Aims Approximately 20-25% of strokes are of cardioembolic origin, atrial fibrillation (AF) being a significant cause of cardioembolic strokes. AF is often symptomless and intermittent, making its detection a clinical challenge. Currently the golden standard for diagnosis of AF is by 12-lead electrocardiogram (ECG) or any other ECG-strip.

The primary aim of the study is to assess the potential of chest strap as an ECG monitor especially in arrhythmia detection by cardiologist and algorithm. The secondary aim is to assess potential of photoplethysmography (PPG) based device for arrhythmia detection.

Study design:

Study design will be a prospective case-control study at Kuopio University Hospital (KUH) in Finland. Study material will be collected in internal medicine emergency department at KUH. The study design was approved by University of Eastern Finland ethics committee (347/2018).

Study participants will receive a written information sheet about the study and will be provided with an opportunity to ask questions concerning the study. A written informed consent will be signed by the participants, including a permission to use patient's medical records.

Screening of study participants will be made in participating hospitals from admitted patients in January 2018 - May 2019. The inclusion criteria for study group patients was atrial fibrillation confirmed by a doctor-interpreted 12-lead ECG . Exclusion criteria were: body mass index (BMI) over 35; implanted pacemaker device; 12-lead ECG findings of left bundle branch block (LBBB) or right bundle branch block (RBBB); medical condition requiring immediate treatment that would be delayed by the study measurements; serious infectious disease. Control group consisted of patients with normal sinus rhythm (SR) in 12-lead ECG.

Measurement

Demographics of study patients, including age, gender, previous medical history (as reported by patient or from patient medical records), length and weight , will be recorded.

Before measurements, the patient will be asked to rest for at least 2 minutes, and lay still during the measurements. First, a 12-lead ECG will taken over a period of 10 seconds for rhythm confirmation for study grouping. In the next step, altogether 5 wet electrodes will be attached to patient to record ECG with Faros 360 Holter device (Mega Elektroniikka, Kuopio, Finland) to be used as golden standard for rhythm monitoring. Simultaneously a heart rate monitoring chest strap (Suunto Movesense, Suunto, Vantaa, Finland) will applied to chest approximately 2 cm below the lower end of sternum, according to manufacturer's instructions. PPG-device (Empatica Empatica ltd, Milan, Italy) will be connected to non-dominating wrist. A total of 24 hous recording will be made. The data from heart rate chest strap will sent via Bluetooth connection to study computer; the data from Faros Holter device was recorded to device´s internal memory card and transferred to analyzing software. The data collected was anonymized and ECG data from chest strap and Holter device was analyzed using MATLAB software.

The quality of the ECG-strip will be defined as good (no or only minor artefacts), average (artefacts but QRS complex and/or P-wave identifiable) or poor (major artefacts, no identifiable QRS complex and/or P-wave) by the cardiologist. The rhythm from the ECG-strips was divided to three categories: sinus rhythm, atrial fibrillation or other/inconclusive. The cardiologists also assessed the possibility to detect P-waves from the ECG-strips with SR (yes/no).

The study population will consisted of total 200 patients. According to the initial 12-lead ECG, total 100 patients with atrial fibrillation will be collected, and control group will consist of 100 patients with normal sinus rhythm.

Inclusion Criteria:

Atrial fibrillation in 12-lead ECG and admission to hospital (n=50) Sinus rhythm in 12-lead ECG and admission to hospital (n=50)

Exclusion Criteria:

• BMI>35
• LBBB
• RBBB
• medical condition requiring immediate treatment
• serious infectious disease

Study material will be collected in internal medicine emergency department of KUH