Patients with coronary artery blockages may have minimal symptoms and an unremarkable or unchanged EKG while at rest. However, symptoms and signs of heart disease may become unmasked by exposing the heart to the stress of exercise. During exercise, healthy coronary arteries dilate (develop a more open channel) than an artery that has a blockage. This unequal dilation causes more blood to be delivered to heart muscle supplied by the normal artery. In contrast, narrowed arteries end up supplying reduced flow to it's area of distribution. This reduced flow causes the involved muscle to "starve" during exercise(running, jogging, climbing, etc) . The "starvation" may produce symptoms (like chest discomfort or inappropriate shortness of breath), and the EKG may produce characteristic abnormalities. Most commonly, a motorized treadmill is used for exercise, while a stationary bicycle is used in some exercise laboratories. When is a Regular Stress Test ordered? A regular stress test is considered in the following circumstances:

Patients with symptoms or signs that are suggestive of coronary artery diseases (CAD). Patients with significant risk factors for CAD.

To evaluate exercise tolerance when patients have unexplained fatigue and shortness of breath.

To evaluate blood pressure response to exercise in patients with borderline hypertension.

To look for exercise-induced serious irregular heart beats. Please remember that the regular stress test is heavily dependent upon interpretation of EKG changes produced by exercise.

Preparing for the Regular Stress Test:

The following recommendations are "generic" for all types of cardiac stress tests: Do not eat or drink for three hours prior to the procedure. This reduces the likelihood of nausea that may accompany strenuous exercise after a heavy meal. Diabetics, particularly those who use insulin, will need special instructions from the physician's office. Specific heart medicines may need to be stopped one or two days prior to the test. Such instructions are generally provided when the test is scheduled. Wear comfortable clothing and shoes that are suitable for exercise. An explanation of the test is provided and the patient is asked to sign a consent form. How long does the entire test take? A patient should allow approximately one hour for the entire test, including the preparation.

The patient is brought to the exercise laboratory where the heart rate and blood pressure are recorded at rest. Sticky electrodes are attached to the chest, shoulders and hips and connected to the EKG portion of the Stress test machine. A 12-lead EKG is recorded on paper. Each lead of the EKG represents a different portion of the heart, with adjacent leads representing a single wall. For example:

Leads 2, 3, and aVF = bottom or inferior portion of the heart.

Leads V1 and V2 = septum or partition of the heart.

Leads V3, V4, V5 and V6 = anterior or front portion of the heart. Leads 1 and aVL = superior or top and outer left portion of the heart.

Lead aVR looks at the cavity of the heart and has almost no clinical value in identifying coronary disease.

Three of the EKG leads are also constantly displayed on the treadmill monitor. Each lead representing a different wall. The physician has the option of selecting different combinations of three.

The treadmill is then started at a relatively slow "warm-up" speed. The treadmill speed and it's slope or inclination are increased every three minutes according to a preprogrammed protocol (Bruce is the commonest protocol in the USA, but several other protocols are perfectly acceptable). The protocol dictates the precise speed and slope. Each three minute interval is known as a Stage (Stage 1, Stage 2, Stage 3, etc. Thus a patient completing Stage 3 has exercised for 3 x 3 = 9 minutes). The patient's blood pressure is usually recorded during the second minute of each Stage. However, it may be recorded more frequently if the readings are too high or too low. As noted earlier, the EKG is constantly displayed on the monitor. It is also recorded on paper at one minute intervals. The physician pays particular attention to the heart rate, blood pressure, changes in the EKG pattern, irregular heart rhythm, and the patient's appearance and symptoms. The treadmill is stopped when the patient achieves a target heart rate (this is 85% of the maximal heart rate predicted for the patient's age).

However, if the patient is doing extremely well at peak exercise, the treadmill test may be continued further. The test may be stopped prior to achievement of the target heart rate if the patient develops significant chest discomfort, shortness of breath, dizziness, unsteady gait, etc., or if the EKG shows alarming changes or serious irregular heart beats. It may also be stopped if the blood pressure (BP) rises or falls beyond acceptable limits. Please note that the systolic BP (upper number) may normally rise to 200 at peak exercise. At the same time, the diastolic BP (lower number) remains unchanged or falls to a slight degree. In contrast, the BP of patients with hypertension or high BP will show a rise of both systolic and diastolic readings. The latter may rise above 90 - 100.

This is a type of nuclear scanning test or myocardial perfusion (mi"o-KAR'de-al per-FU'zhun) imaging test. It shows how well blood flows to the heart muscle. It's usually done along with an exercise stress test on a treadmill or bicycle.

The thallium stress test is useful to determine:

- Extent of a coronary artery blockage

- Prognosis of patients who've suffered a heart attack

- Effectiveness of cardiac procedures done to improve circulation in coronary arteries

- Cause(s) of chest pain

- Level of exercise that a patient can safely perform

The first pictures are made shortly after the exercise test and show blood flow to the heart during exercise. The heart is "stressed" during the exercise test -- thus the name "stress test." The patient then lies quietly for 2-3 hours and another series of pictures is made. These show blood flow to the heart muscle during rest.

- If the test is normal during both exercise and rest, then blood flow through the coronary arteries is normal. The coronary arteries supply blood to the heart muscle.

- If the test shows that (or this, or whatever) perfusion (blood flow) is normal during rest but not during exercise (a perfusion defect), then the heart isn't getting enough blood when it must work harder than normal. This may be due to a blockage in one or more coronary arteries.

- If the test is abnormal during both exercise and rest, there's limited blood flow to that part of the heart at all times.

- If no thallium is seen in some part of the heart muscle, the cells in this part of the heart are dead from a prior heart attack. (They have become scar tissue.)

Sometimes you can't do an exercise test because you're too sick or have physical problems. In this case, a drug such as dipyridamole (di-pi-RID'ah-mol) or adenosine is given. This drug increases blood flow to the heart and thus "mimics" an exercise test. Then the thallium test is given.

Most people can raise their HDL (good cholesterol) levels by exercising, not smoking and staying at a healthy weight.

The symptoms of this new influenza A H1N1 virus in people are similar to the symptoms of regular human flu and include fever, cough, sore throat, body aches, headache, chills and fatigue. A significant number of people who have been infected with this virus also have reported diarrhea and vomiting. Also, like seasonal flu, severe illnesses and death has occurred as a result of illness associated with this virus.

Spread of this H1N1 virus is thought to be happening in the same way that seasonal flu spreads. Flu viruses are spread mainly from person to person through coughing or sneezing by people with influenza. Sometimes people may become infected by touching something with flu viruses on it and then touching their mouth or nose. No. H1N1 viruses are not spread by food. You cannot get this new HIN1 virus from eating pork or pork products. Eating properly handled and cooked pork products is safe

Recreational water that has been treated at CDC recommended disinfectant levels (1¡V3 parts per million [ppm or mg/L] for pools and 2¡V5 ppm for spas) does not likely pose a risk for transmission of influenza viruses. Currently, there are no documented human cases of influenza caused by exposure to influenza-contaminated swimming pool water. No research has been completed on the susceptibility of the novel H1N1 flu virus to chlorine and other disinfectants used in swimming pools, spas, water parks, interactive fountains, and other treated recreational venues. However, recent studies have demonstrated that free chlorine levels recommended by CDC are adequate to disinfect highly pathogenic H5N1 avian influenza virus. It is likely that other influenza viruses such as the novel H1N1 flu virus would also be disinfected by these chlorine levels.

Yes, recreational water venues are no different than any other group setting. The spread of this novel H1N1 flu is thought to be happening in the same way that seasonal flu spreads. Flu viruses are spread mainly from person to person through coughing or sneezing of people with influenza. Sometimes people may become infected by touching something with flu viruses on it and then touching their mouth or nose.

First and most important: wash your hands. Try to stay in good general health. Get plenty of sleep, be physically active, manage your stress, drink plenty of fluids, and eat nutritious food. Try not to touch surfaces that may be contaminated with the flu virus. Avoid close contact with people who are sick.

At the current time, CDC believes that this virus has the same properties in terms of spread as seasonal flu viruses. With seasonal flu, studies have shown that people may be contagious from one day before they develop symptoms to up to 7 days after they get sick. Children, especially younger children, might potentially be contagious for longer periods. CDC is studying the virus and its capabilities to try to learn more and will provide more information as it becomes available.

Germs can be spread when a person touches something that is contaminated with germs and then touches his or her eyes, nose, or mouth. Droplets from a cough or sneeze of an infected person move through the air. Germs can be spread when a person touches respiratory droplets from another person on a surface like a desk, for example, and then touches their own eyes, mouth or nose before washing their hands.

There is no vaccine available right now to protect against this new H1N1 virus. There are everyday actions that can help prevent the spread of germs that cause respiratory illnesses like influenza. Take these everyday steps to protect your health: „h Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it. „h Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hand cleaners are also effective. „h Avoid touching your eyes, nose or mouth. Germs spread this way. „h Try to avoid close contact with sick people. „h Stay home if you are sick for 7 days after your symptoms begin or until you have been symptom-free for 24 hours, whichever is longer. This is to keep from infecting others and spreading the virus further. Other important actions that you can take are: „h Follow public health advice regarding school closures, avoiding crowds and other social distancing measures. „h Be prepared in case you get sick and need to stay home for a week or so; a supply of over-the-counter medicines, alcohol-based hand rubs, tissues and other related items might could be useful and help avoid the need to make trips out in public while you are sick and contagious.

Washing your hands often will help protect you from germs. Wash with soap and water or clean with alcohol-based hand cleaner. We recommend that when you wash your hands -- with soap and warm water -- that you wash for 15 to 20 seconds. When soap and water are not available, alcohol-based disposable hand wipes or gel sanitizers may be used. You can find them in most supermarkets and drugstores. If using gel, rub your hands until the gel is dry. The gel doesn't need water to work; the alcohol in it kills the germs on your hands. Influenza virus is destroyed by heat (167-212¢XF [75-100¢XC]). In addition, several chemical germicides, including chlorine, hydrogen peroxide, detergents (soap), iodophors (iodine-based antiseptics), and alcohols are effective against human influenza viruses if used in proper concentration for a sufficient length of time. For example, wipes or gels with alcohol in them can be used to clean hands. The gels should be rubbed into hands until they are dry.

Studies have shown that influenza virus can survive on environmental surfaces and can infect a person for up to 2-8 hours after being deposited on the surface.