- While the heart pumps freshly-oxygenated blood to the rest of the body, it too needs fresh blood in order to function. It is supplied by blood vessels called the coronary arteries.
- On the left side of the heart, there is the left mainstem artery, which quickly branches into the left anterior descending artery (LAD), and the circumflex (Cx).
- The major artery on the right side is the right coronary artery (RCA).
- If the artery walls thicken, the artery canals narrow, thus decreasing the amount of blood that can flow through them. This, in turn, compromises the blood supply to the heart.
- We still don't fully understand why arteriosclerosis occurs, but it is clear that that inner lining of the artery walls may be damaged by multiple factors. These include elevated LDL cholesterol, decreased HDL cholesterol, High Blood Pressure, smoking (especially cigarettes), and Diabetes Mellitus.
- This damage leads to an abnormal reaction of platelets and blood monocytes with the inner wall. This, in turn, leads to the deposition of abnormal fat, cells, and debris into the inner wall of the arteries (known as arteriosclerosis, literally "hardening" of the arteries). Consequently, there may be one or more areas of narrowing in a given coronary blood vessel.
- With progressive narrowing of the
coronary blood vessels, the heart itself fails to get enough
oxygenated blood. This translates into such symptoms as
chest pain, shortness of breath, nausea, left arm pain, or
fatigue on exercise (this is known as angina*). As it progresses, even mild exertion may cause angina symptoms.
- If the oxygen demand is greater
than these narrowed vessels can deliver, myocardial
infarction** (heart attack) occurs. Additionally, a blood clot is more likely to occur in the area of narrowing. When this happens, blood flow is completely shut off in the artery, resulting in Myocardial Infarction.
- Angina means the heart muscle is temporarily not getting enough oxygenated blood, but no permanent heart damage has occurred
- Myocardial Infarction (heart
attack) means there has been permanent (irreversible) damage
to part of the heart
- Chest pain (initially on exertion)
- Shortness of breath on exertion
- Left arm pain on exertion
- Fatigue on exertion
- Nausea on exertion
- Chest pain -- may feel pressure in the middle of the chest, crushing sensation, feel like chest being sat on
- Shortness of breath
- Clamminess to the skin
- Break into a sweat (diaphoresis)
- Left arm pain
- Neck exam may reveal carotid bruits
- Heart exam may be normal, have irregular beats such as ventricular tachycardia, atrial fibrillation, or PVCs. Murmur such as Mitral Regurgitation may be present
- Lung exam may show evidence of Heart Failure
during a heart attack (crackles, wheezes)
- EKG shows characteristic ST elevations or T wave inversions of a heart attack. It may also show evidence of an old heart attack, i.e. Q waves or poor R wave progression.
- Blood tests during a heart attack will show elevated Creatinine kinase (CK), Troponin level, or LDL level.
- Stress (treadmill) test will be performed if this condition is suspected. A stress test involves exercising on a treadmill while connected to an EKG machine. If ischemia (heart blockage) is present, the EKG appears abnormal (usually ST Depression). Additionally, either a nuclear medicine test (injected thallium or Cardiolyte) or Echocardiogram is often performed simultaneously with the treadmill stress test in those patients in whom the suspicion for coronary artery disease is high. This allows us to take a picture of the heart muscle's response to exercise. (It is of note that a plain treadmill stress test in women can give misleading results, and especially in those with a higher suspicion of heart disease, making a stress Echocardiogram or stress Cardiolyte/Thallium a necessary adjunct).
- Echocardiogram --
this is an Ultrasound test of the heart and shows function of the heart muscle at rest, and heart valve function. Routine Echocardiograms show evidence of previous heart attacks.
- Stress Cardiolyte or stress thallium test -- this is a stress treadmill test combined with Cardiolyte or Thallium injection (described above). It is about 90% sensitive for detecting heart disease.
- Stress Echocardiogram --
this is where stress treadmill is combined with Echocardiogram before and after exercise. It is also about 90% sensitive for detecting heart disease.
- Ultra-fast CAT scanning -- this is a new (and somewhat controversial) technique, involving the scanning of coronary blood vessels, and assessment for Calcium levels. This in turn correlates with the degree of blockage of the arteries. The problem with this test is that it does not clearly correlate into how to manage abnormalities. If this test comes back with little or no Calcium build up, it is probably a good indication of the absence of heart disease. If it comes back in the intermediate range, it makes it hard to decide whether to do more invasive testing.
- Cardiac catheterization -- this is the gold standard. A wire is passed through a catheter into the blood vessels of the heart. Then dye is injected and X-Rays of the heart
visualized. This allows for exact determination of
blockages. Heart function and valve function may also be
assessed at the same
- Family history
- Being male
- Age greater than 50 years old
- Elevated LDL cholesterol ("bad" cholesterol)
- Low HDL cholesterol ("good" cholesterol)
- Smoking (especially cigarettes)
- Diabetes Mellitus
- Low estrogen level (e.g., post-menopausal women not on hormone replacement)
- Elevated blood homocystine level
- Hypertriglyceridemia (elevated fat level in blood) is most likely a risk factor
- Familial (genetic) hyperlipidemia
(disorders of fat and cholesterol
For acute treatment of myocardial
infarction (heart attack) see that section
- Noninvasive treatments:
- Beta-blocker medication (e.g. metoprolol)
- Nitrates (e.g. nitroglycerin patch, Sordid)
- Calcium channel blockers may be beneficial for some persons (e.g., Diltiazem)
- Cholesterol -- lowering medications, especially the "statins" such as Pravachol or Lipitor, may
- Angioplasty/stent placement --
during a cardiac catheterization a balloon catheter may be
placed in the area of blockage to "smash" the blockage
open (this is angioplasty). Alternatively, a stent device
may be placed in the blockage area to permanently open the
flow. This technique can be limited (not possible) if the
narrows are long, in difficult to reach places (such as
bifurcations, i.e., places where two arteries come
together), or if there are too many blockages.
- Coronary artery bypass graft
surgery (CABG) -- veins from the legs or arteries are used
to bypass blockages (the surgeon connects the vein/artery
to a point before the blockage and then bypasses (jumps
over) and connects it to a point past the blockage). This
is usually the best choice in three-vessel coronary heart
disease, or disease of the left main stem. In one- or
two-vessel disease, the decision to use CABG,
angioplasty/stenting, or medical management is usually
determined by the
- 50% of patients with diabetes
have minimal or no symptoms of angina or heart attack. This
means that diabetics may have a massive heart attack and
feel nothing! Up to 25% of patients without diabetes may
have minimal symptoms as well.
- Lipid profile (this includes total cholesterol, LDL, HDL, and triglyceride levels)
- Homocystine level -- this blood test seems to correlate with increased reactivity of the lining of the artery walls to atherosclerosis formation
- C-reactive protein -- this is an inflammatory marker.
This is useful for predicting which patients will respond
to aspirin as a preventative in the case of an ischemic
event, such as a heart attack.
- Preventive treatment
- Low fat, low cholesterol diet
- Proper aerobic exercise (even regular walking, e.g. 30 minutes continuously, four times a week, is effective)
- Quit or do not begin smoking
- Cholesterol-lowering medications especially the "statins" such as Pravachol or Lipitor if LDL is elevated (optimal LDL in those with established arteriosclerosis is 100 or less, and those without arteriosclerosis is 130 or less)
- If HDL (good cholesterol) is low,
the following may help:
- Red wine in moderation (one drink per night)
- Niacin given at prescription levels (this is a vitamin, but needs high specially prescribed doses to lower cholesterol)
- "Statins" such as Pravachol or Lipitor (not only
do they lower LDL, but they modestly raise HDL
- Elevated homocystine levels -- Folic Acid, which is a vitamin, will lower Homocystine levels. The usual dose is 800 to 1000 mcg per day. It must be taken with a B complex vitamin (or multivitamin) to be effective. Dietary sources of Folic Acid do not seem to be effective (e.g., leafy vegetables)
- Elevated C-reactive protein
-- aspirin from 81mg (baby aspirin) to 325 mg (whole adult aspirin) is effective
- High Blood Pressure should be properly controlled
- Blood sugar should be aggressively controlled in those with diabetes (though cautiously in those who are also on beta-blockers)
- Familial hyperlipidemic syndromes -- see this section
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