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GE, Siemens report on new cardiac imaging developments
[November 19, 2005]

GE, Siemens report on new cardiac imaging developments

(AHC Newsletters)AHA notebook

GE, Siemens report on new cardiac imaging developments

A Medical Device Daily Staff Report

DALLAS GE Healthcare (Waukesha, Wisconsin) said during this weeks American Heart Association (AHA; Dallas) annual scientific sessions that it has developed two new algorithms that, when used together, may help physicians predict whether a patient is at risk for sudden cardiac death (SCD).

The company added that for the first time, the algorithms could be used in combination with technology that is portable, making diagnostic tests available to patients anytime, anywhere. SCD accounts for about 930 deaths in the U.S. each day, according to the AHA.

The algorithms can be applied to the ECGs of patients who have had heart attacks to help determine their relative risk of sudden cardiac death, and help physicians determine if they are in need of an implantable cardiac defibrillator. In patients who have not had cardiac episodes, the algorithms can be used to help evaluate electrical instability in the heart.

Matthias Weber, vice president of GE Healthcares Diagnostic Cardiology business, said, One of the most compelling challenges facing physicians is the identification of which patients are at the highest risk for SCD. It is [our] hope that the wealth of detailed, accurate cardiac information provided by these algorithms will help physicians better understand which patients are at highest risk for SCD and enable them to prescribe proactive treatments that can help reduce these deaths.

When inputted with ambulatory electrocardiography (ECG) data, the new algorithms the Marquette T-Wave Alternans algorithm and the Marquette Heart Rate Turbu-lence algorithm have been shown to help predict if a person is at risk for SCD.

Ambulatory ECG data, also known as Holter monitoring, is commonly used by physicians to investigate whether such patient symptoms as fainting, dizziness or palpitations are caused by a heartbeat that is too slow, too fast, or very irregular.

Because GEs Holter system is portable, the company said it enables physicians to monitor a patients heart rate information during normal everyday activities. In conjunction with that Holter monitoring system, the T-Wave Alternans algorithm precisely detects fluctuations in the ECG waveform, identifying a pattern variation that can indicate SCD risk, GE said in a press statement.

It said the presence of T-wave alternans may help physicians predict which patients are at risk for SCD, enabling them to make earlier treatment decisions, such as whether a defibrillator should be implanted.

The Heart Rate Turbulence algorithm measures and compares the heart rate before and after premature beats, providing comparison data used to measure how the patients heart and autonomic nervous system work together, which can determine cardiac health.

Used together, these algorithms interpret complex cardiac rhythms that provide a more accurate, advanced way to determine which patients are at risk for SCD and would benefit most from an implantable defibrillator, said Dr. Richard Verrier, associate professor of medicine at Harvard Medical School and Beth Israel Deaconess Medical Center (both Boston).

He said this method for diagnosing patients should significantly benefit those patients who may be at higher risk for SCD or help in prescribing the most appropriate therapies to prevent SCD.

GE Healthcare also said data was reported from a clinical case study confirming that the LightSpeed VCT, GEs volume computed tomography (CT) scanner, is capable of capturing images of the human heart in as few as five beats.

The clinical case study data, collected by Dr. Jean-Louis Sablayrolles, head of CT cardiac imaging radiology at Centre Cardiologique de Nord (CCN; Saint-Denis, France), shows that the ability to scan the heart in five heart beats is a critical tool to help physicians improve the success rate of coronary CT imaging when compared with scan durations of 10 seconds or longer.

As a result, said Sablayrolles, physicians are able to get clear images of a broader patient population than typical scans done by non-volume CT systems.

This achievement in cardiac diagnosis is improving the standard of care for even those patients who previously were unable to undergo a non-invasive diagnosis because of poor breath-hold, he said. The extreme speed and enhanced image quality of the LightSpeed VCT are enabling doctors at CCN to scan patients in the shortest amount of time possible while obtaining remarkable cardiac images.

Stanley Katz, MD, chief of cardiology at North Shore University Hospital (Manhasset, New York), said: For the first time, physicians are able to non-invasively diagnose heart disease in at-risk patients, including patients who we were unable to scan previously due to either rapid heart beat or because they were unable to hold their breath long enough.

Additionally, a controlled clinical study is under way at Childrens Hospital and Health System (San Diego) to assess the clinical performance of the LightSpeed VCT for infants with heart defects. The study will compare the accuracy of the LightSpeed VCT with more-invasive cardiac catheterization techniques on children born with congenital defects of the heart and major vessels.

GE also said that it is partnering with more than 20 clinical collaborators to focus on large, in-depth research studies to further examine the benefits of cardiac CT. These academic institutions include the Medical College of Wisconsin; North Shore University Hospital; Cardiology Associates of Alabama; University of California Los Angeles - Harbor; Baylor University Hospital; and Cornell University Hospital.

Siemens Medical Solutions (Malvern, Pennsylvania) reported at AHA the Encompass III release on the companys Acuson Sequoia C512 ultrasound platform. The company said this latest in a series of three releases over the past 11 months continues to advance cardiovascular ultrasound, particularly for left ventricular (LV) imaging and congestive heart failure.

The Encompass III release offers physicians clinical application solutions and workflow features that enhance the features offered on both the Encompass I and II releases for the Sequoia platform. Encompass III includes an exciting new means to assess the hearts contraction mechanics using ultrasound information called Axius Velocity Vector Imaging (VVI), Siemens said in a statement.

The release also includes Axius Auto EF, a computer-aided detection technology that the company said automatically calculates ejection fraction without the need for operator interaction. Other features include a set of re-synchronization tools based on Doppler Tissue Imaging technology, and fourSight real-time 3-D imaging technology for transthoracic applications with a volumetric calculations package.

Using Axius VVI, clinicians can see a graphical presentation of tissue motion using arrows to display direction and relative velocity of motion in one ventricle, providing them the ability to see a freeze frame of motion at any point in the cardiac cycle. Siemens said this enables clinicians to easily visualize both contraction and relaxation mechanics and offers a new method for assessing cardiac function for the primary objectives of ventricular assessment and congestive heart failure.

VVI is a promising new technology that provides unique insight into ventricular mechanics, said Jim Thomas, MD, of the Cleveland Clinic Foundation. We have found it to be helpful in evaluating patients with hypertrophic cardiomyopathy and candidates for biventricular pacing.

The real-time 3-D transthoracic echocardiography (TTE) offerings called fourSight RT3D imaging builds on the Sequoia systems coherent image formation. RT3D provides accurate reconstruction of complex anatomy for improved calculation accuracy and reproducibility in volume measurements, the company said. The package also features the new 4Z1c RT3D transducer, which Siemens said is lighter and smaller than existing 3-D transducers.

SOURCE-Medical Device Daily

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