Cardiac Pathways Reports First Human Use of Arrhythmia Mapping System for Ischemic Ventricular Tachycardia; Improved Diagnostic Procedure a Critical Step Towards a Cure for Rhythm Disturbances That Result After Heart Attack.

SUNNYVALE, Calif.--(BUSINESS WIRE)--Dec. 7, 1995--Cardiac Pathways Corporation announced today the first human use of its Arrhythmia Mapping System at the University of Leiden in The Netherlands on Nov. 29, 1995.

The Arrhythmia Mapping System is part of an integrated cardiac ablation system being developed by Cardiac Pathways to rapidly and effectively diagnose and treat patients with complex tachyarrhythmias, or abnormally rapid heart rhythms. The procedure was performed on a 62-year-old patient suffering from ventricular tachycardia, a potentially lethal rapid heart rhythm that can result after a heart attack. Over 400,000 people each year suffer from some type of ventricular tachycardia.

Need for Faster Mapping

Today common therapies for treating ventricular tachycardia include drugs and the automatic implantable defibrillator, an electronic device that delivers an electrical shock to the heart to terminate the dangerous rhythm. Neither of these therapies is curative. Minimally invasive catheter ablation has been used in recent years to treat a variety of simple tachycardias by using radiofrequency energy to selectively destroy the small amount of heart tissue responsible for the rhythm disturbance.

Unfortunately, catheter ablation to date has had limited success in treating many of the tachycardias that result after a heart attack, largely due to the time-consuming nature of current diagnostic methods. In order to locate the exact area requiring ablation therapy, the physician must probe the inside surface of the heart with a single catheter electrode while the patient is experiencing the tachycardia. Many of the ventricular tachycardias that result after a heart attack are so rapid that the patient cannot tolerate this lengthy diagnostic or "mapping" component of the ablation procedure.

In response to the limitations of single-point catheters, Cardiac Pathways has developed a mapping "basket" catheter containing 64 electrodes. The catheter is introduced in a collapsed state, like a folded umbrella, to enable its traverse through the arteries to the heart. Once in position in the left ventricle, the main pumping chamber of the heart, the catheter is fully deployed, taking on an oval shape. The catheter has eight arms each containing eight electrodes, enabling mapping of the entire left ventricle within several heartbeats, a critical step towards enabling ablation as a first-line therapy for ventricular tachycardias that result from ischemic coronary artery disease.

Using a sophisticated, internally developed Arrhythmia Mapping System based on a Sun SparcStation 20, the Cardiac Pathways system is designed to allow the physician to identify the exact area in the heart that is responsible for the ventricular tachycardia in seconds instead of hours. In its first human use, the Cardiac Pathway's system successfully identified three different sites responsible for ventricular tachycardias within 73 seconds, compared to three to four hours required by single-point mapping catheters.

In September 1995, the Company filed an Investigational Device Exemption (IDE) with the Food and Drug Administration (FDA) for the Arrhythmia Mapping System and is awaiting approval to begin a clinical investigation in the U.S.

Cooled Ablation System in Clinical Trials

The Cardiac Pathways Arrhythmia Mapping System is used in conjunction with the Company's Cooled Ablation System -- the first radiofrequency cardiac ablation system to enter U.S. clinical trials for ventricular tachycardia due to coronary artery disease. Nine clinical sites in the U.S. and four sites in Europe have joined the Cooled Ablation System clinical study since the Company received an IDE from the FDA in June 1995.

The Cooled Ablation System includes a radiofrequency generator and features a catheter with a proprietary cooling system to prevent overheating at the tip of the catheter, an occurrence that can limit the effectiveness of ablation. This advance is thought to be particularly important in treating ventricular tachycardia due to coronary artery disease. The Cooled Ablation System, together with the Arrhythmia Mapping System, represents a complete system solution for the diagnosis and treatment of ischemic ventricular tachycardia. Marketing Clearance Granted for Diagnostic Catheter System

Cardiac Pathways also announced that clearance has been received from the FDA to begin commercialization of its Trio and Ensemble diagnostic catheter system. This system consists of the world's smallest catheters used in electrophysiology studies to diagnose tachycardias. The Trio and Ensemble system will be marketed and distributed by Arrow International of Reading, Penn., in the U.S. and in certain international territories. In March 1995, Arrow acquired the exclusive distribution rights to the Trio and Ensemble system and certain other Cardiac Pathways products in international markets in exchange for an equity investment and license fee.

William N. Starling, the President and Chief Executive Officer of Cardiac Pathways said, "These recent significant accomplishments position our Company to become a leader in cost-effective treatments for ventricular tachyarrhythmias. In addition, many of the technology platforms currently being developed for ventricular tachycardia are also being applied to the development of effective treatments for atrial fibrillation -- another prevalent and serious type of arrhythmia that currently lacks an effective treatment."

Founded in 1991, privately held Cardiac Pathways is developing minimally invasive, clinically superior systems to diagnose and treat cardiac tachyarrhythmias. The Company's products are innovative systems for diagnostic mapping, or pinpointing the source of the tachyarrhythmia within the heart, and for performing ablation treatment, a nonsurgical technique for neutralizing heart muscle cells responsible for starting or maintaining dangerously rapid heart rhythms. Cardiac Pathways combines expertise in mapping and ablation hardware with advanced catheter development capabilities to offer clinicians a complete diagnostic and therapeutic systems solution. Cardiac Pathways has their headquarters in Sunnyvale, Calif. -0-

Note to Editors: Press kit available upon request.

CONTACT: Cardiac Pathways Corporation

David W. Gryska, 408/737-0505