Message #45 From:
NewsBot Date: November 15, 2006 06:00:00 AM
CAMH News Results of Clinical Trial Demonstrate That a New, Non-invasive Test is Comparable to Invasive Tests in Identifying Patients Who Could Benefit from ICDs
CHICAGO--(BUSINESS WIRE)--New clinical trial results from the Alternans Before Cardioverter
Defibrillator (ABCD) trial were presented today at the American
Heart Association’s 2006 Scientific Sessions
conference in Chicago. The study found that a non-invasive test that
uses computer technology to predict a patient’s
risk for sudden cardiac death has proven itself comparable to an
invasive and more expensive procedure commonly used by cardiac
electrophysiologists to determine a patient’s
eligibility for an implanted defibrillator.
Primary Investigators Otto Costantini, M.D., and David S. Rosenbaum,
M.D., from the MetroHealth Medical Center campus of Case Western Reserve
University in Cleveland, Ohio, presented the results. The study,
sponsored by St. Jude Medical, Inc. (NYSE:STJ), compared the predictive
value of Cambridge Heart, Inc.’s (OTCBB:CAMH)
non-invasive Microvolt T-Wave Alternans (MTWA) Test™
with traditional, invasive electrophysiology (EP) tests in patients with
a history of ischemic heart disease at high risk for sudden cardiac
death (SCD).
This first-of-its-kind study investigated the use of MTWA, in which
electrocardiogram sensors are placed on the chest, to eliminate or
reduce the need for more costly and complicated invasive tests, where
catheter electrodes are placed into the patient’s
heart and electrical impulses are delivered to deliberately induce an
abnormal heart rhythm.
It is anticipated this new tool will be used by referring physicians to
better identify which patients have life-threatening arrhythmias and
need therapy provided by implantable cardioverter defibrillators (ICDs).
Current estimates show that only one in eight patients who needs such a
device actually gets one implanted. SCD from ventricular arrhythmias
accounts for nearly 50 percent of all cardiovascular deaths worldwide
and, although treatable with an ICD, it’s
difficult to predict which patients are most at risk.
Rosenbaum, the study’s senior author and
director of the MetroHealth Heart and Vascular Center, said, “The
current test used to identify patients at risk for SCD who might benefit
from ICD therapy has significant limitations. Consequently, most
patients who are likely to benefit from ICD therapy are not receiving
it, and conversely, most patients who receive ICDs never experience an
arrhythmia.”
“Many SCD events occur without warning and 95
percent of people do not survive the first episode. The ABCD trial will
give referring physicians a non-invasive means of categorizing a patient’s
risk,” said Eric S. Fain, M.D., executive
vice president of Development and Clinical/Regulatory Affairs for St.
Jude Medical’s Cardiac Rhythm Management
Division. “We are optimistic about the
possibility of providing an easier, more cost-effective, early warning
system for the more than 335,000 Americans stricken by SCD each year.”
“The positive and negative predictive values
of a MTWA-directed strategy and that of an EP test alone were
essentially identical,” said Costantini. “This
is most important, as the clinically relevant question today is not who
should receive an ICD, but who is unlikely to benefit from ICD therapy.
The use of a non-invasive approach to help us answer this question
represents a significant step forward.”
About EP and MTWA Testing
Typically, patients referred for one of the tests have already
demonstrated poor cardiac performance on an echocardiogram. The American
Heart Association estimates that 5 million Americans suffer from heart
failure, meaning their heart muscle is not pumping effectively. Many of
these patients may be candidates for an implanted defibrillator.
“The EPS is an invasive procedure in which a
catheter is threaded through a patient’s
veins into the heart where it delivers electrical stimulation to set off
an arrhythmia,” said Rosenbaum. “The
EP testing carries a small risk and requires a high degree of expertise,
limiting its ability to be used as a widespread screening tool.”
The non-invasive MTWA test is similar to a stress test, where the
patient walks on a treadmill while electrical sensors attached to the
skin surface record changes in the heart’s
electrical activity. However, unlike a stress test, the MTWA uses a
computer program to analyze subtle differences in the electrocardiogram’s
T-wave from one beat to the next. Physicians first noticed the
association between a difference in T-wave patterns and the risk of SCD
more than a century ago, but advanced technology has made it possible to
analyze them to predict SCD.
"The MTWA test provides a fast and inexpensive method for a physician to
identify high risk patients in need of ICD therapy right in their own
office," said Jeff Langan, president and CEO of Cambridge Heart. “The
results of this clinical trial show that the Spectral Analytic MTWA test
is comparable to the ‘gold standard’
invasive EPS, and therefore should provide physicians with additional
confidence in their diagnosis when utilizing our technology.”
Sudden Cardiac Death
SCD, also called sudden cardiac arrest, is unexpected death resulting
from an abrupt loss of heart function caused by a rapid irregular heart
rhythm (arrhythmia) or cardiac arrest. Many people have no symptoms
until the SCD occurs, and the majority of patients suffering SCD do not
survive the first episode. Cardiac arrest is reversible in most victims
if it's treated within a few minutes with an electric shock to the heart
to restore a normal heartbeat. According to the American Heart
Association, about 335,000 people a year die of coronary heart disease
without being hospitalized or admitted to an emergency room; most of
these are sudden deaths caused by cardiac arrest.
An ICD detects arrhythmias, both bradyarrhythmia (slow heart rates) and
tachyarrhythmia (fast heart rates), and delivers electrical
therapy-pacing pulses or defibrillation therapy as necessary to treat
these rhythm disorders and restore normal rate and rhythm to the heart.
When not needed, the ICD merely monitors the heart without delivering
any electrical energy. ICD therapy is often prescribed for patients who
have experienced at least one episode of ventricular tachyarrhythmia,
ventricular fibrillation, previous cardiac arrest or drug therapy that
was ineffective in controlling the tachyarrhythmia or that caused severe
side effects.
“Patients with heart damage, like those in
the study, are at increased risk of sudden death, a condition in which
the heart beats rapidly or chaotically and then stops,”
said presenter Costantini, who is assistant professor of medicine at the
MetroHealth campus of Case. “The condition
causes death within seconds unless the heart is given an electrical
shock, such as that delivered by an ICD, allowing a normal rhythm to
resume.”
About the ABCD Trial
The ABCD trial, initiated in May 2001, followed 566 patients, 18 years
of age and older, at 43 medical centers in the United States, Germany
and Israel, for a median of 1.9 years. Trial enrollment was completed in
2005 and follow-up ended in June 2006. All participants underwent MTWA
and EP tests with blinded and central adjudication of all test results;
St. Jude Medical ICDs were implanted if either test was positive and at
the physician’s discretion if both tests were
negative.
All patients had previous heart damage from coronary artery disease but,
importantly, none of the patients had previously experienced a cardiac
arrhythmia. The patients had both EP and MTWA testing and received an
ICD if either or both tests were positive, making this the first trial
in which patients received active therapy based only on a positive MTWA
test. “MTWA directed”
strategy was defined as positive if either the MTWA test was positive,
or if the MTWA test was indeterminate and the EPS was positive.
EPS and MTWA directed strategies had comparable one year positive (11
percent and 9 percent, respectively) and negative (96 percent and 95
percent, respectively) predictive values. Event rates were higher at one
year in patients with ICD therapy guided by both MTWA directed (HR=2.1,
p=.03) and EPS alone (HR=2.4, p=.007) strategies. The event rates for
patients with both a negative MTWA test and EPS were 2 percent.
Over two years, physicians monitored patients every six months to see if
their ICDs had been activated. Researchers found that the overall rate
of arrhythmic events was 7 percent after one year and 13 percent over
two years. The study showed that a strategy for screening patients for
SCD risk which includes MTWA could greatly improve the process of
selecting patients who can benefit from ICD therapy.
“There is rationale for incorporating more
than one risk stratification test, which is understandable, given that
changes produced by heart disease are very complex,”
said Rosenbaum. “It also makes sense because
the tests measure different things: EPS measures how electrical waves
spread across the heart as it beats and the MTWA measures how the heart
cells recover from those electrical activities. We need to adopt the
mindset for SCD screening that we currently have for breast cancer
screening: Like the mammogram, SCD screening should be applied to
appropriately selected patients at regular intervals. Ultimately the
patient and physician need to decide what level of risk is acceptable.”
Another important finding was the unexpected time dependency of risk
markers for SCD. “We found that the EP study
was not predictive until nine months or more and then remained
predictive for two years, while the MTWA test was predictive as early as
six months but was no longer predictive of outcomes by 12 months,”
Rosenbaum said. “The findings suggest that
the abnormalities in heart disease that increase the risk of arrhythmia
are highly dynamic and change over time, which suggests periodic
screening may be beneficial.”
About Microvolt T-wave Alternans
Cambridge Heart's Microvolt Alternans Test measures very small
beat-to-beat fluctuations of the T-wave amplitude on an
electrocardiogram (ECG). These tiny heartbeat variations –
measured at one millionth of a volt – are
detected using proprietary Alternans Sensors while the heart rate is
elevated by exercise, use of pharmacological agents or pacing. Extensive
clinical research has shown that patients who show symptoms of
life-threatening arrhythmias and test positive for Microvolt T-wave
Alternans are at significant risk for subsequent sudden cardiac events,
including SCD.
About MetroHealth
MetroHealth offers a full range of healthcare services at 14 sites
throughout Greater Cleveland. With its commitment to research, medical
education and community service, MetroHealth is able to provide the best
care to the most people. MetroHealth is a major affiliated teaching
hospital of Case Western Reserve University. In addition to the Heart &
Vascular Center (www.MetroHealthHeart.org),
services include a Level I trauma center, burn center, comprehensive
cancer care, high-risk obstetrics care, neonatal intensive care, women’s
health, pediatrics, medical and surgical specialties, family health,
internal medicine, mental health, rehabilitation, long-term care and
community health.
About Cambridge Heart, Inc.
Cambridge Heart is engaged in the development and commercialization of
products for the non-invasive diagnosis of cardiac disease, in
particular addressing such key problems in cardiac diagnosis as the
identification of those at risk of sudden cardiac arrest. The Company's
products incorporate its proprietary technology, Microvolt T-Wave
Alternans, coupled with its patented Spectral Analytic Method, which
have been cleared by the U.S. Food and Drug Administration to
non-invasively measure microvolt levels of T-wave alternans. The
Spectral Analytic Method MTWA test is the only MTWA reimbursed by
Medicare and major insurers in the United States, and is included in
guidelines for cardiac care in the United States and Europe. The
Company, founded in 1990, is based in Bedford, Mass., and is traded on
the OTCBB under the symbol CAMH. Cambridge Heart can be found on the
World Wide Web at www.cambridgeheart.com.
About St. Jude Medical
St. Jude Medical is dedicated to making life better for cardiac,
neurological and chronic pain patients worldwide through excellence in
medical device technology and services. The Company has five major focus
areas that include: cardiac rhythm management, atrial fibrillation,
cardiac surgery, cardiology and neuromodulation. Headquartered in St.
Paul, Minn., St. Jude Medical employs approximately 11,000 people
worldwide. For more information, please visit www.sjm.com.
Forward-Looking Statements
This news release contains forward-looking statements within the meaning
of the Private Securities Litigation Reform Act of 1995 that involve
risks and uncertainties. Such forward-looking statements include the
expectations, plans and prospects for the Company, including potential
clinical successes, regulatory approvals, anticipated future product
launches, revenues, margins, earnings, and market shares. The statements
made by the Company are based upon management’s
current expectations and are subject to certain risks and uncertainties
that could cause actual results to differ materially from those
described in the forward-looking statements. These risks and
uncertainties include market conditions and other factors beyond the
Company’s control and the risk factors and
other cautionary statements described in the Company’s
filings with the SEC, including those described in the Company’s
Annual Report on Form 10-K filed on March 16, 2006 (see Item 1A on pages
15-21) and in the Company’s Quarterly Reports
on Form 10-Q filed on August 7, 2006 (see Item 1A on page 32) and
November 7, 2006 (see pages 31-32). The Company does not intend to
update these statements and undertakes no duty to any person to provide
any such update under any circumstance.
