Estimation of 3-D conduction velocity vector fields from cardiac mapping data

A method to estimate three-dimensional (3-D) conduction velocity vector fie lds in cardiac tissue is presented, The speed and direction of propagation are found from polynomial "surfaces" fitted to space-time (x, y, z, t) coor dinates of cardiac activity. The technique is applied to sinus rhythm and p aced rhythm mapped with plunge needles at 396-466 sites in the canine myoca rdium. The method was validated on simulated 3-D plane and spherical waves. For simulated data, conduction velocities mere estimated with an accuracy of 1%-2%, In experimental data, estimates of conduction speeds during paced rhythm were slower than those found during normal sinus rhythm. Vector dir ections were also found to differ between different types of beats. The tec hnique was able to distinguish between premature ventricular contractions a nd sinus beats and between sinus and paced beats, The proposed approach to computing velocity vector fields provides an automated, physiological, and quantitative description of local electrical activity in 3-D tissue. This m ethod may provide insight into abnormal conduction associated with fatal ve ntricular arrhythmias.