The present invention relates to a method for assessing the electrical function of a heart, comprising the steps of:- (1) for each of a plurality of leads of an ECG, determining a value derived from the output of that lead and which corresponds to an action potential duration (2) for each of the plurality of leads of the ECG, determining a value derived from the output of that lead and which corresponds to a diastolic interval (3) for each of the plurality of leads of the ECG, determining a relationship between the determined values for action potential duration and for diastolic interval (3) assessing the differences between the determined relationships for each of the plurality of leads. The invention further relates to apparatus and a computer program that may be used in the method.
