Atrial fibrillation(AF) can be asymptomatic and thus left unidentified in many people, but holds potential risk of lethal complications such as stroke and congestive heart failure. With different screening strategy, the screening result will be different. The longer the monitoring period is, the higher chances AF episodes can be identified, but with greater cost and lower compliance. Therefore, in this study, the investigators want to find the most cost-effective method for AF screening in high risk population with prolonged continuous single-lead ECG device.

We created a score system as to predict AF risk.

1. Age ≥ 75: 2points Age between 65-74: 1point
2. Male: 1point
3. Stroke: Typical symptoms of acute stroke with multiple foci on imaging examination: 5points Typical symptoms of acute stroke with single or uncertain lesion on imaging: 3 points Imaging examination shows old cerebral infarction, transient ischemic attack(TIA), lacunar infarction with clear symptoms: 2points
4. Congestive heart failure: Ejection fraction(EF)≥50%, N terminal pro-brain natriuretic peptide(NT pro-BNP)>1500 pg/mL: 1point EF 40-49%: 2points EF<40%: 4points
5. Echocardiography: Mitral stenosis or regurgitation, aortic stenosis or regurgitation: moderate degree and above: 2points Left atrial anterior-posterior diameter: 40-49mm: 1point Left atrial anterior-posterior diameter: ≥50mm: 2points
6. Vascular disease: History of myocardial infarction, percutaneous coronary intervention(PCI) or coronary artery bypass graft(CABG): 2points Clear history of peripheral arterial obstruction: 3points
7. Hypertension: Blood pressure controlled: 1point Blood pressure uncontrolled(Systolic blood pressure>160mmHg): 2points
8. Diabetic mellitus: Plasma glucose level controlled:1point Plasma glucose level uncontrolled(HBA1c>7):2points i:Chronic kidney disease: estimated glomerular filtration rate(eGFR) 30-49: 1point eGFR <30: 2points j:Sleep apnea syndrome: 1point k:Chronic obstructive pulmonary disease: 1point l:Thyroid disease: 1point

Inclusion Criteria:

• 1.Age between 18-85 2.Score ≥5points in the above scoring system 3.Volunteer to participate in the study

Exclusion Criteria:

• 1.Clear history of atrial flutter or atrial fibrillation 2.History of pacemaker implacement 3.Already on anticoagulation therapy 4.History of severe contact dermatitis 5.ECG recorded by our device unrecognizable 6.Patients with end-stage disease or at advanced stage of cancer with life expectancy less than 1 year

Subjects who holds several risk factors for AF but not yet diagnosed.