Pharmocology Of CVS Flashcards
What is angina pectoris
-disorder of the breast / chest
Cramping or constriction of the chest
Pain in jaw shoulders neck, arms
Shortness of breath, nausea , sweating
What is responsible for the main pain symptom in angina
Ischaemia- reduced blood flow to the heart ! So myocardium does not receive enough oxygen to generate enough atp to pump blood to areas in the body
Affected region in myocardium release lactate,adenosine ,bradykinin, prostaglandin
Activates myocardial pain receptors
Signals sent via sensory neurons to the brain
Pain perceptions
What was the traditional classification of angina
Typical Angina
-substernal chest discomfort of characteristic quality and duration
-provoked by exertion or emotional stress
-relieved by rest or nitrates in minutes
Atypical angina
2 of those synotioms
Non anginal
- only one of those symptoms
New classification of angina ( 4 main types )
- stable angina - coronary heart disease
-unstable angina -due to complications of unstable angina
-prinzmetal angina -due to spasm in coronary arteries
-micro vascular angina -angina symptoms but no evidence of coronary artery disease
Stable angina
- root cause is atherosclerosis
- plaque build up in the arteries
- space for blood flow becomes Smaller
-stenosis
Oxygen is insufficient when blood has to work harder so it leads to anaerobic respiration
Characteristics of stable angina
-follows set pattern
- shirt duration radiation to left arm , neck, jaw , back
-precipitated by excursion / cardiac oxygen increase demand
-nit life threatens but can be warning signs for heart attack / stroke
-relieved by rest
-symptoms attributed to myocardial ischemia
How is an Unstable angina caused
Clot formation occludes artery , critical reduction in blood flow so oxygen in inadequate even at rest which leads to pain
Characteristics of unstable angina
-unpredictable
-pain symptoms more severe
-happens at rest
- no trigger
Relieved by rest and medication
-patients should go hopsital
What causes a prinzmetal angina
Coronary artery spasm , vasospasm produced eg by drugs like cocaine
Which causes critical reduction to blood flow making oxygen supply inadequate leading to pain
Characteristics of prinzmetal angina
-occurs while resting
-rare , present in younger patients
-relieved by taking medication
Pain spreads to head, arms ,
Symptoms - heart burn , nausea,sweating , dizziness, palpitations,migraines
What causes a micro vascular angina
Impaired coronary circulation which leads to reduced coronary perfusion leading to pain
Impaired vasodilation which increases constriction
Characteristics of micro vascular angina
-impaired coronary circulation due to coronary micro vascular dysfunction from abnormal vasodilation or increased vasoconstrictions
-patients do not have obstructive coronary artery disease
-;-PET or CMR Is used to assess coronary micro vascular blood flow
-occurs with exertion at rest
Treatment aims of angina
-enhance quality of life through reduction of symptoms
-improve prognosis and prevent complications such as MI and premature death
-cause minimal side effects
What is angina
An imbalance between the demand and supply of oxygen to the heart
What does vasosspam and thrombus lead to
Decreased coronary blood flow
Which leads to supply ischaemia ( inadequate blood supply due to blockage in the area) which leads to angina
What does fixed stenosis lead to
-increased oxygen requirement
-which leads to demand ischemia ( extreme need for oxygen which exceeds body’s ability to supply ) which leads to angina
Precipating factors of angina
- increased sympathetic activity
-increased contractility - increased vasoconstriction
Role of calcium in muscle relaxation and contraction
- increase in cyctoplasmic calcium ions
-in heart muscle calcium binds to troponin , in smooth it binds to calmodulin
-in the heart troponin causes tropomyosin to move exposing myosin binding site
-in smooth muscle calmodulin leads to phosphylation if myosin
-cross bridge cycle
-contraction by pulling actin along the myosin
How are nitrates and protein kinase G involved in anti anginal pharmacology
- nitric oxide continually produced by the endothelium
- NO leads to production of PKG
PKG reduces smooth musclar tone
—myosin light chain depolarisation , - increased uptake of calcium by SR , less calcium means less contraction so relaxation occurs
-potassium ion channels activated causing hyperpolarisation and closing VGCC
Anti anginal pharmacology - nitrates
Eg GTN, isosorbide mono nitrate
Effects ~ peripheral venodilation -decrease intraventricular pressure- decreases cardiac preload
-arterial dilation-decrease TPR- reduced afterload
Lower oxygen demand and lower work if heart
Adverse effects -
Throbbing headaches , flushing , syncope
Postural hypotension
-reflex tachycardia
Anti anginal pharmacology - b blockers
Eg atenolol , bisoprolol
-inhibits If pacemaker current in SAN which decreases heart rate
-reduce force of cardiac contractions
-reduced cardiac output and lower pressure
Leads to slower heart rate giving more time for coronary perfusion , improves myocardial oxygen supply
Adverse effects
- bronchospasm
-postural hypertension
-fatigue
Anti anginal pharmacology - calcium channel blockers
Amplodipine , nifedipine ,verapamil,diltiazem
-reduce calcium ion entry to cardiac myocytes which reduce contractility
-direct coronary vasodilation
-reduce TPR
Reduce force of contraction
Adverse effects
- lower limb oedema
-flushing and headache
-reflex tachycardia
Caution- blocking calcium channels may alter electrical conduction and contractility
Prophylactic drugs for angina
Aspirin -inhibits COX, reduces thromboxane A2 ,and platelet aggregation
Clopidogrel-inhibits ADP receptors on platelets , reduces aggregation
Statins-HMG CoA reductase inhibitor , reduces cholesterol levels
For people on beta. Blockers or calcium channel blockers whose symptoms are not controlled what other drugs can they take
-ivabradine-inhibitor of if current in SAN which slows sinus heart rate
-Nicorandil-potassium channel activator leads to hyperpolarisation
Ranolazine- late sodium current inhibitor - improves mycardial perfusion
