Optimal designs in electrocardiography with non-constant variances

Kurzfassung/Abstract

For medical diagnosis it is important to have information about the electrical potential of the heart of a patient. Body surface potential mapping (BSPM) is the representation of electric potentials as they occur at a fixed point of time on the body surface during the electric activity of the heart. It has been demonstrated in {\it M. Hirai} et al. [Am. Heart J. 108, 975-982 (1984)] that, in fact, the BSPM produces valuable information to the physician typically not obtainable from the ECG. Using the method of cylindrical regression for the representation of the potentials, the determination of optimal designs in the authors' paper, Innov. Tech. Biol. Med. (ITBM) 8, 23-34 (1987), is based on the assumption that the (random) potential values measured on the body surface have constant variances. According to the decentral position of the heart we suppose here that the variance of the potential deviation depends on the distance between the measuring points and the heart.