The Southern-Norway Post-Stroke Atrial Fibrillation Study

Background and Rationale Atrial fibrillation (AF) is a major risk factor for ischemic stroke, yet it often goes undetected due to its paroxysmal (intermittent) nature. While guidelines recommend prolonged heart rhythm screening after a stroke of undetermined cause, standard hospital practice often relies on short-term telemetry and ambulatory Holter monitoring. These standard methods can be limited by device availability, bulkiness, and short monitoring duration (typically 24-48 hours), potentially leading to under-diagnosis of AF.

This study aims to evaluate the clinical utility and cost-effectiveness of a novel, continuous patch ECG system (ECG247) initiated in the hospital setting compared to standard care.

Study Design This is a prospective, randomized, parallel-group, open-label (no masking) study conducted at a single stroke center. Approximately 450 eligible patients will be enrolled.

Recruitment and Stratification Patients admitted with ischemic stroke or transient ischemic attack (TIA) within the last two weeks are screened for eligibility, aiming for inclusion within 48 hours of admission. Participants are randomized in a 1:1 ratio to either the intervention arm or the standard care arm. Randomization is stratified by age into three groups: 18-64 years, 65-74 years, and ≥75 years.

Intervention Arm (ECG247 Smart Heart Sensor) Patients in this group will have the ECG247 patch applied to the anterior chest wall while in the hospital.

• Device: The ECG247 is a wireless, water-resistant patch sensor that connects to a dedicated smartphone application via Bluetooth. It transmits data to a secure cloud service for analysis.
• Duration: The device is worn continuously for up to 14 days. Monitoring begins in-hospital and continues after discharge.
• Analysis: The system utilizes an algorithm to detect arrhythmia. Episodes of AF >30 seconds are considered positive findings. Study personnel and physicians verify algorithm-detected episodes.
• Concurrent Care: These patients also receive standard in-house telemetry per hospital protocol while admitted.

Control Arm (Standard Care) Patients in this group receive standard heart rhythm monitoring according to current hospital guidelines.

• In-hospital: Monitoring via continuous telemetry or intermittent ECGs based on availability and clinical priority.
• Ambulatory: Upon discharge, patients are referred for ambulatory Holter monitoring. The duration is typically 24-48 hours as decided by the treating cardiologist.
• Analysis: Holter recordings are analyzed by trained technicians and reviewed by a cardiologist.

Biomarker Analysis Blood samples will be collected from all participants to analyze N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels. The study will assess the association between NT-proBNP levels and the detection of silent AF to evaluate its potential for risk stratification.

Outcomes and Follow-up

• Primary Outcome: The detection rate of AF (defined as episodes ≥30 seconds).
• Secondary Outcomes: Time to AF detection, time to initiation of anticoagulation therapy, total monitoring duration, and health economics.
• User Experience: Patients in the intervention group will complete Patient Reported Experience Measures (PREMs) regarding usability and satisfaction.
• Long-term Follow-up: Participants will be followed for up to 12 months to assess clinical endpoints, including secondary stroke, TIA, and major bleeding.

Inclusion criteria

• Patients hospitalized with an ischemic stroke or transient ischemic attack (TIA), including amaurosis fugax, occurring within the last 2 weeks.
• Initial evaluation of CT and/or CT angiography and/or MRI supports a diagnosis of TIA or ischemic stroke.
• Available smartphone and access to the ECG247-app to be able to participate in the study.
• Estimated life span of >6 month
• Permanent address in Norway
• Informed Consent, Capable of giving signed informed consent or consent through proxy as described in Appendix which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in the study protocol.

Exclusion criteria

Participants are excluded from the study if any of the following criteria apply:

Medical Conditions

• Known AF or atrial flutter prior to inclusion
• Concomitant use of anticoagulation therapy or established contraindication to its use. To date this includes apixaban, rivaroxaban, edoxaban, dabigatran, warfarin and indirect thrombin inhibitors (except for short term thrombosis prevention).
• Implanted pacemaker, ICD or loop-recorder
• >70% stenosis of carotid artery on ipsilateral side to the stroke on CT angiography or ultrasound
• Pregnancy