All hearts occasionally miss a beat. The syncopation of a love struck heart is usually harmless. So is the heart's momentarily offbeat reaction to exertion or fatigue. But, when the tempo speeds up or slows down immoderately, or becomes markedly uneven, it can be potentially dangerous. The condition is called arrhythmia, which is the focus of electrophysiology, a subspeciality in the field of cardiology.

Arrhythmias can be slower or faster than the normal heart rate. Bradycardia, a heart rhythm of less than 60 beats a minute, may be the result of age and activity rather than disease, but can cause fatigue, dizziness, lightheadedness or fainting. An electronic pacemaker can correct the problem and bring the heartbeat up to speed. Tachycardia is an arrhyth-mia associated with an abnormally fast heart rate of 100 to 400 beats per minute that occurs when part of the heart spontaneously begins beating at a rate too fast to permit natural blood flow into either the upper or lower heart chambers. Some arrhythmias lead to the unexpected occurrence of sudden cardiac death.

Having an echocardiogram is a simple procedure that usually takes no more than an hour. The non-invasive, non-radioactive test uses painless sound waves to reveal structures and activity in the heart. A gel that can conduct sound waves is applied to the area of the chest above the heart, and a transducer -a piece of equipment able to direct the high-frequency emissions into the chest cavity -is placed over the gel. As they ricochet around the heart, the sound waves create echoes that are transmitted to the echocardiogram machine where the information is transformed into images.

The commonest symptom of coronary heart disease is angina pectoris. It is often recognized by a crushing chest pain that may radiate to the neck, jaw, back and left arm, but can also start with only a slight pressure in the chest. It is a sign that the heart muscle is getting too little blood when physi-cal effort or strong emotion make it work harder than usual. Angina was first described by William Heberden, an 18th-century physician and scholar who counted Benjamin Franklin and Samuel Johnson among his acquaintances and collaborators. Heberden also distinguished between smallpox and chicken pox and recognized night blindness as a medical problem, but is best remembered for his vividly accurate account of angina. Patients, he said, "are seized while they are walking with a painful and most disagreeable sensation in the breast . . . but the moment they stand still, all this uneasiness vanishes."

Angina is recurring pain or discomfort in the chest that happens when some part of the heart does not receive enough blood. It occurs when vessels that carry blood to the heart become narrowed and blocked due to atherosclerosis.

Angina feels like a pressing or squeezing pain, usually in the chest under the breast bone, but sometimes in the shoulders, arms, neck, jaws, or back. Angina is usually precipitated by exertion. It is usually relieved within a few minutes by resting or by taking prescribed angina medicine.

Angina occur when the heart's need for oxygen increases beyond the oxygen available to the heart. Physical exertion is the most common trigger for angina. Other triggers can be emotional stress, extreme cold or heat, heavy meals, alcohol, and cigarette smoking.

An episode of angina is not a heart attack. Angina pain means that some of the heart muscle in not getting enough blood temporarily--for example, during exercise, when the heart has to work harder. The pain does not mean that the heart muscle is suffering irreversible, permanent damage. Episodes of angina seldom cause permanent damage to heart muscle.

In contrast, a heart attack occurs when the blood flow to a part of the heart is suddenly and permanently cut off. This causes permanent damage to the heart muscle. Typically, the chest pain is more severe, lasts longer, and does not go away with rest or with medicine that was previously effective. It may be accompanied by indigestion, nausea, weakness, and sweating. However, the symptoms of a heart attack are varied and may be considerably milder.

When someone has a repeating but stable pattern of angina, an episode of angina does not mean that a heart attack is about to happen. Angina means that there is underlying coronary artery disease. Patients with angina are atan increased risk of heart attack compared with those who have no symptoms of cardiovascular disease, but the episode of angina is not a signal that a heart attack is about to happen. In contrast, when the pattern of angina changes--if episodes become more frequent, last longer, or occur without exercise--the risk of heart attack in subsequent days or weeks is much higher.

A person who has angina should learn the pattern of his or her angina--what causes an angina attack, what it feels like, how long episodes usually last, and whether medication relieves the attack. If the pattern changes sharply or if the symptoms are those of a heart attack, one should get medical help immediately, perhaps best done by seeking an evaluation at a nearby hospital emergency room.

No, not at all. Not all chest pain is from the heart, and not all pain from the heart is angina. For example, if the pain lasts for less that 30 seconds or if it goes away during a deep breath, after drinking a glass of water, or by changing position, it almost certainly is NOT angina and should not cause concern. But prolonged pain, unrelieved by rest and accompanied by other symptoms may signal a heart attack.

Usually the doctor can diagnose angina by noting the symptoms and how they arise. However one or more diagnostic tests may be needed to exclude angina or to establish the severity of the underlying coronary artery disease. These include the electrocardiogram (ECG) at rest, the stress test, and x- rays of the coronary arteries (coronary "arteriogram" or "angiogram").

For many patients with angina, the ECG at rest is normal. This is not surprising because the symptoms of angina occur during stress. Therefore, the functioning of the heart may be tested under stress, typically exercise. In the simplest stress test, the ECG is taken before, during, and after exercise to look for stress related abnormalities. Blood pressure is also measured during the stress test and symptoms are noted.

A more complex stress test involves picturing the blood flow pattern in the heart muscle during peak exercise and after rest. A tiny amount of a radioisotope, usually thallium, is injected into a vein at peak exercise and is taken up by normal heart muscle. A radioactivity detector and computer record the pattern of radioactivity distribution to various parts of the heart muscle. Regional differences in radioisotope concentration and in the rates at which the radioisotopes disappear are measures of unequal blood flow due to coronary artery narrowing, or due to failure of uptake in scarred heart muscle.

The most accurate way to assess the presence and severity of coronary disease is a coronary angiogram, an x-ray of the coronary artery. A long thin flexible tube (a "catheter") is threaded into an artery in the groin or forearm and advanced through the arterial system into one of the two major coronary arteries. A fluid that blocks x-rays (a "contrast medium" or "dye") is injected. X-rays of its distribution show the coronary arteries and their narrowing.

Angiography is an x-ray test of arteries (blood vessels). It can be used to look at the arteries throughout the whole body. An interventional radiologist, who is a specially trained doctor, performs this x-ray procedure. During the test, the radiologist places a catheter (a small tube) into one of the arteries and injects contrast (x-ray dye) into the vessel and takes x-rays of that area. The contrast makes the artery visible on the x-rays. With the help of this test other doctors can plan the best treatment.

One of the most common reasons for needing an angiogram is having symptoms that suggest blockage of an artery. There are many examples of this. A blocked artery in the heart (coronary artery) when gives rise to pain. A blocked artery in the leg may cause pain in the your leg when you walk. Blocked arteries to the brain may cause vision problems and weakness, and blocked kidneys arteries may cause high blood pressure. This test can identify the exact location where the artery is blocked, if it is severe, and what is causing the blockage.

The underlying coronary artery disease that causes angina should be attacked by controlling existing "risk factors." These include high blood pressure, cigarette smoking, high blood cholesterol levels, and excess weight. If the doctor has prescribed a drug to lower blood pressure, it should be taken as directed. Advice is available on how to eat to control weight, blood cholesterol levels, and blood pressure. A physician can also help patients to stop smoking. Taking these steps reduces the likelihood that coronary artery disease will lead to a heart attack.

Most people with angina learn to adjust their lives to minimize episodes of angina, by taking sensible precautions and using medications if necessary.

Usually the first line of defense involves changing one's living habits to avoid bringing on attacks of angina. Controlling physical activity, adopting good eating habits, moderating alcohol consumption, and not smoking are some of the precautions that can help patients live more comfortably and with less angina. For example, if angina comes on with strenuous exercise, exercise a little less strenuously, but do exercise. If angina occurs after heavy meals, avoid large meals and rich foods that leave one feeling stuffed. Controlling weight, reducing the amount of fat in the diet, and avoiding emotional upsets may also help.

Angina is often controlled by drugs. The most commonly prescribed drug for angina is nitroglycerin, which relieves pain by widening blood vessels. This allows more blood to flow to the heart muscle and also decreases the work load of the heart. Nitroglycerin is taken when discomfort occurs or is expected. Doctors frequently prescribe other drugs, to be taken regularly, that reduce the heart's workload. Beta blockers slow the heart rate and lessen the force of the heart muscle contraction. Calcium channel blockers are also effective in reducing the frequency and severity of angina attacks.

Doctors may recommend surgery or angioplasty if drugs fail to ease angina or if the risk of heart attack is high. Coronary artery bypass surgery is an operation in which a blood vessel is grafted onto the blocked artery to bypass the blocked or diseased section so that blood can get to the heart muscle. An artery from inside the chest (an "internal mammary" graft) or long vein from the leg (a "saphenous vein" graft) may be used.

Yes. It is important to work with the doctor to develop an exercise plan. Exercise may increase the level of pain-free activity, relieve stress, improve the heart's blood supply, and help control weight. A person with angina should start an exercise program only with the doctor's advice. Many doctors tell angina patients to gradually build up their fitness level--for example, start with a 5-minute walk and increase over weeks or months to 30 minutes or 1 hour. The idea is to gradually increase stamina by working at a steady pace, but avoiding sudden bursts of effort.

Angioplasty is a procedure for treating coronary arteries that are dangerously narrowed or clogged. When atherosclerosis forms, slowing or stopping blood flow to the heart, the heart's muscle wall is deprived of oxygen, a condition known as ischemia, which can lead to the death of heart cells and heart patients. To clear the blockage as thoroughly as possible, interventional cardiologists insert a catheter into the patient's arm or leg that carries devices into the constrict-ed artery to reopen it. The most familiar catheterization procedure today places either a stent or a tiny inflatable balloon inside the artery walls to reduce plaque by flattening and friction. Other catheter technology can laser, cut, or drill out the disabling substance.

When the first coronary angioplasty (also called percutaneous transluminal coronary angioplasty or PTCA) was performed in 1977, the only device available to treat a blockage in a coronary artery was a small inflatable balloon. As a result, people began referring to angioplasty as the "balloon procedure." Over the last decade, new devices that can cut out pieces of a plaque, vaporize it with a laser, bore out the blockage with a kind of surgical drill bit, or insert a tiny metal spring into the coronary artery to help keep it stretched open have been developed. While the term "coronary angioplasty" technically refers only to the use of an inflatable balloon to treat a blockage in the coronary artery, doctors now use the term to refer to procedures that treat a coronary blockage via insertion through an artery in the groin.

There are several reasons to undergo an angioplasty procedure. If chest pain symptoms are not easily controlled with medications, or if symptoms prevent the patient from participating in daily activities, an angioplasty may decrease or eliminate the chest pains. After the procedure, fewer cardiac medications may be required. If the patient is experiencing chest pains at rest (i.e., without exercise or exertion), or if chest pain continues after a heart attack, an angioplasty procedure is used to treat the blockage causing the problem. One recently completed study found that in certain male patients with chest pains at rest, including those who had suffered a small heart attack, treatment of coronary stenoses with an angioplasty procedure resulted in fewer long-term adverse events than treatment with medications alone.

However, not everyone with coronary artery disease needs an angioplasty procedure. Some patients with infrequent or rare angina or those whose symptoms are easily controlled with medications can be treated with medication alone and may not require angioplasty. There is, at present, no conclusive data to prove that blockages that are "incidentally" discovered need to be treated with an angioplasty procedure. Additionally, angioplasty is associated with a small risk for complications. Although angioplasty, particularly in the age of coronary stenting, has proven to be an excellent treatment for patients with significant chest pain, there should be a sound medical reason for angioplasty.

Arteriosclerosis is the general term for thickening of the arteries, a condition that, to a greater or lesser degree, comes naturally with age. It is a silent occurrence, usually discovered only after a cardiovascular problem devel-ops. A particular kind of arteriosclerosis is atherosclerosis, a name taken from the Greek for gruel or paste (athero) and hardness (sclerosis). It is a progressive disease caused by plaque, the fatty deposits of cholesterol, cell waste, calcium and fibrin that form clots inside the arteries and can block blood flow, causing a heart attack or stroke. High blood pressure, cigarette smoke and high cholesterol all contribute to intensifying atherosclerosis.

A Coronary Artery Bypass Graft (CABG) is performed to relieve ischaemia by providing improved myocardial perfusion beyond areas of coronary stenosis. There are several factors that should be evaluated in any patient being considered for surgery. These include an assessment of the degree of anginal symptoms and the presence of associated medical problems, a determination of the physiologic significance of the CAD, documented action of angiography abnormalities of coronary arteries, and an assessment of left ventricular function. To better understand CABG, other key elements also need to be analyzed. These include indications of CABG, risk factors associated with CABG, and the surgical procedure itself.

CABG surgery is an alternative to drug therapy and other less invasive techniques such as percutaneous transluminal coronary angioplasty (PTCA), atherectomay, and laser therapy. CABG therapy is indicated in patients who have left main coronary artery disease or disease affecting three or more blood vessels. Surgery is also indicated when a patient has at least 60% stenosis of the coronary arteries.

If the patient has multiple medical problems, such as diabetes, recent stroke, and lung or renal disease, or ejection fraction of less than 20%, they are considered a high-risk patient. Surgery may also be more technically difficult if the patient's coronary arteries are small or if they have diffuse coronary artery disease. The typical CABG patient is generally a high-risk patient, as low-risk patients are frequent candidates for percutaneous cardiac procedures such as angioplasty, atherectomy, and stenting.

The Principle

What do you do when you come across a blocked highway ? Take a detour, of course. One which connects back to the highway beyond the area that is blocked. The CABG operation does the same on the "highway" of the blood stream. When a coronary artery is obstructed, the CABG operation provides a detour by connecting the aorta on one end to the coronary artery beyond the area of obstruction - by interposing a tube or "conduit" which may be a piece of artery or vein.

The Technique:

CABG is an OPEN HEART OPERARTION that is, one which is done with the patient hooked on to a artificial heart-lung machine while the heart is stopped and operated on. The conduit which is a portion of vein or artery from another part of the body is first prepared for use.

The diseased coronary artery is then identified and an opening made on it beyond the area of obstruction. The surgeon, using magnifying loops that make the field of operation appear thrice as large, then sutures the conduit to this opening on the coronary artery using special thread that is as fine as a strand of hair, and tremendously strong. Consider that the average coronary artery is only around 3 millimeters in size and now you can truly appreciate the technical skill and delicacy needed to execute this complex operation.

The other end of the conduit is then sutured on to the aorta itself. The procedure is repeated on all the coronary artery branches that are significantly diseased.

This in brief is what a CABG operation is all about. There are numerous technical variations of this procedure.

Minimally invasive bypass (also called buttonhole or keyhole bypass) surgeries are exciting advances in basic bypass surgery that are currently being done with good success for patients with disease in single vessels. One uses a four-inch incision, and the surgeon works on the front of the heart while it is beating slowly. It is used just for bypasses with one or two arteries.

In another, the heart is stopped, and the patient is put on a machine that reroutes the blood through a device that keeps it oxygenated. Fiberoptic scopes and instruments are passed through a number of finger-sized incisions and the surgeon works on all sides of the heart guided by a video image from a tiny camera inserted through a four-inch incision.

Some advanced heart centers now employ robotic systems, which allow the surgeon to perform extremely delicate maneuvers on tiny vessels through pencil-size incisions. They are not yet used for the whole bypass process.

Early results show that minimally invasive bypass procedures will be less expensive, require a shorter hospital stay, and be a significant improvement over conventional coronary artery bypass surgery.

Coronary artery disease (CAD) is caused by a narrowing or constriction of the arteries that supply the heart muscle itself with blood. This narrowing is a result of atherosclerosis-the buildup of cholesterol and other fatty substances in the arteries. When the arteries narrow, blood flow is reduced. The reduced blood flow (ischemia) causes the heart muscle to receive less oxygen in certain areas. If the blood flow is completely cut off, a heart attack (myocardial infarction) will occur, and the heart muscle will be permanently damaged.

PET : Supercharged Imaging Positron Emission Tomography (PET) is an imaging technology. Radioactive particles called isotopes are injected into the blood stream of patients undergoing a PET exam. The energy which is discharged following collision between the PET “antimatter” radiotracer and subatomic particles in the heart tissue provides information used to create extremely accurate three-dimensional and cross-sectional computer images of the blood flow and metabolism of the heart. PET’s ability to visualize these functions with unprecedented precision has been compared to holding the human heart in one’s hand while examining its interior as it is functioning