CVS part 2 ischemic heart disease (angina) Flashcards
Where is the pain felt in angina?
Severe pressing pain- substernal, neck, shoulders, epigastric due to metabolites that accumulate when there is myocardial ischemia.
What is the cause of angina?
Decreased blood flow and therefore decreased Oxygen to the heart. This can be due to atherosclerosis of the coronary arteries. Often there is endothelial dysfunction & impaired vasodilation meaning even small increases in oxygen demand can induce an attack.
What is the main form of treatment?
Organic nitrates
What are the 2 main types of medications used as prophylaxis of angina?
Calcium channel blockers (cause vasodilation) & beta blockers (decrease HR & contractile force thereby decreasing O2 demand of heart)
Angina is not a disease itself, but usually a symptom of what underlying condition?
Coronary artery disease (CAD)
What is exercise-induced angina (aka Classical/atherosclerotic) angina?
Atheromatous obstruction of large coronary vessels cause inadequate blood flow. Effort increases the heart’s workload which increases O2 demand leading to ischemia and pain.
What is Vasospastic angina (aka Prinzmetal’s Angina/Variant Angina/ Rest Angina)?
A reversible coronary spasm (usually in the vicinity of an atherosclerotic plaque) Pain can occur at anytime.
What is unstable angina (aka acute coronary syndrome)?
Episode of angina occurring at rest. Reoccurring & unpredictable.
Associated with thrombi & platelet aggregation in the vicinity of atherosclerotic plaque & therefore surrounding vasospasm. It is the precursor of a possible MI- emergency.
Who is most likely to develop silent ischemia?
People with diabetes/ who have had a heart attack previously
What is the difference between angina & MI?
With angina: damage to cardiomyocytes is temporary
How can drugs relax vascular smooth muscle?
- Increase cGMP (NO increases cGMP)
- Decreasing intracellular calcium levels (intracellular calcium is needed from vasoconstriction) (beta blockers & calcium channel blockers decrease calcium influx)
- Preventing depolarization of vascular smooth muscle cell membrane
- Increase cAMP in vascular smooth muscle cells
What 3 nitrates are used to treat angina?
Glyceryl Trinitrate, Isosorbide Dinitrate & Isosorbide Mononitrate.
In what 2 ways is Glyceryl Trinitrate administered?
Sublingual (tablet/spray), IV
What brand names are Glyceryl Trinitrate?
Angised, Nitrolingual & Nitrocine
What are the indications for Glyceryl Trinitrate?
Acute angina, hypertensive emergencies & heart failure
What is the MOA of Glyceryl Trinitrate?
Causes release of NO, causing vasodilation & decreasing O2 demand of heart
Key notes of Glyceryl Trinitrate?
Rapid onset; sublingual used for acute relief & IV used for emergencies (acute MI)
How is Isosorbide Dinitrate administered?
Orally, IV, Sublingual
What is sublingual Isosorbide dinitrate used for?
acute relief
What is PO administration of Isosorbide Dinitrate used for?
Prophylaxis
What brand name does Isosorbide Dinitrate fall under?
Isordil
What is Isosorbide Dinitrate used for?
Angina prophylaxis & heart failure
What is the MOI of Isosorbide Dinitrate?
Longer-acting nitrate that dilates veins & arteries, reducing cardiac workload.
Key notes of Isosorbide Dinitrate?
Used for treatment of chronic angina; can develop tolerance
How is Isosorbide Mononitrate administered?
Orally
What brand name does Isosorbide Mononitrate fall under?
Ismo
What is Isosorbide used for?
Angina prophylaxis
What is the MOI of Isosorbide Mononitrate?
It’s an active metabolite of Isosorbide Dinitrate & provides sustained vasodilation
Key notes of Isosorbide Mononitrate?
Longer duration of action than Isosorbide Dinitrate. Used as prophylaxis, not for acute relief.
Which nitrate is short acting?
Glyceryl Trinitrate
What 2 nitrates are longer acting?
Isosorbide dinitrate & Isosorbide mononitrate.
What do nitrates at lower doses cause?
venoselective & vasodilation
What causes nitrate tolerance?
Long-acting nitrates
Chronic use
Compensatory salt & water retention
What do nitrates at higher does do?
Arterial & venous dilation
Sympathetic reflex
What is an NB interaction with nitrates?
Phosphodiesterase inhibitors (PDE5 inhibitors) eg. Sildenafil (viagra)- causes synergistic smooth muscle relation which cause hypoperfusion of organs & MI
What are side effects of calcium-channel blockers?
- Vasodilation related: headache, flushing, palpitations, oedema
- Muscle cramps
- Constipation
- Cardiac suppression
- increased digoxin levels
What 2 CCB drugs are used to treat angina?
Diltiazem & Verapamil (non-dihydropyridines)
How are Diltiazem & Verapamil administered?
Orally
What is Diltiazem used to treat?
Stable & variant angina, hypertension & arrythmias
What is Verapamil used to treat?
Stable angina, hypertension & arrythmias
What is the MOI of Diltiazem?
Inhibits calcium influx in cardiac & vascular smooth muscle, reducing myocardial oxygen demand & causing vasodilation
Key notes of Diltiazem ?
Avoid in heart failure with reduced ejection fraction (HFrEF); caution with beat-blockers
What is the MOI of verapamil?
Similar to Diltiazem but with stronger negative chronotropic & ionotropic effects
Key notes of Verapamil?
Avoid use in severe LV dysfunction; strong CYP3A4 inhibitor
Why should the use of CCB & beta blockers together be done with caution?
Diltiazem & Verapamil suppress pace maker activity & so do beta-blockers. Therefore when used together can lead to extreme bradycardia; severe suppression of AV-node conduction & potent reduction in contractility.
Beta-blockers cause a decreased HR, how is this beneficial in angina?
It increases diastolic perfusion time which may increase coronary perfusion.
Which type of medication is useful in silent angina?
Beta-blockers as they reduce total amount of ischemic time per day
How can the unwanted effects of betablockers (increased ejection time & increased end-diastolic volume) be rectified?
They can be used with nitrates
What 3 types of medications can be used for angina of effort?
Betablockers, long-acting nitrates & CCB
What 2 types of medications can be used to treat vasospastic angina?
CCB & nitrates
What types of drugs can be used to treat unstable angina?
Anticoagulants & anti-platelet drugs (eg. aspirin & clopidogrel); nitrates & beta blockers & CCBs in resistant cases
What type of med can be used to treat silent angina?
Beta blockers that may be combined with other medications
