During functional reentry, cells in the core of the spiral wave remained quiescent near their resting membrane potential, while cells at the periphery generated full action potentials.
The study provides cellular evidence that the core of a spiral wave reentry in atrial tissue is excitable but nonexcited, with TAP amplitude and duration determined by the source-to-sink ratio.
Transmembrane action potentials (TAPs) were recorded during simultaneous mapping of a reentrant wavefront induced in canine isolated atria. The activation pattern was visualized dynamically using a high resolution electrode catheter mapping system. During functional reentry (spiral wave), cells in the core of the spiral wave remained quiescent near their resting membrane potential. Cells away from the core progressively gained TAP amplitude and duration, and at the periphery of the spiral wave the cells generated TAPs with full height and duration. During anatomical reentry, when the tip of the wavefront remained attached to the obstacle (a condition of high source-to-sink ratio), the TAP near the obstacle had normal amplitude and duration. However, when the tip of the wavefront detached from the obstacle (condition of lowered source-to-sink ratio) the TAP lost amplitude and duration. These results are consistent with the theory that the source-to-sink ratio determines the safety factor for wave propagation and wave block near the core. With decreasing source-to-sink ratio, TAP progressively decreases in amplitude and duration. In the center of the core, the cells, while excitable, remain quiescent near their resting potential. This decrease reflects a progressive decrease in the source-to-sink ratio. TAP vanishes in the core where cells remain quiescent near their resting potential. Functional and meandering reentrant wavefronts are compatible with the spiral mechanism of reentry where block at the rotating point is provided by the steep curvature of the wave tip.
Karagueuzian et al. (Sun,) conducted a other in Reentrant wavefront (spiral wave). Reentrant wavefront induction was evaluated on Transmembrane action potential (TAP) amplitude and duration. During functional reentry, cells in the core of the spiral wave remained quiescent near their resting membrane potential, while cells at the periphery generated full action potentials.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: