Delay in cardiac repolarization causes ventricular tachyarrhythmias as well as Torsade de pointes (TdP). A feature of TdP is pronounced prolongation of the QT interval in the supraventricular beat preceding the arrhythmia. TdP can degenerate into ventricular fibrillation, leading to sudden death. Thus QT interval measurement and regular verification of the interval is important for analyzing cardiac health. A novel and simple approach to determine the duration of ventricular repolarization, i.e. QT interval of a recorded ECG wave is proposed here. Here a fully automatic method for measurement of QT interval is proposed, i.e. by five-point differentiation of ECG data and noting the slope change of the resulting graph. Points with zero slopes were considered as the end of respective waves. The algorithm is tested with physionet database. So this thesis contains the basics of ECG DATA ANALYSIS in the TIME PLANE with MATLAB based Programs and results all based on the 2006 Challange of Computers in Cardiology now called Computing in Cardiology (http://www.cinc.org/. It is benifical for the firstimers working in ECG Signal Processing.