Submitted on May 1, 2006
Accepted on May 16, 2006
Spatial frequency content in optical mapping of cardiac cell monolayers
Harold Bien1 and Emilia Entcheva1*
1 Biomedical Engineering, Stony Brook University, Stony Brook, New York, United States
* To whom correspondence should be addressed. E-mail: emilia.entcheva{at}sunysb.edu.
An elegant study by Mironov et al. used experimental data from paced activation in pig hearts to formulate practical resolution limits in optical mapping of cardiac excitation (4). In the examined conditions, little to no content was found >130Hz in the temporal domain and <3mm in space, thereby justifying the use of aggressive filters to improve signal-to-noise ratio with minimal overall distortion (<3%). The remarkably low spatial frequency content was attributed to tissue absorption and photon scattering in thick samples. The authors suggested that in purely two-dimensional systems, such as cultured cardiomyocyte monolayers, higher frequencies might still be obtained. We find that when imaging cell monolayers with very high-resolution detectors (1), the aforementioned interference factors are not present, but surprisingly, the spatial spectra remain similar to those reported for thick tissue indicating factors other than tissue absorption and photon scattering affect spatial resolution.
