Exhibit 99.1

CardioDynamics Announces Five ICG Studies at Seventh Annual Heart
Failure Society of America Meeting; BioZ's Systolic Time Ratio
Parameter Predicts Mortality Outcome

    Seventh Annual Heart Failure Society of America Scientific Meeting

    SAN DIEGO--(BUSINESS WIRE)--Sept. 23, 2003--CardioDynamics
(Nasdaq: CDIC), the innovator and leader of Impedance Cardiography
(ICG) technology and manufacturer of BioZ(R) noninvasive cardiac
function monitoring systems, today announced the results of five ICG
clinical studies presented this week at the Seventh Annual Heart
Failure Society of America (HFSA) Scientific Meeting in Las Vegas.
    "There are over 75 BioZ ICG studies to date, but this is the first
time we have had five separate ICG studies presented at any medical
meeting," stated Michael K. Perry, CardioDynamics' chief executive
officer. "Each study and presentation helps further educate physicians
on the important role our ICG technology plays in cardiac medicine.
There is a growing demand to learn more about ICG's applications and
outcomes benefits, especially in the treatment of heart failure and
its major precursor, high blood pressure. Our BioZ heart monitors are
providing clinicians with objective patient data needed to predict
outcomes, test new therapies, validate or change older treatments and
better manage drug selection and dosing."
    In the first study, researchers at the Texas Heart Institute,
Houston, utilized the company's BioZ to assess the relationship
between systolic time ratio (STR), the ratio of electrical to
mechanical timing in the heart, and mortality in patients with heart
failure. A high STR value indicates poor heart function. The study of
49 active heart failure patients versus 24 deceased heart failure
patients showed STR was "high" in 51% of the active patients and 83%
of the deceased patients.
    The researchers concluded the results suggest that high STR
measurements correlate to mortality and NYHA (New York Heart
Association) class and that the BioZ parameters may be used in risk
stratification and management of outpatients with heart failure.
    The second study, by researchers at Christ Advocate Hospital,
Chicago, demonstrated the BioZ's stroke volume (SV) measurement as an
important parameter to identify diastolic heart failure and monitor
effectiveness of therapy. Without the BioZ, clinicians treating
diastolic heart failure rely on heart rate to determine whether the
patients have improved their ability to function. This study was
noteworthy as it demonstrated that stroke volume was more sensitive
than heart rate in assessing response to treatment in diastolic heart
failure patients.
    The third and fourth studies, conducted at Christ Advocate
Hospital, Chicago, and Owensboro Heart and Vascular, Owensboro, Ky.,
utilized the BioZ to track the blood flow effects of nesiritide, a new
heart failure drug that has been shown to reduce the length of stay
and 30-day re-admissions in hospitalized patients. The BioZ
demonstrated itself as an important tool in monitoring and measuring
the positive hemodynamic (blood flow) effects of nesiritide therapy.
    In the fifth study, researchers at Loyola University, Chicago,
tested and concluded that the BioZ TFC measurement may be a suitable
method for determining the severity of heart failure and/or the
presence of acute decompensation (patient instability).
    The company also announced that a special Continuing Medical
Education Symposium, Beyond the Four Quadrants: The Critical Emerging
Role of Impedance Cardiography in Heart Failure, is scheduled for
Wednesday, Sept. 24, at the Mandalay Bay Hotel, Las Vegas. The
University of Minnesota is sponsoring the symposium, and Philips
Medical Systems and CardioDynamics are providing an educational grant.
Marc A. Silver, MD, FACP, FACC, FCCP, FCGC, director, Heart Failure
Institute at Christ Hospital and Medical Center, Oak Lawn, Ill., will
chair the program, and Alan S. Maisel, MD, FACC, director, Coronary
Care Unit at San Diego Veterans Hospital, and John E. Strobeck, MD,
PhD, FACC, director, Heart-Lung Center, Hawthorne, N.J., will be
presenting. The symposium will educate attendees about ICG monitoring
methods and their clinical utility in the treatment of heart failure.

    About CardioDynamics:

    CardioDynamics (Nasdaq: CDIC), the ICG Company, is the innovator
and leader of breakthrough medical technology called Impedance
Cardiography (ICG). The company's BioZ(R) Systems are being used by
leading physicians around the world to help battle the number one
killer of men and women -- cardiovascular disease. Partners include GE
Medical Systems Information Technologies, Philips Medical Systems and
Vasomedical. The worldwide market potential for BioZ products is
estimated to be $5 billion and an additional $800 million in recurring
annual revenue for sensors. For additional information or to request
an investor package, refer to the company's Web site at www.cdic.com.

    Forward-Looking (Safe Harbor) Statement:

    Except for the historical and factual information contained
herein, this press release contains forward-looking statements, such
as market size, potential, growth and penetration rates, the accuracy
of which is necessarily subject to uncertainties and risks including
the company's sole dependence on the BioZ product line, and various
uncertainties characteristic of early growth companies, as well as
other risks detailed in the company's filings with the SEC, including
its 2002 Form 10-K. The company does not undertake to update the
disclosures contained in this press release.

    CONTACT: CardioDynamics
             Bonnie Ortega, Investor Relations
             888-522-2342, ext. 1005
             bortega@cardiodynamics.com
                 or
             Irene Paigah, Media Relations
             888-522-2342, ext. 1012
             ipaigah@cardiodynamics.com