Ischemic Heart Disease

Question 1

What is Ischemic Heart Disease?

Answer 1

imbalance between the myocardial blood flow and the metabolic demand of the myocardium

Question 2

Coronary artery perfusion depends upon

Answer 2

ostia (aortic diastolic pressure) Minus coronary sinus (right atrial pressure).

Question 3

Coronary blood flow is reduced during systole because of

Answer 3

Venturi effects at the coronary orifices and compression of intramuscular arteries during ventricular contraction.

Question 4

Factors reducing coronary blood flow include:

Answer 4

1. Decreased aortic diastolic pressure
2. Increased intraventricular pressure and myocardial contraction
3. Coronary artery stenosis
4. Aortic valve stenosis and regurgitation
5. Increased RA pressure

Question 5

collateral vessels are present in all hearts that measure ?

Answer 5

40 microns

Question 6

the cross-sectional area of the coronary artery lumen must be reduced by _____ to significantly affect perfusion.

Answer 6

> 75%

Question 7

“Thrombolytic therapy” with agents such as streptokinase or tissue plasminogen activatorS (TPA) such as atelpase is often used within

Answer 7

first 12 hours following onset of symptoms and with ST-segment elevation to try and lyse a recently formed thrombus.

Question 8

there is no ST-segment change and there is not sufficient myocardial damage for for release of a biomarker such as the troponins or CK-MB. There is one or more of the following:

(1) rest angina,
(2) new-onset severe angina, &
(3) a crescendo pattern of occurrence

Answer 8

1. Unstable angina:

Question 9

there is no ST-segment change but there is myocardial necrosis for release of a biomarker such as the troponins or CK-MB.

Answer 9

2. Non-ST-segment Elevation Myocardial Infarction (NSTEMI)

Question 10

there is ST-segment elevation and myocardial necrosis with release of a biomarker such as the troponins or CK-MB.

Answer 10

3. ST-segment Elevation Myocardial Infarction (STEMI)

Question 11

In 2000, the European Society of Cardiology and the American College of Cardiology Consensus group redefined myocardial infarction, with the definition being based on

Answer 11

myocyte necrosis as determined by troponins in the clinical setting of ischaemia

Question 12

The molecular events during MI relate to the initial ischemic event, reperfusion, and subsequent inflammatory response. Up to 6 hours following the initial ischemic event, most cell loss occur via

Answer 12

apoptosis. After that, necrosis predominates

Question 13

Transmural infarct involves

Answer 13

the entire thickness of the left ventricular wall from endocardium to epicardium, usually the anterior free wall and posterior free wall and septum with extension into the RV wall in 15-30%.

Question 14

Subendocardial infarct involves

Answer 14

multifocal areas of necrosis confined to the inner 1/3-1/2 of the left ventricular wall

Question 15

Ischemic Cardiomyopathy

Answer 15

disease results from severe coronary atherosclerosis involving all major branches. The result is an inadequate vascular supply which leads to myocyte loss. The myocyte loss coupled with fibrosis in the form of interstitial collagen deposition results in decreased compliance, which along with the accompanying cardiac dilation, results in overload of remaining myocytes. This keeps the process going, with compensation by continuing myocyte hypertrophy. There may even be compensation through hyperplasia as well as hypertrophy, which can explain the enormous size (2 to 3 times normal size) of the resulting heart. Eventually, the heart can no longer compensate, and cardiac failure ensues with arrhythmias and/or ischemic events.

Question 16

B-type natriuretic peptide (BNP)

Answer 16

released from ventricular myocardium. BNP release can be stimulated by systolic and diastolic left ventricular dysfunction, acute coronary syndromes, stable coronary heart disease, valvular heart disease, acute and chronic right ventricular failure, and left and right ventricular hypertrophy secondary to arterial or pulmonary hypertension. BNP is a marker for heart failure.

Question 17

C-reactive protein (CRP)

Answer 17

is an acute phase protein elevated when inflammation is present. Since inflammation is part of atheroma formation, then CRP may reflect the extent of atheromatous plaque formation and predict risk for acute coronary events. However, CRP lacks specificity for vascular events.