Treatment of Angina Flashcards
(37 cards)
Define angina pectoris.
Chest pain due to inadequate supply of oxygen to the heart.
– Typically severe and crushing
– Feeling of pressure and suffocation behind the breastbone
Identify classes of drugs/drugs used to reduce chest pain symptoms.
– Beta-blockers – Nitrates – Calcium channel antagonists – Nirocandil (Potassium Channel Activator) – Ivabradine (If channel inhibitor) – Ranolazine
Identify classes of drugs/drugs used to prolong survival.
– Beta-blockers – Aspirin – Statins – (Angiotensin Converting Enzyme Inhibitors) – (Angiotensin II Receptor Blockers)
Relate the coronary window to angina.
Closing window for coronary flow will increase the risk of angina.
Identify factors which may cause a closing of the window for coronary flow (explain what physiological or pathological change could give rise to each factor).
- Shortening diastole (e.g. increased HR)
- Increased ventricular end diastolic pressure (e.g. aortic valve stenosis)
- Reduced diastolic arterial pressure (e.g. mitral or aortic valve incompetence, heart failure)
Will increasing HR lead to angina in normal healthy people ?
No
Identify possible causes of angina, explaining the causes of each.
- Coronary ischaemia (usually due to atherosclerosis and will lead to angina. If sudden ischaemia, probably due to thrombus and leads to cardiac infarction which in turn will lead to angina)
- Coronary spasms (spontaneous, causes variant angina)
Define cardiac infarction.
“Death of the cells of an area of the heart muscle (myocardium) as a result of oxygen deprivation, which in turn is caused by obstruction of the blood supply”
Name other clinical issues related to cardiac ischemia, other than angina.
Cellular Calcium Overload, may cause cell death and dysrhythmias.
Describe the distribution of pain in angina.
Chest, arm, neck, jaw
List any exacerbating factors for angina.
Exertion, cold or excitement
What is the pain aspect of angina due to ?
Thought chemical factors that cause pain in skeletal muscle (i.e K+, H+ and adenosine) are responsible
How is angina related to heart attacks ?
Angina can accompany or be a precursor of a heart attack
Categorize the different types of angina. What is this classification based on ?
Printzmetal’s variant angina (vasospasm)- Supply Ischemia (reduced oxygen supply)
Chronic stable ischemia (fixed stenosis i.e. atherosclerotic plaque causing reduced blood flow)- Demand Ischemia (oxygen demand increases)
Unstable angina (thrombus)- Supply Ischemia (reduced oxygen supply)
Partly based on what’s causing it.
Does the occlusion response for unstable angina (thrombus) have to be complete ?
No, can be either complete or incomplete
Describe stable angina.
– Predictable chest pain on exertion (because it’s a O2 demand problem) but NOT presenting immediate risk (hence, will mainly treat using drugs to relieve chest pain)
– Caused by a fixed narrowing of the coronary arteries
– Treated by ↓ workload of the heart and ↓oxygen requirement
– Also use drugs to prolong survival (e.g. aspirin, statins, ACE inhibitors)
Describe unstable angina.
–Occurs at rest and with less exertion than stable angina
–Associated with a thrombus around a ruptured atheromatous plaque but without complete occlusion of the vessel (similar to MI)
Describe Variant (Prinzmetal) Angina.
– Uncommon
– Caused by coronary artery spasm
– Not completely understood, but sometimes associated with atherosclerosis
How do antiaginal drugs work, in general ?
Mainly work by ↓ the metabolic demand of the muscle (By decreasing the preload or after-load, or by addressing metabolic demands of the muscle itself)
Give examples of antiaginal drugs, explaining how they reduce angina.
Organic nitrates, nicorandil and calcium antagonists are vasodilators
–↓preload or a fterload
b-blockers and ivabradine slow down the heart
– ↓ the metabolic demand of the muscle (increase window for coronary flow)
Which types of angina are beta blockers used for ?
Important (first line treatment) in the prophylaxis and treatment of stable and unstable angina.
How do beta blockers work in reducing angina ? Give examples of beta blockers.
- Decrease Oxygen consumption by slowing down the heart (block adrenaline or NA binding to beta 1 receptors, hence increase window of coronary flow)
- Also have an anti-dysrhythmic action (reduce risk of death after MI)
Bisoprolol, Atenolol
How do Calcium antagonists work in reducing angina ? Give examples of Calcium antagonists.
• Prevent opening of voltage gated L-type Calcium channels (i.e. block Calcium inflow upon muscle depolarisation)
Mainly affect the heart and smooth muscle
-vasodilator effect mainly on resistance vessels (i.e. reduces afterload)
-also dilate coronary vessels (important in variant angina)
- Verapamil and diltiazem can reduce and impair AV conduction and myocardial contractility
- Amlodipine and lercanidipine more involved with vasculature (i.e. arteries etc) than the heart itself
Two types:
- Dihydopyridine derivatives (e.g. amlodipine and lercanidipine)
- Rate-limiting (e.g. verapamil and diltiazem)
Describe the clinical uses of Calcium antagonists in angina (which calcium antagonists to use for certain situations ? which not to use for certain situations ?)
• Choice depends on comorbidity and drug interactions:
1) Amlodipine or lercanidipine:
- safe in patients with heart failure
- used instead of a Beta-Blocker in Prinzmetal angina or alongside beta-blockers in most angina
2) Diltiazem or verapamil:
- used but contraindicated in heart failure, bradycardia, AV block or in presence of beta-blocker
