Editor’s Note: What should clinicians do when they need more diagnostic information than an initial exercise stress test can provide? A recent article in the journal Circulation looked at that question. (Selecting a Noninvasive Imaging Study After an Inconclusive Exercise Test. Blankstien, Ron, MD. DeVore, Adam, MD. Circulation. Vol 122. October 12, 2010.)

The American Heart Association recently updated their Appropriate Use Criteria statements. These are nuclear testing guidelines based on usage patterns that emphasize correct testing indications. As an adjunct they also published a nice clinical update summarizing noninvasive cardiac stress testing options. Use this information for:

Selecting the Right Cardiac Stress Test

1. Low risk, asymptomatic patients may not need further testing after an exercise stress or stress echo, unless test results are definitively positive for suspected coronary artery disease (CAD) or worsening CAD.
2. In low-to-intermediate risk patients Coronary CT scans can be used to rule-out severe coronary artery disease (CAD).
3. High-risk patients with known CAD will benefit greater from nuclear perfusion-based imaging.

Exercise Stress Testing

• It’s a good initial test for patients with known or suspected CAD.
• It’s a safe and inexpensive way to get valuable prognostic and diagnostic information.
• In addition to ST changes, testing gives info on important clinical markers such as functional aerobic capacity (FAC), symptomatic, hemodynamic and other ECG (arrhythmias or rate-dependant conduction defects) responses to physiological stress.

Exercise Stress Testing Limitations
Inconclusive tests are commonly due to:
• Insufficient workload or chronotropic incompetence (no heart rate increase)

• Inadequate BP response (<25mmHg increase)
• Baseline or resting ST depression > 1mm

• Baseline Left Ventricular Hypertrophy (LVH) (deep S-wave in V1 with a tall R-wave in V4, V5 or V6.

• Patients with physical limitations or certain arrhythmias like Wolf-Parkinson-White Syndrome (WPW) are not candidates.
• Diagnostic uncertainty still exists with both equivocal and positive test results.

To increase diagnostic accuracy additional testing modalities are often useful. Understanding the clinical strengths and limitations of the testing options is essential and keeping up with current clinical efficacy data can be challenging or confusing, even for cardiologists.

Stress Echocardiography

• Accuracy relies on visual confirmation of wall motion abnormalities (rest vs. stress).
• Increases specificity for CAD detection and valvular function without radiation exposure.
• For chronotropically incompetent patients or those unable to exercise a pharmacological (dobutamine) stress echo can be done.

Stress Echo Limitations
• Images are limited in patients with obesity or obstructive lung disease.
• Accuracy is reduced in patients with resting wall motion abnormalities (prior MI, paced rhythms, very poor EF% or certain cardiac surgeries).
• And although it’s accurate at detecting significant coronary disease, the test does not detect non-blood flow-limiting coronary blockages.

Single Photon Emission Computed Tomography (SPECT) Scan – Nuclear

• Robust prognostic value based on clinical risk correlation to severity of perfusion defect caused by CAD.
• Test results are valuable in determining the need for medical therapy vs. coronary intervention (angioplasty, balloon or stent placement).

SPECT Limitations
• “Attenuation” (scan irregularities due to fatty tissue) increase false-positives.
• Global ischemia (or “balanced” ischemia in all coronary arteries) can fool the camera and cause false-negatives.
• Cannot detect non-obstructive coronary blockages.

Positron Emission Tomography (PET) Scan — Nuclear

• Superior image resolution and better attenuation correction.
• Better diagnostic accuracy.
• Faster radiotracer results in lower radiation exposure.
• High reimbursement.

PET Limitations
• Significant portion of high reimbursement is consumed by very expensive PET camera and radiotracer costs.
• Current PET protocols cannot be performed with exercise stress, only pharmacological stress.

Cardiac Magnetic Resonance Imaging (MRI)

• Produces images of stress-induced wall motion abnormalities, cardiac structures, ventricular function and other forms of heart disease or inflammation (pericarditis, myocarditis) without radiation exposure.
• Pharmacological stressors (adenosine or dobutamine) are used to promote visual confirmation of ischemic areas.
• Similar diagnostic accuracy to SPECT, but without the annoying attenuation artifacts.

MRI Limitations
• Complex, limited availability and cannot be performed with exercise stress, only pharmacological stress.
• Can’t be done on patients with claustrophobia or patients with ICDs. Stents are ok.
• Occasional transient dark rim artifacts can show false-positives.

Coronary CT Angiography

• Produced high resolution images of coronary arteries.
• Has a high negative predictive value (those who don’t have CAD), but poor positive predictive value (those who have severe CAD).
• Better at identifying non-obstructive blockages. This helps direct medical therapy.

CT Limitations
• Requires normal kidney function and a low resting heart rate.
• Few studies done on the diagnostic accuracy.
• Has trouble detecting severe calcified blockages.
• Testing can be combined to utilize the diagnostic advantages of each modality.
• The combined diagnostic accuracy of these tests is currently the subject of many on going clinical studies.

Related Products

• Quinton Q-Stress
• The Quinton 9500 Series of cardiac stress systems
• The new Burdick 8500 12-Lead Resting ECG
• The new Burdick 8300 12-Lead Resting ECG
• CareCenter MD Diagnostic Workstation with ECG and Stress modules

One of our field service engineers, Ian Allison, wrote last week to let us know about a volunteer group in Bradford, England, that raised money to donate a complete Quinton Q-Stress cardiac stress testing system to the Bradford Royal Infirmary. Ian, who was involved in the installation, told us about the unveiling ceremony at the medical center.

Friends of the Bradford Royal Infirmary donated a Q-Stress cardiac testing system to the medical physics department.

The Friends of Bradford Royal Infirmary presented the £13,000 system to the medical physics department, which will use the cardiac monitoring equipment to test as many as 1,000 heart patients each year.

Mike Page, clinical technologist and section head of medical physics called the new system “an improvement on what we had previously and a real boost for the service,” according to an article in the Bradford Telegraph and Argus.

Consultant cardiologist Dr Sudantha Bulugahapitiya added the the Q-Stress system would improve the safety and quality of the service.

Volunteers with Friends of BRI raise around £100,000 each year to enable the hospital to purchase expensive equipment like the Q-Stress system.

Related Products

• Quinton Q-Stress cardiac stress machine
• Quinton TM55/TM65 stress treadmill
• Quinton Q-Tel cardiac rehabilitation management system
• Quinton CR60 rehabilitation medical treadmill

The Centers for Medicare & Medicaid Services (CMS) last week released a fee schedule for 2011 reimbursement rates that increases payments for cardiac rehabilitation.

While Medicare reimbursement rates for many procedures and services are slated to decrease in 2011, the rate for cardiac rehabilitation services (CPT codes 93798 and 93797) in a hospital-based or hospital off-campus program will rise 78% to $68.81. (The associated co-payment for patients will be $13.86.) This brings cardiac rehabilitation up to the level for pulmonary rehabilitation, which will be reimbursed at $62.98 under the new schedule. Office-based cardiac and pulmonary rehabilitation rates are different, and there will be regional differences in the new fee schedule.

The CMS fee schedule will go into effect Dec. 1, 2010, unless Congress acts to amend or delay it.

Hidden heart problems that elude traditional cardiac testing can now be spotted using the new T-wave test.

KABC Los Angeles recently profiled a woman whose doctor spotted a previously undiagnosed heart problem using the test. Freddie Holmes had no idea she was at risk for sudden cardiac arrest until her doctor, concerned that Holmes had experienced episodes of fainting, did a T-wave test. The test revealed an abnormal heart rhythm, and Holmes was given an implantable defibrillator that will restart her heartbeat if it stops.

Click to view the MTWA video

The T-wave test is similar to a stress test, but it uses specialized leads that can pick up electrical changes in the heart that are 1,000 times too small to be seen on an EKG.

“I look at myself, I have a very active lifestyle, I eat right, I exercise, I never would have dreamed in a million years that I would have a heart problem,” Holmes told KABC.

Microvolt T-Wave Alternans for Q-Stress testing, shown in this news video, is reimbursed by Medicare and by many, though not all, insurance companies. It combines the Cardiac Science Q-Stress system with Cambridge Heart’s unique MTWA testing system to detect “every-other-beat” patterns that are unique to patients at increased risk.

Related Products

• Quinton Q-Stress
• Quinton Eclipse Premier 12-Lead ECG Monitor
• Burdick Atria 6100 12-Lead Resting ECG
• Burdick Atria 3100 12-Lead Resting ECG
• CareCenter MD Diagnostic Workstation

University of Miami offensive line coach Jeff Stoutland was a busy man — so busy that when he experienced tightness in his chest and other symptoms of cardiac problems in May, he ignored them for as long as possible.

A treadmill stress test may have saved Jeff Stoutland's life. (photo: University of Miami)

But, as a story in the Palm Beach Post relates, it was just a matter of weeks before the symptoms were so painful that Stoutland was unable to do his regular workouts.

“I was getting crushed,” Stoutland told the paper. “I couldn’t go any longer.”

The 48-year-old coach made an appointment for a cardiac stress test. The results of the treadmill stress test were so dramatic that Stoutland was taken off the treadmill mid-test and admitted to the hospital. Just a few hours later, he underwent open-heart surgery to clear three blocked arteries.

Research at Columbia University Medical Center found that stress testing can be a life-saver for people like Stoutland who have chest pain but are not suffering a heart attack. Every year, more than 5 million people seek medical care for chest pain. Those who are having heart attacks can be diagnosed using electrocardiograms (EKGs), but for the rest, chest pain is often attributed to anxiety or physical activity.

The Columbia study, published in the June 15, 2003, issue of the American Journal of Cardiology, found that patients with chest pain who undergo a stress test have a significantly lower death rate that those who are not given a stress test. One of the reasons for the difference is that treadmill stress tests, which reveal blood flow deficiencies, can identify underlying coronary artery disease — blockage such as what Stoutland suffered.

The results of the study led to the creation of a chest-pain protocol, which includes recommendations for stress tests, at Columbia University Medical Center, NewYork Weill Cornell Medical Center and the Allen Pavilion at NewYork-Presbyterian Hospital.

Stoutland is now back at work coaching the Hurricanes. He advises others to do what he didn’t: Take care of their health, and visit the doctor if they have chest pains.

Related Products

• Quinton Q-Stress cardiac stress machine
• Quinton TM55/TM65 stress treadmill
• Quinton Q-Tel cardiac rehabilitation management system
• Quinton CR60 rehabilitation medical treadmill

The American Heart Association recommends that cardiac stress testing preceded exercise programs for certain sedentary patients.

One of the toughest tasks for primary care physicians is getting sedentary middle-aged patients off the path to cardiovascular disease and onto the path for health. A Clinician Update in the June 15, 2010, issue of Circulation has advice for doctors on when and how to prescribe exercise, including when to start the process with a treadmill stress test.

The article recommends that physician conduct a preparticipation screening to rule out any conditions, such as existing heart problems, that would make exercise risky. The authors note that some authorities recommend that certain sedentary patients get a cardiac stress test before embarking on an exercise program:

The American College of Cardiology and American Heart Association recommend exercise treadmill testing for asymptomatic patients with diabetes mellitus, men older than 45 years of age, and women older than 55 years of age before they undertake vigorous exercise, with the decision to incorporate myocardial imaging based on the baseline ECG and the pretest probability of coronary artery disease.

Unless the preparticipation screening reveals cardiac problems, physicians are urged recommend a moderate form of exercise, such as walking 5 times a week, to start, with resistance training to be add after the patients is exercising for 30 minutes in each session.

Related Products

• Quinton Q-Stress cardiac stress machine
• Quinton TM55/TM65 stress treadmill
• Quinton Q-Tel cardiac rehabilitation management system
• Quinton CR60 rehabilitation medical treadmill

Neil Barnes is the biomed/clinical engineering supervisor at The Heart Hospital at Paris Regional Medical Center in Paris, Texas. He’s committed to tracking, registering, and generally taking care of medical devices, so that’s why he did the paperwork to register their new Cardiac Science Burdick Vision 5L Holter recorders.

“We try to register everything because that way we get alerts and updates,” Barnes said. “I saw it come in, so I took care of registering it.”

By registering, Barnes helps Paris Regional stay up to date with any communication regarding the Burdick Holters.

Barnes has worked at Paris Regional since 1982. He shares the local pride in the hospital and the city — which boasts “the world’s second-largest Eiffel Tower, with a cowboy hat,” he says.

Currently, half of his time is spending working with cardiac diagnostic devices at the Heart Hospital, where he supports equipment that includes a Cardiac Science Q-Stress system that is part of nuclear medicine testing. The new Holter recorders will be used with the hospital’s Vision Premier Holter System.

Neil, a big thanks for registering.

Related Products

• Quinton Eclipse Premier 12-Lead ECG Monitor
• Burdick Atria 6100 12-Lead Resting ECG
• Burdick Atria 3100 12-Lead Resting ECG
• Burdick Universal ECG

The Centers for Medicare and Medicaid Services have launched a new website that will provide the most up-to-date information about its Medicare and Medicate EHR Incentive programs.

These programs provide incentive payments to physician practices and hospitals as they adopt, implement, upgrade, and demonstrate meaningful use of certified EHR and EMR technology.

The website is a valuable resource for professionals exploring data management and networking for their organizations. The FAQ provides the latest and most detailed answers to questions such as:

• Who is responsible for demonstrating meaningful use of certified electronic health record (EHR) technology, the provider or the vendor?
• What if my electronic health record (EHR) system costs much more than the incentive the government will pay? May I request additional funds?
• If I already have an EHR that has been certified by the CCHIT, will I have to buy a new system if the government mandates that only EHRs that meet a higher certification level are considered certified EHRs?

The website also provides information tailored to assist individual practitioners, hospitals, and state EHR incentive programs.

Cardiac Science is committed to helping our customers achieve meaningful use of EHR and EMR systems by working closely with leading vendors whose products interface with HeartCentrix, our connectivity and cardiac data management solution. Our EMR partners include Allscripts, eClinicalWorks, Epic, GEMMS, gMed, Greenway, MEDENT, MicroMD, NextGen, and Sage Intergy.

Ten years ago, Florida TV newsman Judd Cribbs took a treadmill stress test.

He was just 38 at the time, and had no obvious health problems. But it was Health Heart Week in his community, and he was curious to see how he’d do.

Q-Stress stress machine for exercise stress testing

The results were not what he’d expected.

“After an extremely short time, I almost vomited and fainted, in that order,” Cribbs recalls in an article published last week in the Los Angeles Times. The physician monitoring the treadmill stress test told Cribbs he’d been given a wake-up call.

Cribbs listened. He took up running and now runs 5Ks and marathons. He reports that he’s lost 25 pounds. All because of one cardiac stress test.

What’s a cardiac stress test?

The exercise stress test (also called an exercise electrocardiogram) is often the first type of stress test used to check for suspected heart problems. You walk on a treadmill or ride on a stationary bike while your heart rate, blood pressure, and heart rhythm are monitored. To monitor heart rhythm, electrodes placed on your chest are connected to an electrocardiograph (ECG) that creates a visual record of your heart’s performance. Medical personnel monitor all aspects of the stress testing.

In many hospitals, software such as Cardiac Science’s Quinton Q-Stress is used to store cardiac stress test results as part of your electronic medical records.