How to Buy a Cardiac Stress Testing System

Cardiac stress testing systems use exercise and monitoring devices to provide information on how your heart functions during physical stress.[1] Most heart conditions become obvious and are easier to diagnose when the heart is working hard. The equipment needed includes a treadmill or stationary bike, an electrocardiogram (ECG), a blood pressure cuff and various electrodes attached to a computerized monitoring system. Only qualified medical professionals should operate cardiac stress testing systems and interpret the results. For people who can't exercise, drugs can be given to increase heart rate, which is referred to as a pharmacological stress test.

Part 1 - Assembling a Cardiac Stress Testing System

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→ Pick between a treadmill or stationary bike. The main component of an exercise-based cardiac stress system is some sort of exercise machine. The two main options are a treadmill or a stationary bike. Both are commonly used in hospitals and clinics, but there are pros and cons to each type of machine. For example, gripping the railing of the treadmill too tightly or leaning against it for support can skew the results of a cardiac stress test.

→ As the cardiac test progresses, the speed and incline of the treadmill increases, whereas the pedal resistance increases on a stationary bike. Both are automatically controlled.

→ Treadmills are easy to get on and off when not in motion, but trying to stop, get off or accidentally tripping while the treadmill is in motion can cause injury.

→ Stationary bikes are a little more difficult to mount and get off of, but more stable and less likely to cause an injury due to some accident. Bikes are also typically half the cost (or less) compared to treadmills.

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→ Decide on an electrocardiogram (ECG). An ECG is a diagnostic tool used to assess the electrical and muscular functions of the heart. The heart's electrical activity (contractions, rate and rhythms) are measured by electrodes placed on the skin — typically 6 placed across the chest over the heart and 1 on each arm and leg for a total of 10 electrodes. The signals received from each electrode are recorded and shown on a computer monitor, and printed recordings of the information is actually the electrocardiogram.

→ ECG units are the most expensive part of a cardiac stress testing system, costing between three to five times more than the exercise equipment, on average.

→ While it's a relatively simple test to perform, ECG interpretation requires specialized medical training and experience. Don't attempt to use one at home if you're untrained.

→ Decide on the size of the print outs. ECG machines that print out 8.5 x 11 inch sheets of paper are often preferable because they are easier to handle and store — although paper costs will be higher.

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→ Choose a blood pressure cuff. A blood pressure cuff (also called a sphygmomanometer) is also needed during a cardiac stress test in order to monitor blood pressure. Normal blood pressure should be under 120/80 (systolic/diastolic) while resting, although that can slightly increase with exercise and during the stress test. The cuff is attached to an arm during the test to make sure blood pressure doesn't get too high or too low while exercising.

→ Blood pressure that's too high is called hypertension, whereas hypotension is the term for blood pressure that's too low. Hypertension is usually an indicator of cardiovascular disease.

→ Sphygmomanometers used for cardiac testing are fully automated and inflate/deflate by themselves. The readings are recorded on a computer monitor along with the other heart measurements.

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→ Consider breathing equipment also. Some cardiac stress test systems also monitor breathing rates. With these systems, a tube is attached to the mouth while the nose is plugged, and a machine records how well you breathe during the exercise. Normal resting breathing rate is between 12 – 20 breaths per minute and that's expected to rise moderately during the testing. The equipment can monitor hyperventilation, which is a reason to stop the testing.

→ Breathing equipment shouldn't be used on people with asthma during cardiac stress testing.

→ Breathing equipment and all the other accessories can be purchased at medical supply stores or ordered online from medical equipment distributors; however, you may need to prove your medical credentials before purchasing.

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→ Don't forget the electrodes. Electrodes are the least expensive part of the system, but vital because they transmit electrical information of the patient's heart to the ECG and computer system. Electrodes are small, flat, sticky patches that attach to wires — they can be disposable (one-time use) or reusable. Keep in mind that 10 electrodes are used per test, so buy them in bulk or be prepared to clean/sanitize the reusable kind often.

→ Along with the reusable electrodes, you'll need to buy some conducting gel, alcohol swabs to clean the skin, and medical tape to attach the electrodes to the skin.

→ Electrodes come in different diameters, but for cardiac testing, get ones that are at least 1.5 inches (3.8 cm) in diameter if not a little bigger.

Part 2 - Buying a Cardiac Stress Testing System

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→ Decide between new or used equipment. A new cardiac stress testing system can easily cost upwards of $10,000 or more, although good used systems can be half that and maybe still have some warranty left. The benefits of buying new medical equipment is that it's often easier to finance and/or lease, it has more warranty and you can customize the set-up to your specific needs. Tax write-offs may also be easier. Used equipment is obviously more affordable, but maybe more difficult to finance. The systems are tested and refurbished to work perfectly, but the warranty is almost always less than new equipment.

→ Do an internet search for reviews and quality ratings of specific manufacturers. Compare equipment from different countries — German made is often in higher quality (and more expensive) than Chinese made, for example.

→ Both treadmills and stationary bikes are easy to get used, either online or from local doctors and therapists in your area. Most are only very lightly used.

→ If you have to cut corners to come in on budget, do so with the treadmill / bike and blood pressure cuff, but try to get the best ECG machine you can.

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→ Decide if you want to use a medical equipment representative. There are medical equipment reps that deal with both new and used equipment. If you choose to deal with a medical rep when purchasing a cardiac stress testing system, you'll likely pay a little more to account for their commission, but you might get some good advice and be able to avoid some pitfalls. You may also have established a good relationship with a medical rep from buying other equipment, so there's an element of trust to consider. On the other hand, thanks to the internet, you can browse a wide range of equipment from around the world online without a medical rep. You'll like get a better price and not feel pressured into buying certain brands or packages.

→ If you buy from a medical rep you'll likely get a demonstration of your cardiac stress testing system in your office.

→ Medical reps are usually easier to get a hold of to troubleshoot problems compared to customer service departments with internet companies.

→ Although internet shopping is all about saving money, be mindful of potentially expensive shipping rates and insurance costs.

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→ Configure everything together on a computer station. Once you've got all your equipment, you'll need to configure and integrate it into a computer system with a monitor. Most cardiac stress testing systems include the computer and necessary software so you can clearly see how the patient is doing. Make sure to buy a system that shows all 10 leads on the same screen (in real-time) in order to avoid having to constantly switch between screens — it can be annoying and distracting. However, remember that your eyes shouldn't always be on the screen; you also need to watch the patient for any obvious changes that suggest the test should be stopped.

→ You'll also need to buy a mobile cart to house the above-mentioned equipment and computer system — these run between $300-500 for sturdy ones. Get one with wheels so you have the freedom of moving it around the testing room.

→ To store on your cart, you also need to buy alcohol wipes, tissues, medical tape, conductance gel, latex medical gloves and hand sanitizer.

Part 3 - Understanding Cardiac Stress Testing

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→ Know what it's used for. Doctors usually recommend cardiac stress testing to help diagnose coronary heart disease (CHD) and/or understand its severity. CHD involves plaque build up (atherosclerosis) in the coronary arteries that supply blood and oxygen to the heart muscle. It leads to potential chest pain (angina), hypertension and heart attack. Signs of CHD aren't always obvious while at rest, but they become apparent with cardiac stress testing.

→ Another reason to get a cardiac stress test is to diagnose heart rhythm problems called arrhythmias. Arrhythmias develop when the electrical impulses coordinating the heart rhythm don't function properly — the heart then beats either too fast, too slow or irregularly.

→ Stress testing also helps to guide treatment for heart problems — to see how well treatment is working or to establish a different treatment plan. It can also help determine the timing of cardiac surgery (valve replacement).

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→ Learn how to do it. There is a lot to learn to be able to run a cardiac stress test on a patient and then to interpret the results for them. It takes significant medical training and hands-on practical experience to gain the knowledge, ability and confidence. In general, the American Hear Association states that non-doctors with the appropriate training and sufficient experience can conduct and oversee cardiac stress tests without a doctor present, but a doctor must be present when a high-risk patient is being tested.

→ Non-doctors typically include clinical exercise physiologists, registered nurses, nurse practitioners, physician assistants and physiotherapists.

→ Doctors and non-doctors who supervise stress tests should perform at least 200 tests to establish proficiency and about 50 tests yearly to maintain proficiency.

→ Non-doctors must be capable of screening for and identifying high-risk test patients and then alert the supervising doctor.

TIPS

→ Although the entire appointment can take an hour or more, the actual exercise time for a cardiac stress test is usually between 7-12 minutes.

→ It's a good idea to wear comfortable clothes and shoes suitable for walking during cardiac stress testing.

→ Smoking interferes with the results of stress testing due to the effects of nicotine.

→ Don't take diabetes medication or skip a meal before stress testing if you have diabetes.