Ischaemic Heart Disease

Question 1

What is ischaemic heart disease?

Answer 1

Ischaemic heart disease is a group of clinical syndromes usually caused by atherosclerosis of the coronary arteries.

Question 2

What are the clinical manifestations of ischaemic heart disease?

Answer 2

The clinical manifestations of ischaemic heart disease include angina, myocardial infarction (MI), and heart failure (ischaemic cardiomyopathy). Less commonly, it can cause arrhythmias and mitral valve dysfunction.

Question 3

What is another term for ischaemic heart disease?

Answer 3

Ischaemic heart disease can also be referred to as coronary artery disease.

Question 4

Who is more commonly affected by ischaemic heart disease?

Answer 4

Ischaemic heart disease is more common in men.

Question 5

At what age group does ischaemic heart disease have a higher mortality rate?

Answer 5

Ischaemic heart disease has a higher mortality rate over the age of 75.

Question 6

Are there any geographical factors associated with the incidence of ischaemic heart disease?

Answer 6

Yes, there is a higher incidence of ischaemic heart disease in areas of deprivation and in the north and Wales.

Question 7

What are the common clinical symptoms of angina?

Answer 7

The clinical symptoms of angina include chest pain, discomfort, or ache. It typically occurs during exertion and settles within 2-10 minutes. The pain is often described as tight, dull, squeezing, and heavy. It is poorly localized across the chest and may radiate to the arms, throat, and teeth.

Question 8

What factors worsen angina symptoms?

Answer 8

Angina symptoms can worsen in cold environments or after a large meal.

Question 9

What is demand ischemia?

Answer 9

Demand ischemia refers to inadequate blood flow to the heart when demand increases, such as during exertion, after a large meal, or due to tachyarrhythmias. It occurs in the presence of a fixed obstruction in the coronary arteries.

Question 10

What is cardiac pain and how is it perceived?

Answer 10

Cardiac pain is referred pain, which means it originates from visceral (organ) sources but is perceived in somatic regions innervated by the same spinal segments as the heart. Typically, cardiac pain is felt in the chest (T1-5) and shoulder (C5-6) regions and is less likely to affect the distal arm (C7-8).

Question 11

How is cardiac pain carried to the brain?

Answer 11

Cardiac pain is carried via cardiac sympathetic afferent nerves to the spinothalamic tract, then to the thalamus, and finally to the cerebral cortex.

Question 12

What are the clinical symptoms of myocardial infarction (MI)?

Answer 12

The clinical symptoms of MI include severe and persistent chest pain or discomfort. The pain is often described as tight, dull, squeezing, and heavy. It is poorly localized and may go across the chest. It can also radiate to the arms. Associated symptoms may include malaise, nausea, breathlessness, and sweating.

Question 13

What causes supply ischemia in ischemic heart disease?

Answer 13

Supply ischemia in ischemic heart disease is caused by acute coronary artery occlusion or blockage, leading to inadequate blood flow even to cover the basal requirements of the heart cells.

Question 14

What are the components of atherosclerosis?

Answer 14

Atherosclerosis involves a lipid-rich core and a fibromuscular cap.

Question 15

What can lead to coronary thrombosis in ischemic heart disease?

Answer 15

Coronary thrombosis can occur due to plaque rupture, particularly in vulnerable plaques with thin caps exposing collagen and lipid. This exposed surface is thrombogenic, leading to platelet adhesion and the formation of a platelet thrombus. The clotting system is then activated, resulting in the formation of a red thrombus.

Question 16

How can occlusion or embolism contribute to the complications of ischemic heart disease?

Answer 16

The occlusion or embolism caused by the formation of a thrombus in the coronary arteries can lead to complications such as myocardial infarction, where a portion of the heart muscle is deprived of blood supply, resulting in tissue damage or death.

Question 17

Why can heart failure result from ischemic heart disease?

Answer 17

Heart failure can result from ischemic heart disease due to supply ischemia caused by acute coronary artery occlusion. Inadequate blood flow to the heart, even to meet basal requirements, can lead to impaired heart function and eventually heart failure.

Question 18

What is the ischemic cascade?

Answer 18

The ischemic cascade describes the sequence of events that occur as ischemia (reduced blood flow) progresses over time. It includes hypoperfusion (reduced blood flow), metabolic disturbance leading to arrhythmias, diastolic dysfunction, systolic dysfunction, ECG changes, chest pain, and myocyte necrosis.

Question 19

What are the symptoms of heart failure?

Answer 19

Heart failure can cause fatigue due to low cardiac output (CO) and fluid retention. Symptoms of fluid retention include leg swelling, breathlessness (cough), worsened breathing while lying flat (orthopnea), and waking up at night gasping for breath (paroxysmal nocturnal dyspnea). Approximately 50-70% of heart failure cases are due to ischemic heart disease (IHD), including previous myocardial infarctions (MIs) and chronic ischemia.

Question 20

What is silent ischemia?

Answer 20

Silent ischemia refers to a condition where the first sign of ischemic heart disease may be sudden death. It can occur due to acute occlusion of non-obstructive plaques or in cases of obstructive disease with “silent ischemia.” There is strong evidence supporting the benefits of preventive medication in such cases, but there is no ideal screening test available. Exercise ECG has low sensitivity and specificity and is labor-intensive, while cardiac CT is expensive and carries a radiation risk.

Question 21

What are the general principles of management for all patients with ischemic heart disease (IHD)?

Answer 21

The general principles of management for all IHD patients include lifestyle changes, risk factor management, and anti-thrombotic therapy. Additionally, medical treatment for symptoms, revascularization for chronic, severe disease, acute reperfusion treatment for ST-elevation myocardial infarction (STEMI), and cardiac rehabilitation are important considerations.

Question 22

What are the lifestyle modifications recommended for IHD patients?

Answer 22

Lifestyle modifications for IHD patients include smoking cessation, weight optimization, adopting a low-saturated fat diet, and engaging in regular aerobic exercise.

Question 23

How is risk factor management approached in IHD patients?

Answer 23

Risk factor management in IHD patients involves addressing specific factors such as hypertension, hyperlipidemia, and diabetes. This can include lifestyle modifications, such as weight loss and reducing salt or saturated fat intake, as well as medications like ACE inhibitors (e.g., ramipril) for hypertension and statins (e.g., atorvastatin) for hyperlipidemia. For diabetes, optimizing glycemic control through dietary changes and medications such as metformin and insulin may be recommended.

Question 24

What are the treatment options for chronic, severe disease in IHD?

Answer 24

Revascularization is an option for chronic, severe disease in IHD. This can involve procedures such as angioplasty (percutaneous coronary intervention) to open narrowed or blocked coronary arteries.

Question 25

What is acute reperfusion treatment for STEMI?

Answer 25

Acute reperfusion treatment is essential for ST-elevation myocardial infarction (STEMI). It typically involves urgent restoration of blood flow to the blocked coronary artery, which can be achieved through emergency angioplasty or thrombolytic therapy.

Question 26

What is coronary artery bypass grafting (CABG)?

Answer 26

Coronary artery bypass grafting (CABG) is a surgical procedure that involves creating new pathways for blood to bypass blocked or narrowed coronary arteries. This is done by using healthy blood vessels (grafts) from other parts of the body to create detours around the blockages.

Question 27

Are there any factors that can influence the risk of IHD?

Answer 27

It has been observed that being younger and female may confer a lower risk of developing ischemic heart disease.

Question 28

What are the commonly used anti-platelet drugs in the treatment of ischemic heart disease?

Answer 28

Anti-platelet drugs used in the treatment of ischemic heart disease include cyclooxygenase inhibitors like aspirin, ADP receptor antagonists such as clopidogrel, and GP 2b/3a antagonists like tirofiban.

Question 29

Which anticoagulants are typically used in the management of acute myocardial infarction (MI)?

Answer 29

Anticoagulants commonly used in the management of acute MI include intravenous heparin, low molecular weight heparin, and fondaparinux. These drugs help prevent further clot formation and promote blood flow.

Question 30

What are the commonly prescribed anti-anginal medications?

Answer 30

The three main classes of anti-anginal medications are beta-blockers, calcium channel antagonists, and nitrates.

Question 31

How do beta-blockers work in the treatment of angina?

Answer 31

Beta-blockers block cardiac beta-1 receptors, reducing the force of contraction and the heart rate response to exercise. Examples of beta-blockers used in angina treatment include bisoprolol.

Question 32

How do calcium channel antagonists function as anti-anginal drugs?

Answer 32

Calcium channel antagonists reduce calcium entry into myocytes and vascular smooth muscle, resulting in reduced force of heart contraction. They also dilate coronary arteries, lower blood pressure (reduced afterload), and can include medications like amlodipine and diltiazem.

Question 33

What are the actions of nitrates in treating angina?

Answer 33

Nitrates mimic the actions of nitric oxide (endothelium-derived relaxing factor) and have several effects. They dilate coronary arteries, dilate veins more than arteries (reducing venous return/preload), and are available in both short-acting forms like GTN spray and long-acting forms like isosorbide mononitrate.

Question 34

What are the main branches of the left coronary artery?

Answer 34

Left anterior descending artery (LAD) - supplies approximately 45% of the left ventricle.
Circumflex artery - supplies approximately 20-30% of the left ventricle.
What is the approximate distribution of the right coronary artery?
The right coronary artery supplies approximately 25-35% of the left ventricle.

Question 35

What are the high-risk segments in terms of coronary artery anatomy?

Answer 35

The left main stem and the proximal left anterior descending artery are considered high-risk segments due to their critical role in supplying a large portion of the left ventricle.

Question 36

What is coronary artery bypass grafting (CABG)?

Answer 36

CABG is an open-heart surgery performed through sternotomy. It involves using conduits (blood vessels) such as internal mammary arteries, radial arteries, and saphenous veins to bypass coronary artery stenoses. During the procedure, the heart is stopped, and a bypass machine maintains circulation. Recovery typically involves one week in the hospital and a recovery period of 2-4 months.

Question 37

What is percutaneous coronary intervention (PCI)?

Answer 37

PCI, also known as stenting or angioplasty, is a minimally invasive procedure. It involves accessing the coronary artery using a catheter, passing a wire through the narrowing, dilating the artery with a balloon, and deploying a stent. Local anesthesia is typically used, and recovery is rapid, with the patient often returning home on the same day and resuming normal activities within a week.

Question 38

When does myocardial necrosis become detectable in acute MI?

Answer 38

Myocardial necrosis becomes detectable after approximately 15 minutes of coronary occlusion. However, the distribution of necrosis within the ischemic territory is not uniform, with the sub-endocardial myocardium being more sensitive. Collateral blood vessels can provide partial protection.

Question 39

What is the time window for salvaging myocardium in acute MI?

Answer 39

Myocardium can be salvaged up to 12 hours after coronary occlusion, emphasizing the importance of prompt reperfusion therapy.

Question 40

What are the mortality rates associated with different reperfusion strategies for STEMI?

Answer 40

Pre-intervention: 10-15%
Thrombolysis/aspirin: 6-8%
Balloon-only PCI: 2-3%
Balloon + stenting PCI: <1%