The aim of this study is to evaluate the reliability of smartphone seismocardiographic detection of AF in comparison to the gold standard of continuous telemetry ECG recording.

In the this case-control study, 300 patients being treated in the wards of Heart Center and Department of Acute Internal Medicine of Turku University Hospital in Turku, Finland between April and September 2017 were included in the study. Patients were assigned to two groups according to the prevalent heart rhythm (sinus rhythm or atrial fibrillation). A smartphone equipped with an inbuilt accelerometer and a gyroscope was placed on the patient's chest to obtain a seismocardiographic recording. Simultaneous telemetry electrocardiography was obtained to assess the reliability of seismographic rhythm recordings. Results will be analyzed to describe the specificity and sensitivity of the method.

Inclusion Criteria for patients with FA:

• ≥18 years of age
• telemetry ECG available
• being treated in Turku University Hospital Heart Center / Acute internal medicine ward
• atrial fibrillation

Inclusion Criteria for patients with sinus rhythm:

• ≥18 years of age
• telemetry ECG available
• being treated in Turku University Hospital Heart Center / Acute internal medicine ward
• sinus rhythm
• gender and age matching pair in FA group

Exclusion Criteria:

• ≤18 years of age
• paced rhythm
• cardioversion during preceding 7 days
• informed consent not signed

Patients treated in the wards of Heart Center and Acute Internal Medicine of Turku University Hospital, Turku Finland between April and September 2017.