Developments in mobile healthcare result in wide use of mobile phones to acquire, store or analyse mobile users' biosignals, such as the electrocardiogram (ECG). These activities have motivated global research in designing new QRS-complex detectors and delineators for single-lead ECG signals. This paper examines a QRS detection and delineation algorithm based on a Euclideandistance calculation in the phase space constructed with the derivative rule. The results confirmed that the phase-portrait constructed with the derivative rule is suitable for the QRS detection and delineation of the ECG signals, delivering comparable results to other established algorithm, such as Pan-Tompkins [16].