Electrocardiogram data is received in association with a subject, the electrocardiogram data comprising a series of RR intervals and a series of QT intervals. A first value which indicates an amount by which uncertainty associated with the QT intervals is reduced given the RR intervals is generated. A second value which indicates an amount by which uncertainty associated with the RR intervals is reduced given the QT intervals is generated. The subject is determined to be associated with a low risk of cardiac dysfunction responsive to the first value exceeding the second value and a result of the determination is provided.