The present invention provides apparatus and methods for determining the occurrence of a QRS complex in ECG data. According to an aspect of the present invention, an apparatus is proposed for determining the occurrence of a QRS complex in ECG data by utilizing a first, second and third set of ECG data that are acquired by respectively electrode leads II, V4 and V5 and by determining whether a QRS complex has been detected within the predefined temporal window in at least two of the first, second and third sets of ECG data. According to another aspect of the present invention, an apparatus is proposed for determining the occurrence of a QRS complex in ECG data by utilizing three sets of ECG data whose signal quality values V are the smallest three of the first to twelfth sets of ECG data that are acquired by respectively the standard 12 electrode leads and by determining whether a QRS complex has been detected within the predefined temporal window in at least two of the three sets of ECG data. The two apparatus of the present invention may improve the accuracy of QRS detection, which has been proved by clinical testing.
