Patient outcomes were improved by a 33% reduction in the proportion of patients that experienced worsening heart failure while using the Chronicle implantable hemodynamic monitoring device, designed to continuously track intracardiac pressure, body temperature, physical activity and heart rate in patients with systolic and diastolic heart failure.

The Chronicle, a small implantable device, is part of a comprehensive patient management system developed by Medtronic, Inc. The management system allows doctors to capture real-time data on the various physiological conditions of the heart, which is downloaded by the patient with a simple wave of a wand device over the chest area where the Chronicle is implanted. The wand contains a small computer device and is connected through the patient's phone line to transmit information to the physician over the Internet. The physicians caring for each patient then review the data, which are coded and encrypted to ensure Internet confidentiality.

Results of the COMPASS-HF (Chronicle Offers Management to Patients with Advanced Signs and Symptoms of Heart Failure) clinical trial were presented during the Late-breaking Clinical Trial session at the American College of Cardiology Annual Scientific Session. COMPASS-HF evaluated the use of the Chronicle implantable hemodynamic monitor (IHM), a new, investigational device.

Study results presented by Robert Bourge, MD, director of the Division of Cardiovascular Disease at UAB, include:

• The Chronicle IHM was used safely and reliably in the study population as measured by freedom from system-related complications and sensor lead failure.
• There was a 22% reduction in combined heart failure-related hospitalizations, emergency department (ED) and urgency care visits among patients whose physicians had regular access to data transmitted from the Chronicle monitor (did not reach statistical significance).
• There was a 41% reduction in combined heart failure-related hospitalizations, ED and urgency care visits among NYHA Class III patients whose physicians had regular access to data transmitted from the Chronicle monitor (statistically significant). Eighty-five percent of all patients enrolled in the study had NYHA Class III heart failure.
• Patient outcomes were improved as demonstrated by a 33% reduction in the proportion of patients that experienced worsening heart failure (statistically significant).

“These results demonstrate the benefits of remotely monitoring hemodynamics and congestion in many heart failure patients using an implantable monitor,” Bourge said. “Currently, physicians have no reliable, efficient way to measure this information, which presents a significant challenge in managing patients with heart failure and the detrimental cardiovascular effects of chronic fluid overload. We are now aware that with regular access to continuously measured, precise patient data from the Chronicle monitoring system, physicians can make real-time changes to medications, diet and fluid balance – often before patients even feel worsening heart failure symptoms – to reduce the need for hospitalization. This is an exciting technology that I expect will one day change the long-term management of heart failure for many patients.”

COMPASS-HF, supported by Medtronic, is the first randomized, controlled clinical trial to evaluate the utility of a continuous, ambulatory intracardiac pressure monitor to reduce heart failure hospitalizations and improve heart failure status. The Chronicle IHM, similar in size to a pacemaker, is implanted in the upper chest with a sensor located in the heart’s right ventricle. The monitor continuously tracks intra-cardiac pressure, body temperature, patient activity and heart rate. Patients transmit the information from home using a remote monitor via a standard phone line, and clinicians can then view the data on a secure web site. Clinicians then can note any changes in these readings – which may indicate changes in the patient’s clinical status – and, as appropriate, make treatment changes.

Twenty-eight U.S. clinical sites enrolled a total of 274 patients with NYHA Class III or IV heart failure and with at least one heart failure-related hospitalization or ED visit during the six months prior to baseline evaluation. All patients in the randomized, single-blinded, controlled study received optimal heart failure care (including standard drug and device therapy, daily weight measurements and regular access to experienced heart failure clinicians) and were implanted with the Chronicle IHM. Prior to Chronicle implantation, 40 percent of all patients also had another Medtronic pacemaker, implantable cardioverter-defibrillator or cardiac resynchronization therapy device.

Patients were randomized to receive optimal heart failure care alone (140 patients) or optimal heart failure care and therapy guided by the Chronicle IHM (134 patients). All patients were blinded to their randomization assignment and used the remote monitor to transmit data to their clinicians. Data from the Chronicle IHM was only reviewed and used by physicians for patients who were randomized to have therapy guided by Chronicle data. Patients were followed in the study for a minimum of 6 months.

“Every cardiologist knows the difficulty of keeping hard-to-manage heart failure patients out of the hospital,” said Steve Mahle, president of Medtronic Cardiac Rhythm Management. “Medtronic is dedicated to finding new ways to help improve the management of heart failure, and COMPASS-HF shows that with implantable hemodynamic monitoring clinicians can be alerted to early signs of heart failure deterioration and proactively tailor medical therapy to improve the patient’s condition. We are optimistic that the Chronicle device will soon move beyond investigational use for the benefit of many heart failure patients.”

More than 5 million Americans suffer from heart failure, and 550,000 new cases are diagnosed annually. The estimated direct and indirect cost of heart failure in 2004 was $25.8 billion, two thirds of which is due to hospitalization and home nursing care. Every year more than 1 million hospitalizations occur due to acute heart failure exacerbation, and it is estimated that approximately half of these are for a subset of 200,000 patients that are admitted at least twice per year. These patients are targets for more intense care and specialized follow up to prevent repeated admissions to the hospital.

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