Cardiac Ischemia: Myocardial Oxygen Balance

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Questions and Answers

Which factor differentiates angina specifically from other conditions causing similar chest discomfort?

The location of the discomfort in the retrosternal area.
The presence of nausea during the episode.
The discomfort's relation specifically to myocardial oxygen imbalance. (correct)
The description of the sensation as a 'pressure' or 'tightness'.

What is the primary reason coronary perfusion mainly occurs during diastole rather than systole?

The aortic pressure is higher during diastole.
Systolic compression impairs flow in small coronary branches within the myocardium. (correct)
The heart's metabolic requirements are lower during diastole.
The oxygen content of blood is higher during diastole.

How does adenosine, a potent vasodilator, increase coronary blood flow?

By directly stimulating the release of nitric oxide from endothelial cells.
By increasing calcium entry into vascular smooth muscle cells.
By increasing the production of high-energy phosphates in the mitochondria.
By decreasing calcium entry into vascular smooth muscle cells, leading to relaxation. (correct)

In the context of myocardial oxygen demand, what is the most accurate description of ventricular wall stress?

The tangential force acting on myocardial fibers, tending to pull them apart. (C) Signup and view all the answers

According to Poiseuille's law, which variable has the most substantial impact on vascular resistance?

Vessel radius. (C) Signup and view all the answers

How does endothelial dysfunction contribute to reduced myocardial oxygen supply in chronic coronary artery disease?

Through inappropriate vasoconstriction of coronary arteries. (C) Signup and view all the answers

What is the underlying mechanism by which stable angina typically manifests?

Fixed, obstructive atheromatous plaque in one or more coronary arteries. (A) Signup and view all the answers

What is the primary characteristic of 'stunned myocardium' following an episode of ischemia?

Prolonged systolic dysfunction despite restored blood flow. (D) Signup and view all the answers

Which of the following best describes 'hibernating myocardium'?

Myocardial tissue with chronic contractile dysfunction due to persistently reduced blood supply. (C) Signup and view all the answers

Which symptom is most indicative of pulmonary congestion resulting from myocardial ischemia?

Dyspnea. (D) Signup and view all the answers

What key aspect of a patient's history is most critical in evaluating ischemic heart disease?

Description of chest discomfort and associated symptoms. (A) Signup and view all the answers

Which of the following is a typical description of angina pectoris?

Steady discomfort described as pressure or heaviness in the chest. (C) Signup and view all the answers

What physiological change explains why cold weather can precipitate angina in patients with CAD?

Peripheral vasoconstriction. (B) Signup and view all the answers

What is a key differentiating factor between angina and gastroesophageal reflux in recurrent chest pain?

The relationship to physical exertion. (C) Signup and view all the answers

What ECG change is typical of acute myocardial ischemia?

Transient horizontal or downsloping ST-segment depressions. (D) Signup and view all the answers

A stress test is considered markedly positive if a patient experiences which sign of severe ischemic heart disease?

Development of ischemic ECG changes in the first 3 minutes of exercise. (A) Signup and view all the answers

Why is a standard exercise test less useful in patients with baseline ST segment abnormalities?

It is difficult to interpret ischemia-related changes on the ECG. (B) Signup and view all the answers

Which method is used to differentiate between transient ischemia and infarcted tissue during myocardial perfusion imaging?

Performing imaging at rest and at peak exercise. (D) Signup and view all the answers

What is the primary mechanism by which adenosine and regadenoson induce coronary vasodilation in pharmacologic stress tests?

Binding to adenosine A2a receptors on vascular smooth muscle cells. (A) Signup and view all the answers

What is the most direct method for identifying coronary artery stenoses?

Coronary angiography. (C) Signup and view all the answers

Which FFR value is used when identifying stenoses that typically warrant mechanical intervention?

FFR values <0.80 (B) Signup and view all the answers

Which noninvasive cardiac test is the most useful for completely ruling out the presence of CAD?

Cardiac CT without contrast administration to measure coronary artery calcification. (D) Signup and view all the answers

A patient with chronic angina would receive which of the following recommendations?

Address modifiable risk factors of atherosclerosis. (B) Signup and view all the answers

What is the primary mechanism by which sublingual nitroglycerin relieves angina?

Reducing venous return to the heart. (A) Signup and view all the answers

What effect does slowing the heart rate have on myocardial oxygen supply?

Augments the time spent in diastole. (A) Signup and view all the answers

A patient with angina and underlying asthma requires what adjustments to their treatment plan?

Dobutamine pharmacologic testing is preferred. (D) Signup and view all the answers

Why is it usual to have a nitrate-free interval each day when receiving nitrate therapy?

Prevent the development of drug tolerance. (A) Signup and view all the answers

What distinguishes ranolazine from other anti-ischemic medications?

Does not affect the heart rate or blood pressure. (B) Signup and view all the answers

What is the mechanism of aspirin in preventing acute cardiac events?

Inhibiting platelet aggregation. (A) Signup and view all the answers

Which class of drugs has demonstrated a linear relationship between the magnitude of LDL cholesterol lowering and the relative reduction in cardiovascular risk?

HMG-CoA reductase inhibitors (statins). (D) Signup and view all the answers

What is a key consideration when prescribing antiplatelet agents after stent implantation?

Risk of thrombus formation. (A) Signup and view all the answers

When comparing CABG surgery to stenting with PCI, what vessel is typically grafted with the internal mammary artery?

Left anterior descending artery. (C) Signup and view all the answers

In assessing mortality, what is the comparison between off-pump CABG procedures compared with standard CABG?

Comparable mortality benefit. (C) Signup and view all the answers

In which group of patients, CABG would be the best option, compared to medical therapy, for survival benefit?

Those with diabetes and multivessel disease. (C) Signup and view all the answers

For which of the following patients is PCI a reasonable approach for myocardial revascularization?

Patients with high surgical risk, and less extensive disease. (A) Signup and view all the answers

What is the major benefit of percutaneous transluminal coronary angioplasty (PTCA)?

Reduction of the stenosis to increase lumen size. (C) Signup and view all the answers

What is the benefit for patients that receive drug-eluting stents

Preventing neointimal proliferation. (D) Signup and view all the answers

Flashcards

Ischemic heart disease

Condition where an imbalance between myocardial oxygen supply and demand results in myocardial hypoxia and waste build-up.

Angina pectoris

Uncomfortable sensation in the chest caused by myocardial ischemia.

Stable angina

Chronic angina pattern that is triggered by physical activity or emotional stress, and is relieved by rest.

Variant angina.

Angina discomfort usually occurs at rest, caused by coronary artery spasm rather than increased oxygen demand.