In coronary artery disease, the coronary arteries become narrowed or blocked by a gradual buildup of fat (cholesterol) within the artery wall, which reduces the blood flow to the heart muscle. This buildup is called "atherosclerotic plaque" or simply "plaque," and may start slowly progressing in childhood.
If the plaque narrows the channel of the artery, it may make it difficult for adequate quantities of blood to flow to the heart. Basically, there are three main coronary arteries in your heart. These arteries are located in the front of the heart (LAD), in the back of the heart (CIRC), and on the right side of the heart (RCA). One, two, or all three of these coronary arteries or their branches may be involved in the process of narrowing or blockage. The blockage may be partial or complete (see figures to the left). When a coronary artery becomes becomes partially or completely blocked, the part of the heart muscle supplied by the blood vessel does not get its required blood supply.
The first symptom generally is chest pain or chest discomfort which may be described as a pressure or heaviness beneath the breastbone (sternum) with associated neck, jaw or arm discomfort. Women often report different symptoms including back pain and nausea. The pattern varies from patient to patient and may have associated symptoms of sweating, shortness of breath, or nausea. This group of symptoms is referred to as angina. Angina is commonly brought on by physical work, mental work or stress, but may come on at rest or even while sleeping at night. Angina may be improved with the use of NTG (nitroglycerine), which helps the heart cope with these partial blockages.
If the blood supply to the blockage is not corrected rapidly, you may develop a "heart attack" (myocardial infarction). The area of the, heart muscle not receiving the blood supply will become scar tissue and will lose its ability to pump.
If your cardiologist has found coronary artery blockages during your catheterization, they may recommended stents, angioplasty or coronary artery bypass surgery to protect your heart muscle from these threatening blockages.
There are two main causes of clogged coronary arteries:
Coronary Artery Disease
Also referred to as atherosclerosis, is a gradual process in which fatty layers (plaque) build up on the inside of the arterial walls. As the plaque continues to build up and the artery narrows, there is less room for adequate blood flow.
Is a blood clot that lodges inside a coronary artery and prevents the flow of blood.
Angina vs. Heart Attack
Angina (chest pain) is not a heart attack, but may be a warning of an impending heart attack. Angina also occurs when the heart muscle is not receiving enough oxygen. With angina, however, no permanent damage is done to the heart muscle.
Angina is most commonly experienced with an activity such as shoveling snow, walking upstairs or uphill, consuming a large meal, or a stressful event. The symptoms of angina are similar to those of a heart attack. They are most commonly described as a squeezing, burning, tightness, fullness, or pressure across the chest. This discomfort may radiate to the shoulder, arms (especially the left), neck, jaw, teeth, earlobes, as well as the upper back between the shoulder blades. Numbness or tingling in the arms or hands may occur. Angina can be mistaken for indigestion.
Unlike a heart attack, angina may be relieved by rest and/or nitroglycerin within 15 minutes.
How is a Heart Attack Diagnosed?
Your physician has several tests at his/her disposal when determining whether or not you have had a heart attack.
Medical History and Physician Exam
Your physician will need to obtain your medical history and perform a complete physical examination. There will be questions asked regarding your present state of health, including specific symptoms you are experiencing. Questions concerning your lifestyle also need to be answered, i.e. dietary habits, exercise routine, stress, smoking history, alcohol consumption, and medications. It is important for your physician to know your family's medical history as well.
12 Lead Electrocardiogram (EKG)
An electrocardiogram records the electrical activity of your heart. A series of EKGs are taken during your hospitalization to observe the gradual changes which are indicative of a heart attack.
Cardiac enzymes are normally stored in the cells of the heart muscle. When the heart is injured, cardiac enzymes are released into the blood stream. A series of blood tests are drawn in order to observe changes of each specific enzyme.
Test & Procedures
In thrombolytic therapy, medication is given intravenously to dissolve the blood clot causing the heart attack. Once the blood clot is dissolved, blood flow can be restored to the affected area of the heart. Activase (t-PA) or Streptokinase are the most common medications used for dissolving a blood clot.
Cardiac Catheterization (coronary angiography)
A cardiac catheterization is an invasive procedure performed in a special lab under a local anesthetic and sterile conditions. A catheter is introduced into the heart via an artery and/or vein located in the groin or arm. Dye is injected through the catheter into the coronary arteries and/or heart's chambers, while an x-ray is taken and recorded on film. This procedure allows the physician to visualize the coronary arteries, as well as the function of the heart and its valves.
An echocardiogram is a non-invasive procedure using ultrasound waves to visualize the structures of the heart on the screen with the use of a probe. The hand-held probe is moved across the chest to visualize the movements of the heart’s valves and chambers.
Southwest Cardiovascular is accredited by the Intersocietal Commission for the Accreditation of Echocardiography Laboratories.
Also known as ultrasonic cardiography is an echocardiogram or "echo" is an ultrasound image of the heart. Our highly qualified Technician uses our state of the art machine to meticulously evaluate the structures inside the heart, the shape and measure of the chambers, the heart valves, the ejection fraction of the valves and the motion of the heart and valves. Any abnormalities are quantified and noted. The doctor uses this information to determine the proper function of the heart and the information can be used to evaluate which medications can be used most effectively to support the heart function best for the patient.
Bubble studies are a means of identifying an opening between in the septal wall, the heart structure between the atria. This opening, called a Patent Foramen Ovale or PFO, is quite common and about one in five people have this defect. This defect is most often treated medically but, in some cases, it may require other treatment as the blood that passes between the atrium in this way has bypassed the body’s natural filtration system and so debris, such as small blood clots, can pass through the body and lodge causing Transient Ischemic Attacks, or TIAs. (this should have a link)
Graded Exercise Stress Test
A graded exercise stress test involves exercising on a treadmill or bike at increased degrees of difficulty while the heart's response is recorded on an electrocardiogram (EKG). The level of exercise tolerance is measured by changes on the EKG, reported symptoms, as well as blood pressure and heart rate response. It also allows the physician to evaluate the effectiveness of your medical treatment. Patients recovering from a heart attack are usually given a low level exercise stress test prior to discharge.
A stress echocardiogram is similar to a graded exercise stress test, except that an echocardiogram is performed prior to the stress test and immediately following the stress test. A stress echocardiogram allows the physician to visualize changes in the pumping action of the heart between rest and exercise.
Holter and Event Monitoring
These are devices that provide important feedback for the doctor regarding the electrical functioning of the heart. The Holter monitor is worn for a twenty-four hour period of time and is used to detect frequently experienced, i.e. at least once a day, phenomena or irregularities.
Event monitors can be worn for up to thirty days. These monitors start recording at the patient’s indication when the heart’s patient experiences discomfort or some other irregularity. Event monitors are used when the doctor suspects an infrequently experienced arrhythmia.
Percutaneous Transluminal Coronary Angioplasty is the revascularization of the lumen or artery in a region of narrowing due to plaque or atherosclerosis. First developed by Andreas Grünzig in Switzerland, a small balloon is inserted into the artery over a wire from (usually) the femoral artery in the groin area. The balloon is inflated at pressures over 1 atm. for a period of seconds to dilate the affected region of the artery to it’s original diameter. Directional Coronary Atherectomy (DCA)
A directional coronary atherectomy is similar to an angioplasty except that the blockage is decreased by mechanically removing the plaque.
A stent is a tiny metal scaffold or mesh that is used to re-open or revascularize an artery. Stents can be bare metal or coated in with a medicine that helps reduce the occurrence of restenosis* – the rebuilding of plaque in the artery causing the reoccurrence of reduced or blockage of blood flow. The latter type of stent is known by the acronym of DES: Drug Eluting Stent. The stent is moved into place via a wire through the catheter that was inserted in the (usually) groin. The stent is then deployed by the inflation of the balloon upon which the stent sits. The balloon is inflated sufficiently to open the artery to (approximately) its original diameter – if achievable. The placement of a stent is a permanent placement. The decision to place a stent is based on the observations made during the angiogram or cardiac catheterization and, if used, IVUS. In general stents are placed if the artery is obstructed by 70% or greater.
* Restenosis is the recurrent narrowing due to the rebuilding of plaquie or scar tissue in the artery.
Coronary Artery Bypass Surgery (CABG)
A CABG is a surgical procedure that involves the removal of a portion of vein from the leg or the internal mammary artery (located in the chest) and using it to "bypass" the blockage(s) in the coronary artery.