Fig. 4: An overview of the case selection procedures for Center-A, Center-B, and Center-C.

Center-A: the ECG Division in the Cardiovascular Outpatient Department at Guangdong Provincial People’s Hospital; Center-B: the ECG Division in the Cardiovascular Inpatient Department at Guangdong Provincial People’s Hospital; Center-C: the ECG Division at Shengjing Hospital of China Medical University. The descriptions within the blue boxes provided the reasons for omitting some cases (with ECG data and diagnostic results).