Figure 1 Longitudinal mitral annular velocity waveforms obtained using (a) pulse-wave Doppler and (b) color tissue Doppler imaging. A=late diastole, a=annular pulsed-wave Doppler velocity, E=early diastole, HR=heart rate, IVC=isovolumic contraction, IVR=isovolumic relaxation, m=mean color Doppler velocity, S=ejection, and 1 and 2 peak positive and negative velocities . Strain and strain rate curves were extracted from an average of three cycles of tissue Doppler imaging data, using an IBM computer and developmental software (Formtest V6.1; GE Vingmed). Strain and strain rate were derived from strain and strain rate curves obtained by placing a sample bar (12 mm) on six walls in the three apical views. Sampling in the mid-myocardial layer was performed in each segment and maintained at the same position during the cardiac cycle by manually tracking the wall motion, but data were excluded if we were unable to obtain a smooth strain curve or the angle between the scan-line and wall was more than 20°. Peak strain was defined as the greatest value on the strain curve .