Clinical trial NCT00559988
Conditions: Atrial Fibrillation Atrial Flutter Stroke Embolism, Systemic Arterial Major Bleeding
Keywords: Implanted Cardioverter Defibrillator Cardiac Resynchronization Therapy Defibrillator Home Monitoring Oral Anticoagulation
Sponsor: Biotronik, Inc.
Start date: 2008-02-01; Completion date: 2013-06-01
Enrollment: 2718 participants; Allocation: RANDOMIZED; Intervention model: PARALLEL

Brief summary:
The IMPACT Study will investigate the potential clinical benefit of the combined use of BIOTRONIK Home Monitoring (HM) technology and a predefined anticoagulation plan compared to conventional device evaluation and physician-directed anticoagulation in patients with implanted dual-chamber defibrillators or cardiac resynchronization therapy devices.

Detailed description:
Atrial fibrillation (AF) and atrial flutter (AFL) are common cardiac arrhythmias associated with an increased incidence of stroke in patients with additional risk factors. Oral Anticoagulation (OAC) reduces stroke risk, but because these arrhythmias are frequently intermittent and asymptomatic, start of OAC therapy is often delayed until electrocardiographic documentation is obtained.

Technological advances in implanted dual-chamber cardioverter defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) devices allow early detection and real time verification of AF/AFL with intracardiac electrograms (IEGM) automatically transmitted to the clinicians. Such remote diagnostic capability might be particularly relevant in patients with asymptomatic AF by allowing timely treatment. Compared to conventional periodic, (e.g., quarterly) office device evaluation, daily remote monitoring may prove superior for diagnosis of AF and prophylactic treatment of thromboembolism.

The start, stop and restart of OAC based on a predefined atrial rhythm-guided strategy in conjunction with a standard risk-stratification scheme could lead to better clinical outcomes compared with conventional clinical care. The study is designed to demonstrate a risk reduction of both thromboembolism proximate to episodes of documented AF/AFL and bleeding potentiated by chronic OAC in the absence of AF. Verification of this premise would impact the clinical practice, providing evidence to physicians for the use of HM to guide OAC in patients with AF/AFL. The results of this study should demonstrate the clinical value of wireless remote surveillance of the cardiac rhythm and may define the critical threshold of AF/AFL burden warranting OAC or antiarrhythmic drug therapy in patients at risk of stroke

Arms: arm 1: Home Monitoring is fully enabled and continuous remote surveillance data is available to investigators. Patients will be treated according to a predefined anticoagulation plan, which uses the total duration of AF/AFL combined with patients' CHADS2 score to determine the start, stop, and restart of OAC. arm 2: In Control (Group 2), Home Monitoring is active for Safety Net alerts, but the remote AF/AFL data is not revealed to the patient or treating physician. These patients receive physician-directed OAC consistent with current standards of care.

Safety Net data include:

* ERI/EOS
* Special Implant Status
* Implant in Backup Mode (ROM)
* VT/ VF Detection Inactive
* Emergency Pacing
* 250 Ω \> RV Pacing Impedance \> 1500 Ω
* Symptomatic VT/VF therapies including both ATP and shock
* VT/VF storm
* HM transmission failure \>3 days
Interventions: intervention 1: Home Monitoring Guided OAC intervention 2: Physician-Directed OAC
Intervention descriptions: intervention 1: Active monitoring for atrial episodes through the automatic HM notifications (email, fax, short message service) is required. If the total duration over 48 consecutive hours reaches the predefined anticoagulation condition, and AF/AFL diagnosis is confirmed using the IEGM online, the site instructs the patient by telephone to start OAC. Clinicians continue to monitor patients using HM, and if freedom from AF/AFL reaches the predefined interval, stop of OAC therapy is requested over the telephone. Following stop of anticoagulation, any recurrence of AF/AFL requires restart of OAC therapy.

OAC drugs used: Dabigatran etexilate, Rivaroxaban, Warfarin, other approved VKA intervention 2: Patients will receive physician-directed anticoagulation therapy based on conventional criteria.

OAC drugs used: Dabigatran etexilate, Rivaroxaban, Warfarin, other approved VKA

Protocol documents: