First Patient Enrollment In Clinical Study On Long-Term Cardiac Monitoring For Detection Of Atrial Fibrillation After Cryptogenic Stroke

Main Category: Cardiovascular / Cardiology
Also Included In: Stroke;  Medical Devices / Diagnostics;  Clinical Trials / Drug Trials
Article Date: 15 Apr 2009 - 5:00 PDT

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Transoma Medical, Inc., manufacturer of Sleuth AT™, the only wireless, automated implantable cardiac monitoring system with programmable and frequent electrocardiogram (ECG) sampling, announced the first enrollment and implant in a long-term study to monitor patients who have suffered a cryptogenic stroke (of unknown origin) to determine if atrial fibrillation (AF) is present. The implant was performed on April 10 by Dr. Emile Daoud, electrophysiologist, at Ohio State University Medical Center in Columbus. The company received FDA 510(k) marketing clearance for Sleuth AT, its next-generation product, on Feb. 11, 2009.

"It is believed that as many as 20 percent of cryptogenic strokes are caused by asymptomatic atrial fibrillation" said Dr. Daoud. "Due to the nature of paroxysmal atrial fibrillation it may remain undetected by standard diagnostic methods and may be an under-recognized cause of cryptogenic stroke. With Sleuth AT, we can continuously monitor the patient for AF over a prolonged period to determine if, when and for how long AF is present."

The Long-Term Cardiac Monitoring for Detection of Atrial Fibrillation after Cryptogenic Stroke is a pilot study involving five centers in Canada and the United States. The investigators driving this important clinical study are Dr. Andrew Krahn from the London Health Sciences Centre University Hospital in London, Ontario and Dr. Daoud. The primary endpoint of the study is to determine the incidence of AF at one year from Sleuth AT implantation in patients who have had cryptogenic stroke.

Sleuth AT allows physicians to program the capture of high-quality ECG strips at frequent intervals, providing a new level of insight into complex arrhythmias which are often asymptomatic and frequently changing. These captured ECG strips are automatically transferred to a 24/7 monitoring center, staffed by certified cardiac technicians, who classify and notify physicians of the presence of a wide variety of cardiac arrhythmias such as ventricular tachycardia, bradycardia, supraventricular tachycardia and atrial fibrillation.

"It will be very interesting to see the results that come out of this study" said Dr. Geoff Eubank, a neurologist at Neurological Associates, Inc. in Columbus, who frequently treats cryptogenic stroke patients and partners with Dr. Daoud for evaluation of these patients. "Monitoring and diagnostic technology up until now has been limited and sporadic in providing data. I'm hopeful that the long-term, continuous and automated nature of this system will prove more effective in delivering the information we need to effectively treat these patients and prevent future strokes."

"Having this study underway is a milestone because AF could be the cause of a large number of cryptogenic strokes," said Brian Brockway, Transoma Medical founder and CEO. "AF is a common cardiac arrhythmia that is challenging to manage. However, we believe Sleuth AT is a unique and superior method for monitoring AF and the effects of current and future therapies."

About Atrial Fibrillation and Cryptogenic Stroke

AF is the most common form of cardiac arrhythmia, and a strong independent risk factor for patients predisposed for stroke, heart failure and all-cause mortality. The incidence of ischemic stroke in patients with AF is 2 to 7 times greater than that of people without AF. In an ischemic stroke, blood supply to part of the brain is decreased. This may lead to malfunction of the brain tissue in that area. Stroke without an obvious explanation is termed "cryptogenic"; this constitutes 30 to 40 percent of all ischemic strokes.

Average annual incidence stroke rates vary from 5 percent to more than 12 percent, depending on age and other associated factors. The prevalence and incidence of AF increases with age, and is predominantly a disease of the elderly, particularly those older than 70. The median age of patients with AF is about 75 years, and in individuals 80 years and older, the prevalence is estimated to be 8 percent.

Determining the root cause of stroke is essential to prescribing appropriate secondary prevention, and one of the most important findings in ischemic stroke patients is AF. Detecting AF can be challenging, given that asymptomatic AF, although common, can be difficult to diagnose as a result of its transient nature.

Earlier studies have shown that with conventional methods, AF cannot be detected in all cases, and that a prolonged duration of monitoring may be required to effectively manage stroke patients. The importance that AF was found to have in the etiology and clinical application of stroke patients, spurred many studies that investigated the role cardiac monitoring plays in stroke management. Due to the asymptomatic and transient nature, paroxysmal (sudden onset) atrial fibrillation (PAF) detection does not often occur within the bounds of the admission ECG or 24-hour Holter monitoring; thus, longer monitoring periods were explored. Results showed that longer monitoring periods are likely to increase the yield of new-onset AF.

How Sleuth AT Works

As a complete, remote and automated system, Sleuth AT offers several advantages over other currently available implantable monitoring products. The Sleuth AT Cardiac Monitoring System includes the implanted monitoring device, the Personal Diagnostic Manager (PDM), the Base Station and a 24/7 Monitoring Center operated by Medicomp, a leader in cardiac monitoring with over 25 years of experience analyzing millions of hours of ECG.

-- The Implantable Cardiac Monitor is a small, thin device, about the size of a 50-cent piece (or the size of the smallest pacemakers), which continuously monitors the electrical activity of the heart, the ECG. The cardiac monitor is implanted under the skin during a brief, simple, outpatient procedure.

-- The Personal Diagnostic Manager (PDM) is a hand-held, multipurpose device that automatically retrieves and stores relevant ECG data from the implanted cardiac monitor, securely relays the information to the base station and then to the monitoring center. The PDM is also used by the physician to program the implanted cardiac monitor. Data are collected in three ways:

- Patients who experience symptoms, such as lightheadedness, can press a button on the PDM which tells the system to store the patient's ECG strip during the time of the symptom.

- The system automatically captures and stores the ECG strip when the patient's heart rate is above or below physician-programmed limits.

- The system can be programmed to capture regular ECG strips every 4 hours, 15 minutes or 7.5 minutes

-- At the third-party Monitoring Center, certified cardiac technicians review the patient's ECG data and provide information to the physician to aid in diagnosis and ongoing treatment. Physicians can access this information via a secure Web portal, and have the reports faxed or e-mailed to them as they prefer. If the cardiac technician observes a particularly concerning arrhythmia, the patient's physician will be contacted immediately.

About Transoma Medical

Transoma Medical, Inc., headquartered in St. Paul, Minnesota, is a medical technology company engaged in developing, manufacturing and distributing implantable, wireless diagnostic and monitoring products. Transoma is focused on monitoring systems that provide physicians with vital signs information important to accurately diagnose and monitor various forms of cardiovascular disease, and to optimize drug, interventional, surgical and device treatment alternatives. For more information, visit the company's Web site at http://www.transoma.com.

Source
Transoma Medical

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