A Medical Device Daily

Sometimes two therapies are better than one. Case in point: a study presented yesterday at Heart Rhythm 2009 showed patients fared better when treated with a combination of pulmonary vein isolation (PVI) and complex fractionated electrogram (CFE) guided therapy than with PVI alone or CFE alone for Atrial Fibrillation (AF).

St. Jude Medical (St. Paul, Minnesota) reported results from the Substrate versus Trigger Ablation for Reduction of Atrial Fibrillation (STAR-AF) trial. The findings were presented yesterday during a late-breaking clinical trials session at Heart Rhythm 2009, the annual Heart Rhythm Society's (Washington) scientific sessions in Boston.

The STAR-AF trial, sponsored by St. Jude, was an open, randomized, prospective, multicenter clinical trial involving 108 patients, administered in several Canadian and European centers. Designed as a three-arm trial, it compared the generally accepted treatment approach of PVI, with CFE guided therapy, and with a third arm that combined the two therapies. The primary endpoint of the trial was relief of AF episodes of 30 seconds duration or greater, up to 12 months after treatment.

Study results indicate that after one ablation procedure, a combination of PVI and CFE guided therapy demonstrated significantly higher freedom from AF, at 74%, as compared to PVI alone at 47% and CFE guided therapy alone at 29%. Importantly, 94% of patients who received the combination of these treatments remained off any anti-arrhythmic medications at the end of the 12-month follow-up period, St. Jude noted.

AF is a condition in which the upper chambers of the heart (atria) beat rapidly and erratically, affecting the heart's ability to adequately pump blood to its lower chambers (ventricles) and subsequently to the rest of the body. The STAR-AF trial studied patients with both symptomatic high burden paroxysmal (intermittent, but frequent and prolonged AF) and those with persistent AF. These two groups represent the largest subset of patients with AF; they experience varying degrees of intermittent AF episodes. The study participants had been unresponsive to medication that is meant to alleviate symptoms or the abnormal heart rhythm itself.

"While many unanswered questions remain about the origins of and best treatment options for AF, the results of STAR-AF indicate that perhaps traditional pathways are not the optimal ones. By mapping for the areas of CFE during AF ablation, we have demonstrated an incremental benefit for patients who historically may have undergone only a PVI," said Atul Verma, MD, an electrophysiologist in the Heart Rhythm Program at Southlake Regional Health Centre (Newmarket, Ontario, Canada), who was the principal investigator in the study. "Moreover, I feel that using an automated method for identifying the areas of CFE removes some of the subjectivity that exists in accurately targeting those regions of interest, and may be useful to physicians as they perform AF ablation."

CFEs are highly random and chaotic electrical signals in the atria that may be a source of origin or perpetuation of AF – they are extremely difficult to identify accurately by visual inspection alone. Therefore, an automatic algorithm from St. Jude Medical's EnSite system was used to identify these regions in the patients randomized to receive this treatment course. The CFE guided therapy alone and hybrid PVI and CFE guided therapy strategies were being studied because often a PVI alone will result in either recurrence of AF or another complicated atrial rhythm that requires additional patient intervention, St. Jude said.

"The results of the STAR-AF trial represent an important step toward understanding the best set of tools and therapies for treating cardiac arrhythmias, such as AF, and highlights St. Jude Medical's commitment to providing pioneering research to improve treatment of this condition," said Denis Gestin, president of the St. Jude Medical International Division. "Our sponsorship of this trial demonstrates our dedication to partnering with physicians to answer the many questions that exist about the treatment of AF."

AF is the most common abnormal heart rhythm and affects an estimated 2.3 million people in North America and 4.5 million Europeans. AF is responsible for 15% to 20% of all strokes, is a contributor to heart failure and is a leading cause of hospitalizations, according to St. Jude.

In other HRS news:

• Biotronik (Berlin, Germany) reported REPLACE registry during a late breaking clinical trials session.

According to the company, the REPLACE registry is a prospective, multi-center trial designed to provide physicians the data they need in advising patients and deciding on replacement of cardiac rhythm management devices.

The REPLACE registry collected data on patients who planned to have only their cardiac rhythm device, of any manufacturer, such as a pacemaker or implantable cardioverter defibrillator (ICD), replaced. Sponsored by Biotronik, the trial included 1,750 patients with devices from all cardiac rhythm management (CRM) industry manufacturers.

The trial was designed to define the complication and infection rates associated with all-cause device replacement. The trial also collected data on predefined major and minor complications, which could shape clinical practice guidelines for elective device replacements, the company noted.

"This prospective registry, due to the rigorous design, will become the gold standard for comparison," said Jeanne Poole, MD, director of electrophysiology at the University of Washington, and the national principal investigator of the REPLACE registry.

The REPLACE registry will provide the medical community exactly the information they have been looking for when considering the risks and benefits associated with performing device replacement procedures.

"Biotronik is committed to studies such as REPLACE that contribute valuable, patient-focused information to all parties concerned with improving patients' quality of life," said Jake Langer, president of Biotronik.

• Boston Scientific (Natick, Massachusetts) reported data from its ALTITUDE clinical science program that show real-word survival rates for implantable cardiac device patients exceeding rates from clinical trials. ALTITUDE analyzes outcomes data from patients monitored by the LATITUDE patient management system. Five-year survival rate data for patients using ICDs and cardiac resynchronization therapy defibrillators (CRT-Ds) were presented at HRS by Leslie Saxon, MD, chief of cardiovascular medicine at the Cardiovascular and Thoracic Institute, University of Southern California (Los Angeles) and chairperson of the ALTITUDE physician panel.

Boston Scientific has enrolled more than 130,000 patients on the LATITUDE system since its introduction in 2006, making it the most rapidly adopted remote cardiac device monitoring system in the industry, according to the company. The LATITUDE system enables physicians to schedule remote follow-ups of implantable cardiac device patients to monitor specific device information and heart health status. The system can also detect clinical events between scheduled visits and send relevant data directly to physicians. This regular, in-home monitoring offers convenience and peace of mind for patients.

Findings presented yesterday from ALTITUDE, which analyzed nearly 86,000 patients monitored by the LATITUDE system, include: Five-year survival rates for ICD patients of up to 92%; five-year survival rates for CRT-D patients of up to 78%.

"In contrast to clinical trials, the ALTITUDE program analyzes device therapy in real-world practice and offers insights into clinical event rates and disease progression for extensive ICD and CRT-D patient populations," Saxon said. "This observational cohort study represents the largest cardiac device patient cohort to date and clearly shows survival rates exceed those reported in randomized trials."

• NewCardio (Santa Clara, California), a cardiac diagnostic and services company, said it is introducing the NewCardio platform, QTinno and Visual3Dx at Heart Rhythm 2009. The company will be located at booth number 468 at the Boston Convention and Exhibition Center.

NewCardio said it believes that its QTinno, software-based, analytical technology is the industry's first solution for the reliable automated analysis of ECGs used to determine cardiac toxicity during drug development. Visual3Dx is designed to generate 3D information from the heart using standard 12-lead ECG data. It is expected to provide clinicians additional information on the extent and location of damage to the heart caused by a myocardial infarction to improve the speed and accuracy of diagnosis.