A monitoring system for measuring QT intervals in patients, the monitoring system comprising: a first monitoring device adhered to a patient at a first location that monitors a first electrocardiogram signal associated with the patient; a second monitoring device adhered to a patient at a second location different than the first location that monitors a second EKG signal associated with the patient; a QT interval measurement module configured to receive the first EKG signal from the first monitoring device and the second EKG signal from the second monitoring device, wherein the QT interval measurement module: identifies first QRS complex attributes based on the first EKG signal, wherein identified first QRS complex attributes include onset of the QRS complex (iRon a) and QRS complex peak (IRpk_a); identifies second QRS complex attributes based on the second EKG signal, wherein identified second QRS complex attributes include QRS complex peak (IRpk b) and T-wave offset (iToff_b); selects qualified beat segments comprised of a plurality of beats suitable for QT interval measurement within the received first and second EKG signals; and measures QT intervals within the qualified beat segments based on the identified first and second QRS complex attributes, based on the equation iQT = ( iRpk_a-iRon_a) + ( iToff_b-Rpk_b), wherein iQT is the QT interval. a first monitoring device adhered to a patient at a first location that monitors a first electrocardiogram signal associated with the patient; a second monitoring device adhered to a patient at a second location different than the first location that monitors a second EKG signal associated with the patient; a QT interval measurement module configured to receive the first EKG signal from the first monitoring device and the second EKG signal from the second monitoring device, wherein the QT interval measurement module: identifies first QRS complex attributes based on the first EKG signal, wherein identified first QRS complex attributes include onset of the QRS complex (iRon a) and QRS complex peak (IRpk_a); identifies second QRS complex attributes based on the second EKG signal, wherein identified second QRS complex attributes include QRS complex peak (IRpk b) and T-wave offset (iToff_b); selects qualified beat segments comprised of a plurality of beats suitable for QT interval measurement within the received first and second EKG signals; and measures QT intervals within the qualified beat segments based on the identified first and second QRS complex attributes, based on the equation iQT = ( iRpk_a-iRon_a) + ( iToff_b-Rpk_b), wherein iQT is the QT interval. identifies first QRS complex attributes based on the first EKG signal, wherein identified first QRS complex attributes include onset of the QRS complex (iRon a) and QRS complex peak (IRpk_a); identifies second QRS complex attributes based on the second EKG signal, wherein identified second QRS complex attributes include QRS complex peak (IRpk b) and T-wave offset (iToff_b); selects qualified beat segments comprised of a plurality of beats suitable for QT interval measurement within the received first and second EKG signals; and measures QT intervals within the qualified beat segments based on the identified first and second QRS complex attributes, based on the equation iQT = ( iRpk_a-iRon_a) + ( iToff_b-Rpk_b), wherein iQT is the QT interval.