sodium-dodecyl-sulfate and Arrhythmias--Cardiac

Scroll waves are prominent patterns formed in three-dimensional excitable media, and they are frequently considered highly relevant for some types of cardiac arrhythmias. Experimentally, scroll wave dynamics is often studied by optical tomography in the Belousov-Zhabotinsky reaction, which produces CO(2) as an undesired product. Addition of small concentrations of a surfactant to the reaction medium is a popular method to suppress or retard CO(2) bubble formation. We show that in closed reactors even these low concentrations of surfactants are sufficient to generate vertical gradients of excitability which are due to gradients in CO(2) concentration. In reactors open to the atmosphere such gradients can be avoided. The gradients induce a twist on vertically oriented scroll waves, while a twist is absent in scroll waves in a gradient-free medium. The effects of the CO(2) gradients are reproduced by a numerical study, where we extend the Oregonator model to account for the production of CO(2) and for its advection against the direction of gravity. The numerical simulations confirm the role of solubilized CO(2) as the source of the vertical gradient of excitability in reactors closed to the atmosphere.

Topics: Algorithms; Animals; Arrhythmias, Cardiac; Biophysics; Bioreactors; Carbon Dioxide; Culture Media; Gases; Humans; Micelles; Models, Statistical; Models, Theoretical; Sodium Dodecyl Sulfate; Surface-Active Agents; Time Factors

The accumulation of lysophosphoglycerides has been implicated as an important biochemical factor for cardiac arrhythmias. Recently, we demonstrated that lysophosphatidylcholine caused cardiac arrhythmias in the isolated hamster heart. In this study, the arrhythmogenic nature of various lysophosphoglycerides with respect to acyl chain lengths and base groups were assessed. We demonstrated that all naturally occurring lysolipids tested were arrhythmogenic at 0.05-0.10 mM. Arrhythmias were also observed with Triton X-100 or sodium laurylsulfate at 0.05-0.10 mM. Our data suggests that no correlation exists between the arrhythmogenic nature of the lysolipids and their critical micelle concentrations. We postulate that arrhythmias are produced by the detergent effect of lysophosphoglycerides.

Topics: Animals; Arrhythmias, Cardiac; Cricetinae; Glycerophosphates; Lysophosphatidylcholines; Lysophospholipids; Mesocricetus; Octoxynol; Phosphatidylethanolamines; Phosphatidylglycerols; Phosphatidylserines; Polyethylene Glycols; Sodium Dodecyl Sulfate; Structure-Activity Relationship