due to coronary microvascular dysfunction from abnormal vasodilatation or increased vasoconstriction
- Patients do not have obstructive coronary artery disease
- Occurs with exertion and at rest but may respond less well to nitrates.
- Problem diagnosing it early as coronary microvasculature (vessels <300
um in diameter) cannot be directly imaged in vivo - Positron emission tomography (PET) or cardiac magnetic resonance
(CMR) can be used to assess coronary microvascular blood flow - Treatment will vary depending on cause of the microvascular angina
summarise angina pathophysiology
what is the angina treatment strategy ?
To improve perfusion:
* Increase Oxygen Delivery by improving coronary blood flow
* Coronary vasodilators
To reduce metabolic demand:
* Reduce Oxygen Demand by decreasing cardiac work
* Vasodilators
(reduce afterload and preload)
* Cardiac depressants
(reduce heart rate and contractility)
Prevention:
* Prophylactic to reduce the risk of subsequent episodes
* Lipid Lowering Drugs
* Anti-Coagulants
* Fibrinolytic
* Anti-platelet
what is the role of calcium in muscle contraction ?
what is the mechanism of action for nitrates ?
describe nitrates
Examples
Glyceryl Trinitrate, (GTN), Isosorbide Mononitrate
Effects:
Peripheral Venodilation
decrease Total Peripheral Resistance (TPR) reduces Afterload
Both of these actions lower oxygen demand by decreasing the work of the heart.
Note: Limited effect on coronary vessels affected by atherosclerosis
Adverse Effects:
Throbbing Headache, Flushing & Syncope (Arterial dilation)
Postural Hypotension (Venodilatation)
Reflex Tachycardia (Sympathetic outflow)
describe beta blockers
Examples
Atenolol, Bisoprolol,
Effects:
Inhibits I pacemaker current in the sinoatrial node (AV conduction)
Reduce the force of cardiac contractions improves exercise tolerance
Both of these actions reduce cardiac output and lower blood pressure
Slower heart rate lengthens diastole and gives more time for coronary perfusion, which effectively
improves myocardial oxygen supply.
Adverse Effects:
Bronchospasm, Fatigue, Postural Hypotension
Contraindication:
Asthma - block ß2 receptor can cause constriction & bronchospasm
Heart block where atrial-ventrical conduction is poor - may block AV node
what is the mechanism of action for beta blockers ?
describe calcium channel blockers
what is the mechanism of action for calcium channel blockers ?
what are some prophylactic drugs to treat angina ?
give a summary of anti angina drugs
give a summary of angina treatment plan
