This is a prospective, observational clinical study with150 patients of persistent AF (trial group 1), 150 patients of paroxysmal AF (trial group 2), and 150 healthy subjects (control group). The trial is divided into two parts. The aim of first part is to evaluate the sensitivity and specificity of magnetocardiography on diagnosing persistent AF, and the second part is to evaluate the independent predictors of magnetocardiography on predicting recurrence of paroxysmal AF. The patients who had been diagnosed with AF in OPD or IPD will be included. After signing the informed consent letter, medical history of all subjects will be collected, including magnetic cardiogram, 12-lead electrocardiogram, holter electrocardiogram, cardiac ultrasound and blood tests. Patients with paroxysmal AF will be followed up for 3 months, and the recurrence of AF is the observation end point.

Group: Group 1 (Persistent AF)

Inclusion criteria：

• Persistent AF is recorded by ECG before the examination of the magnetocardiogram;
• Detailed clinical records, including medical history, cardiovascular risk factors, blood tests, and antiarrhythmic drug therapy;
• It is recommended that antiarrhythmic drugs be discontinued at least 5 days before the examination and continue if atrial fibrillation occurs or the symptoms of atrial fibrillation are obvious;

Exclusion criteria:

• Severe valvular heart disease, structural heart disease, heart function classification ≥ New York Heart Association functional class II, history of ischemic heart disease, left ventricular ejection fraction < 50%, hyperthyroidism, primary pulmonary hypertension, and respiratory disease;
• Patients after radiofrequency ablation;
• The implanted devices in the body effect the magnetic signal during the detection process, such as prosthetic limbs, heart stents or valves contain metal material.
• Unable to maintain the supine position during the examination.

Group: Group 2 (Paroxysmal AF)

Inclusion criteria:

• Persistent AF is recorded by ECG before the examination of the magnetocardiogram;
• Detailed clinical records, including medical history, cardiovascular risk factors, blood tests, and antiarrhythmic drug therapy;
• It is recommended that antiarrhythmic drugs be discontinued at least 5 days before the examination and continue if atrial fibrillation occurs or the symptoms of atrial fibrillation are obvious;

Exclusion criteria:

• Severe valvular heart disease, structural heart disease, heart function classification ≥ New York Heart Association functional class II, history of ischemic heart disease, left ventricular ejection fraction < 50%, hyperthyroidism, primary pulmonary hypertension, and respiratory disease;
• Patients after radiofrequency ablation;
• The implanted devices in the body effect the magnetic signal during the detection process, such as prosthetic limbs, heart stents or valves contain metal material.
• Unable to maintain the supine position during the examination.

Group: Control group

Inclusion criteria:

• No history of AFor other arrhythmias;
• Detailed clinical records, including medical history and cardiovascular risk factors;

Exclusion criteria:

• severe valvular heart disease, structural heart disease,heart function classification ≥ New York Heart Association functional class II, history of ischemic heart disease, left ventricular ejection fraction < 50%, hyperthyroidism, primary pulmonary hypertension, and respiratory disease;
• The implanted devices in the body effect the magnetic signal during the detection process, such as prosthetic limbs, heart stents or valves contain metal material.
• Unable to maintain the supine position during the examination.

Patients with atrial fibrillation and healthy people without arrhythmia