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University of Iowa News Release

May 31, 2006

UI Researchers Help Show Heart Technology Benefits

A University of Iowa Heart and Vascular Care physician who helped lead a large international research trial said the results show that patients might benefit from using advanced technology to help regulate the beating of their hearts.

Brian Olshansky, M.D., UI professor of internal medicine and director of cardiac electrophysiology at UI Hospitals and Clinics, served as the co-principal investigator of the study. Called Inhibition of Unnecessary Right Ventricular Pacing with AV Search Hysteresis in ICDs (INTRINSIC RV), the multi-center, randomized trial enrolled more than 1,500 patients at 108 centers in the United States, Germany, Italy and Australia.

The research was designed to advance the understanding of a proprietary feature that minimizes unnecessary right ventricular pacing in patients who received the Boston Scientific Company's market-released dual-chamber implantable cardioverter defibrillators (ICDs). A dual-chamber ICD can pace or sense in both the upper and lower chambers of the heart.

The results showed benefits of dual-chamber pacing in a majority of patients. While the trial was not designed to test for superiority, investigators noted that patients randomized to dual-chamber pacing tended to have a lower risk of combined all-cause mortality and heart failure hospitalizations compared to those randomized to the single chamber pacing arm.

"This trial highlights the importance of evidence-based medicine to further the understanding of advanced-feature medical devices, because INTRINSIC RV actually refutes the notion that dual-chamber ICD programming poses an inherent safety risk," Olshansky said. "In fact, by using AV Search Hysteresis, outcomes with dual-chamber programming performed as well as, if not better, than single-chamber programming."

University of Iowa Health Care describes the partnership between the UI Roy J. and Lucille A. Carver College of Medicine and UI Hospitals and Clinics and the patient care, medical education and research programs and services they provide. Visit UI Health Care online at

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