November 18, 2003

FOR: ZOLL Medical Corporation

Chief Financial Officer
ZOLL Medical Corporation
(978) 421-9655
PRESS CONTACT: Robert Minicucci
Corporate Communications Manager
ZOLL Medical Corporation
+1 (978) 421-9832


New Clinical Studies Discuss Results of the ZOLL Rectilinear Biphasic Defibrillation Waveform

Tuesday, November 18, 2003 – ZOLL Medical Corporation (NASDAQ: ZOLL) today commented on several new clinical studies. One study abstract—released today—discussed the performance of the ZOLL Rectilinear Biphasic (RLB) waveform in the pre-hospital setting (ORBIT Trial). The presentation was made at a plenary session of more than 7,000 attendees at the American Heart Association’s Scientific Sessions in Orlando last week. In addition, ZOLL also commented on two other animal studies, which discussed the advantages of the RLB waveform in the defibrillation of pediatric patients.

ORBIT Trial Abstract
The study abstract, presented by Laurie J. Morrison M.D. of Sunnybrook Hospital and Women’s College Health Sciences Center, Toronto, reported preliminary results of a comparison of the ZOLL RLB waveform with a conventional monophasic waveform. ORBIT (Out of Hospital Rectilinear Biphasic Investigation and Trial) enrolled 4,532 cardiac arrest patients treated by the Metropolitan Toronto EMS Service. The presentation was given at the Late Breaking Clinical Trials Plenary Session. It included the analysis to date of 436 out of 540 patients with ventricular arrthymias requiring defibrillation.

Dr. Morrison, the principal investigator and Associate Professor, Division of Emergency Medicine, University of Toronto, said, “ORBIT is the world’s largest and most comprehensive study ever undertaken in an out-of-hospital setting to look at the advantages of biphasic waveforms for defibrillation. While our interim results, as reported at the plenary session, showed an improvement in shock success from 45% to 54% over the monophasic waveform at a p value of 0.06, we have more than 100 additional patients to enter into the final analysis before submission for publication.”

Richard A. Packer, President and Chief Executive Officer of ZOLL, said, “The data reported today demonstrated that shocks from the ZOLL RLB waveform are as good as—or better than—monophasic waveform shocks in terminating lethal ventricular arrhythmias. While there was a trend in favor of superiority, results from additional patients must be analyzed to have sufficient data to demonstrate the study hypothesis of RLB waveform superiority.”

Mr. Packer added, “ORBIT is the largest trial ever reported for any biphasic waveform and the first to document the performance of a biphasic waveform in a typical EMS system operating at the advanced cardiac life support level, as opposed to AED use by first responders. It also compared the ZOLL RLB waveform to a typical damped sine monophasic waveform in its control group in contrast to an earlier low energy biphasic trial that used a truncated exponential monophasic waveform as the control. The researchers have more data to analyze, such as time to shock, definition of success, and admission to hospital before we can make any firm conclusions. At this point, we think it is an exceptionally well designed study, which could become a landmark.”

Animal Studies Discuss RLB Waveform for Pediatric Patients
Mark Niebauer M.D., an Associate Professor of Internal Medicine and the Director of Electrophysiology at the University of Nebraska Medical Center, Omaha reported on two studies in animals related to the advantages of the RLB in defibrillation of pediatric patients. Data relating to the “Superiority of the Rectilinear Biphasic Waveform to the Damped Sine Waveform for Ventricular Fibrillation in Pediatric Size Piglets” was presented in a poster session held in conjunction with a Resuscitation Science Symposium. The study showed that “the RLB successfully defibrillates the pediatric size piglet at significantly lower energies than the MDS (Monophasic Damped Sine). Moreover, it achieved this success rate at significantly higher impedance.”

In a second study, Dr. Niebauer reported on the “Adverse Hemodynamic Effects of Higher Energy Defibrillator Shocks in Pediatric Size Piglets: Protective effect of the Rectilinear Waveform.” He reported that higher energies produce a significantly higher degree and duration of hypotension, and that RLB shocks are overall safer than MDS shocks even at the same 200J level.

Commenting on these findings, Mr. Packer said, “Dr. Niebauer’s studies again show the advantages of using lower energies and the superiority of the ZOLL Waveform over the older, higher energy monophasic waveforms, confirming earlier work done in adults. We are pleased to see the results from these clinical trials become public and look forward to reporting on ongoing research in the future.”

ZOLL Medical Corporation (NASDAQ: ZOLL), with worldwide headquarters in Chelmsford, Massachusetts, designs, manufactures, and markets resuscitation solutions. Pacing and defibrillation devices, including ZOLL’s M Series and AED Plus, and LIFECOR, Inc.’s LifeVest™ Wearable Defibrillator; and circulatory assist devices such as Advanced Circulatory Systems, Inc.’s ResQPOD™ Circulatory Enhancer and Revivant Corporation’s AutoPulse™; are used by health care professionals, emergency medical service providers, and first responders to diagnose and treat cardiac arrest wherever it may occur. ZOLL also designs and markets software that automates the collection and management of both clinical and non-clinical data. ZOLL has operations in the United States, Canada, the United Kingdom, Germany, France, the Netherlands, and Australia, and business partners in all of the world’s major markets. For more information about ZOLL, its products and partners, visit or call 978-421-9655.

Certain statements contained in this press release, including statements regarding the anticipated development of the Company’s business, the anticipated growth in the hospital market, our ability to grow AED sales and increase AED market share, our outlook for the Company, our anticipated sales and earnings growth, our beliefs regarding the North American market, our ability to successfully build our AED business and our ability to grow our International sales, and other statements contained herein regarding matters that are not historical facts, are “forward-looking” statements (as defined in the Private Securities Litigation Reform Act of 1995). Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Factors that could cause actual results to differ materially from those expressed or implied by such forward-looking statements include, but are not limited to, those factors discussed in the section entitled “Risk Factors” in the Company’s Quarterly Report on Form 10-Q filed with the SEC on August 13, 2003, including the future performance of the direct sales operations, as well as uncertainties regarding the market acceptance and profitability of the ZOLL AED Plus, the length and severity of the current economic slowdown and its impact on capital spending budgets, the reduction in overall capital equipment expenditures in the hospital and pre-hospital markets, the impact of governmental budget restraints on the purchase of capital equipment, the continued war in the Middle East, the impact of the war on terrorism, the potential disruption in the transportation industry on the Company’s supply chain and product distribution channels, and the desire or ability of other parties to purchase the Company’s products.

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