Drugs used in the treatment of ischaemic heart disease Flashcards
Ischemic Heart Disease (IHD)
Ischemic Heart Disease (IHD) results from inadequate coronary perfusion relative to myocardial demand.
Pre-existing (“fixed”) Atherosclerotic Occlusion:
his refers to the chronic, stable narrowing of the coronary arteries due to the buildup of atherosclerotic plaques.
Acute Plaque Change
sudden alterations in the atherosclerotic plaque, which can lead to:
Thrombosis: Formation of a blood clot at the site of the plaque.
Vasospasm: Sudden constriction of the coronary artery.
Which of the following best describes the primary underlying causes of ischemic heart disease (IHD)?
a. Chronic high blood pressure and diabetes
b. Fixed atherosclerotic occlusion and acute plaque change with thrombosis
c. Pulmonary embolism and chronic obstructive pulmonary disease
d. Heart failure and atrial fibrillation
Fixed atherosclerotic occlusion and acute plaque change with thrombosis
Rationale: IHD is mainly caused by pre-existing atherosclerotic occlusion and acute plaque change with superimposed thrombosis and/or vasospasm.
What is the primary mechanism leading to acute coronary syndrome (ACS) in most patients?
a. Chronic myocardial ischemia due to long-standing hypertension
b. Abrupt plaque change followed by thrombosis
c. Progressive heart failure and fluid overload
d. Intermittent episodes of atrial fibrillation
Answer:
b. Abrupt plaque change followed by thrombosis
Rationale: ACS typically occurs due to sudden changes in the atherosclerotic plaque, leading to thrombosis.
.A 58-year-old man with a history of stable angina presents with sudden onset of severe chest pain. Which pathophysiological change is most likely responsible for his condition?
a. Gradual worsening of coronary artery stenosis
b. Acute plaque rupture with superimposed thrombosis
c. Development of pulmonary embolism
d. Sudden onset of atrial fibrillation
Answer:
b. Acute plaque rupture with superimposed thrombosis
Rationale: Sudden severe chest pain in a patient with a history of stable angina is often due to acute plaque rupture and thrombosis, leading to an acute coronary syndrome.
Characteristic chest pain (burning or heavy discomfort behind the sternum), of duration <
15 minutes, due to myocardial ischaemia, usually occurring on exercise and relieved by
rest.
Angina pectoris
Stepwise treatment for angina pectoris (stable)
Beta-blocker:
Atenolol
Add 2nd agent:
Long-acting
calcium channel
blocker:
amlodipine
Add 3rd agent:
Isosorbide
mononitrate /
dinitrate
Organic nitrates
- Glyceryl trinitrate
- Isosorbide mononitrate
- Isosorbide dinitrat
Dilation of collateral vessels that bypass narrowed coronary artery segment
caused by organic nitrates.
Which of the following best describes the function of collateral vessels in the context of coronary artery disease (CAD)?
A) They directly increase the diameter of narrowed coronary arteries.
B) They provide an alternative pathway for blood flow to ischemic myocardium.
C) They create new coronary arteries that replace occluded ones.
D) They do not play a significant role in myocardial blood supply during CAD.
B) They provide an alternative pathway for blood flow to ischemic myocardium.
What is the primary clinical significance of well-developed collateral vessels in a patient with significant coronary artery stenosis?
A) They eliminate the need for any further medical intervention.
B) They contribute to the progression of coronary artery disease.
C) They help preserve myocardial function despite occlusive coronary artery disease.
D) They indicate a higher risk of myocardial infarction.
C) They help preserve myocardial function despite occlusive coronary artery disease.
Organic nitrates: anti-anginal actions
How do medications that reduce pre-load and after-load help in managing CAD?
A) By increasing the diameter of the coronary arteries.
B) By reducing oxygen demand of the myocardium.
C) By stimulating the formation of new coronary arteries.
D) By increasing heart rate.
Answer: B) By reducing oxygen demand of the myocardium.
Which mechanism allows for the redistribution of coronary flow to ischemic areas in CAD?
A) Formation of new coronary arteries.
B) Increased cardiac output.
C) Development of collateral vessels.
D) Vasoconstriction of epicardial arteries
C) Development of collateral vessels
How do collateral vessels contribute to myocardial perfusion in areas affected by coronary artery stenosis?
A) By eliminating the stenosis.
B) By providing an alternative route for blood flow to ischemic regions.
C) By causing vasoconstriction in unaffected arteries.
D) By increasing systemic blood pressure.
By providing an alternative route for blood flow to ischemic regions.
ane’s medication regimen aims to reduce pre-load. Which of the following describes pre-load?
A) The resistance the heart must overcome to eject blood.
B) The volume of blood in the ventricles at the end of diastole.
C) The rate at which the heart beats.
D) The oxygen content of arterial blood.
B) The volume of blood in the ventricles at the end of diastole.
In the management of CAD, why is it important to reduce after-load?
A) To increase the heart rate.
B) To decrease the workload on the heart.
C) To induce coronary artery spasms.
D) To increase myocardial oxygen consumption.
B) To decrease the workload on the heart.
What is the clinical significance of the redistribution of coronary flow to ischemic areas via collaterals?
It enhances blood supply to areas of the myocardium deprived of oxygen.
Which therapeutic strategy is most likely to benefit Jane by reducing both pre-load and after-load?
A) Beta-blockers.
B) Calcium channel blockers.
C) ACE inhibitors.
D) Statins.
c
What role does nitric oxide play in the mechanism of action of organic nitrates?
A) It increases myocardial oxygen consumption.
B) It activates guanylyl cyclase, leading to cGMP formation.
C) It decreases the formation of cGMP.
D) It causes smooth muscle contraction.
B
How does cGMP contribute to smooth muscle relaxation in the context of organic nitrate therapy?
A) By increasing calcium levels in smooth muscle cells.
B) By activating kinases that increase myosin phosphatase activity.
C) By increasing myosin phosphate levels.
D) By inhibiting nitric oxide production.
B
Which enzyme is responsible for the formation of cGMP in response to nitric oxide?
A) Adenylate cyclase.
B) Phosphodiesterase.
C) Guanylyl cyclase.
D) Myosin phosphatase.
C
tolerance and adverse effects
organic nitrates adverse effect are
Hypotension and headache
Organic nitrates: pharmacokinetic and pharmaceutical
aspects: Glyceryl trinitrate
apidly inactivated by hepatic metabolism * Route of administration: sublingual – onset of action = few minutes
converted to di- and mononitrates
* Absorbed through the skin – transdermal patch
* Ineffective if administered orally – first pass metabolism by the liver * Duration of action: 30 minutes
* Due to volatility of the active ingredient, if tablets are opened, the
volatile substance evaporates
* Spray is better, more stable
