Laplacian electrocardiography. 
This article reviews the recent development in Laplacian electrocardiography.  The Laplacian electrocardiogram was proposed in the early 1990s as an alternative for mapping regional cardiac electrical activity.  Considerable progress has been made in the field during the last 5 years on this emerging technique.  This article attempts to cover both the basic concepts and theory for general readers in biomedical engineering, and state-of-the-art developments in forward and inverse problems of Laplacian electrocardiography, as well as Laplacian ECG mapping in an experimental setting for researchers working in the field of cardiac mapping.  The article also addresses controversies regarding the feasibility of experimentally obtaining the Laplacian electrocardiogram in human subjects.  The work reviewed in this article suggests that Laplacian electrocardiography merits further investigation and promises to provide an important alternative means of assessing noninvasively cardiac electrical activity.