1. A method for determining a cardiovascular disease of a user using a wearable device, comprising: receiving, by an electrocardiography (ECG) sensor associated with the wearable device, an ECG signal of the user, the ECG signal corresponding a physical ECG signal of the user; determining a feature set for the ECG signal, wherein the feature set comprises time-domain feature data of the ECG signal and frequency-domain feature data of the ECG signal, the determining the feature set for the ECG signal comprising: determining wavelet coefficients for the ECG signal by performing a wavelet transform to the ECG signal; determining the wavelet coefficients as a first type of the frequency-domain feature data of the ECG signal; determining discrete cosine transform (DCT) coefficients by performing autocorrelation (AC) and DCT to the ECG signal filtered after the wavelet transform; and determining the DCT coefficients as a second type of the frequency-domain feature data of the ECG signal; determining whether the user has the cardiovascular disease based on a similarity between the feature set and reference feature sets of cardiovascular diseases; and on condition that the user is determined to have the cardiovascular disease, reporting to the user that the user has the cardiovascular disease.