Angina Flashcards
Angina (definition)
- Chest pain due to inadequate delivery of oxygen to the cardiac muscle.
- Imbalance between cardiac oxygen supply and cardiac oxygen demands
Ischemia
Deficient supply of blood to a body part that is due to obstruction of the inflow of arterial blood.
- in some individuals the ischemia is not accompanied by pain (slient angina)
- In severe cases the pain migrates to the left arm
- Pain is caused by accumulation of metabolites in the myocardium
Angina (characteristics)
You will have:
- ST depression, T wave depression (85% of the time); or ST elevation, T wave elevation (much less common)
- Increase in troponin C
- Decreased cardiac contraction
Coronary circulation
- The heart has a smaller blood supply compared to its O2 demand
- Arterial pressure
- Cardiac cycle- flow occurs mainly in Diastole and less during systole.
- Direct sensitivity of arterioles to aneaerobic metabolites (adenosine and ADP)
Stable angina
-chronic stable angina- exertional (O2 demand > than the O2 supply) -most common - cause: artherosclerotic narrowing Treatment Goal: Increase O2 supply and decrease O2 demand
Unstable angina
- worsening of stable
- -AMI
- sudden death
- O2 supply decreased when demand is unchanged (at rest)
- Causes: plaque rupture
Variant angina (Prinzmetal’s)
Recurrent episodes of RESTING pain with REVERSABLE ST elevation and preserved exercise tolerance
-Cause: Coronary vasospasm
TREATMENT GOAL: Increase O2 Supply
Risks for Ischemic Heart Disease
- HTN
- smoking
- hyperlipidemia
- hyperglycemia
- male
- post menopausal female ( low estrogen)
Angina precipitating factors
- Exercise
- Stress
- Sex
Purpose of treatment
- relieve symptoms
- stop the disease process
- regression of the process
- prevent MI
Basis of Drug Therapy
Decrease the O2 demand by reducing workload: -decrease HR -decrease force of contraction -decrease afterload Increasing the SUPPLY of O2
Antianginal Drugs (6 classes)
- Nitrates
- Beta antagonists
- Calcium channel blockers
- Ranolazine
- Antithrombotic
- Anti lipidemic
Organic Nitrates (MOA)
- relaxation of smooth muscle, mostly venous but some arterial dilation as well
- nitrate (NO2) is converted to NO, causes an increase in cGMP formation which leads to Ca2+ sequestration (prevents contraction / mechanism of vasodilation)
Nitrates (therapeutic effects)
- Arteriolar dilation (decreases afterload)
- Venous dilation (decreases preload)
- relieves vasospasm
- redistrubutes myocardial blood flow
Nitrates Side Effects
-headache
-hypotension
-fainting risk
Contraindicated : hypersensitivity, hypotension, Increased ICP, constrictive pericarditis/ tamponade, severe anemia
Nitrates FYI
- dose/effect is inversely related to vessel diameter; smallest dose will dilate veins, largest dose needed for arteriolar dilation
- tolerance can develop
- extensive 1st pass metabolism
- stimulation of SNS
- may ellicit angina attack “steeling effect/ reflex tachy”
Isorbide (isordil)
- organic nitrate
- SE: flushing methlaemoglobinaemia (at high doses only), headache, orthostatic hypotension
-interaction with phosphodiesterase 5 inhibitors (sildenafil/VIAGRA): DO NOT USE WITH NITRATES: (nitrates increase cyclic CMP; phosphodiesterase-5 inhibitors increase cGMP by preventing its breakdown; phosphodiesterase 5 breaks down cGMP)
Beta blockers (effects)
-blockade of sympathetic stimulation
-decrease HR
-decrease contractility
-decrease systolic wall tension
- Increases time spent in diastole / prolonging perfusion
Decrease incidence of MI in patients with CAD
Beta blockers (therapeutic use)
-angina
-post MI
-CHF
Contraindicated in prinzmetal’s angina
Avoid non selective in patients with asthma (bronchospasm)
Beta blockers (Side effects)
- fatigue
- lethargy
- impotence
- bradycardia
- bronchospasm
Calcium channel blockers (ther. effects)
- decrease HR
- decrease contraction (limits Ca entry during plateau)
- inhibits ectopic beats
-decreases afterload (arterial vasodilation)
Calcium channel blockers (list)
- nifedipine (works only on vascular NOT heart)
- diltiazem
- verapamil
- bepridil
Calcium Channel Blockers (therapeutic uses)
- angina
- variant angina
- HF
- HTN in SAH hemorrhage
- arrhythmias
Calcium Channel Blockers (side effects)
-dizziness
-flushing
-headache
-transient hypotension
-per. edema
-bradycardia
-AV block
Do not use with beta blocker combo due to INcrease risk of AV block
Ranolazine (Ranexa)
- treatment of chronic stable angina
- blocker of late Na+ channels
- metabolized by cytochrome 450(CYP3A4)
- 3 days to become effective
- Do not use in patients with prolonged QT, hepatic or renal impairment
- Do not combine with dlitiazem (decreases absorption), or potent CYP3 inhibitors (ketoconozale, simvastatin)
Ranolazine Side Effects
- constipation
- dizziness
- headache
- nausea
- peripheral edema
- asthenia (loss of strength)
other agents for Angina
- ASA 325 mg/day
- statins
Nitrates and beta blocker combo
nitrates attenuate adverse cardiovascular effects of beta blockers. Beta blockers inhibit the tachy and positive inotropic effects of nitrates
nitrates and calcium channel blockers
- only in supervised clinics
- use for severe exertional or vasospastic angina
- severe hypotension and bradycardia can occur
Beta blocker and calcium channel blockers
- only in patients with heart disease when with nifedipine or amiodipine are used (they work only on vascular).
- Do not combine with calcium blockers that work on heart because of AV BLOCK
