A method for detecting long QT syndrome in a subject comprises obtaining datacorrespondingto an electrocardiogram (ECG) signal of the subject, identifying a set offeatures in the data based onselected inflection points of the ECG signal, using the set of features tocategorize segments of the ECGsignal, and using the categorized segments of the ECG signal and theinflection points to classify the ECGsignal as normal or as long QT syndrome. Long QT syndrome is detected when thesubject's ECG signal isclassified as long QT syndrome. The method may include determining whether thelong QT syndrome isType 1 or Type 2.