@entity299 (spontaneous, asynchronous contractions of @entity121 ) is the leading cause of @entity204 in the industrialized world, yet it is not clear how it occurs. It has been debated whether or not @entity955 is a random phenomenon. There is some determinism during @entity955 , perhaps resulting from rotating waves of electrical activity. Here we present a new algorithm that markedly reduces the amount of data required to depict the complex spatiotemporal patterns of @entity955 . We use a potentiometric dye and video imaging to record the dynamics of transmembrane potentials at many sites during @entity955 . Transmembrane signals at each site exhibit a strong periodic component centred near 8 Hz. This periodicity is seen as an attractor in two-dimensional-phase space and each site can be represented by its phase around the attractor. Spatial phase maps at each instant reveal the 'sources' of @entity955 in the form of topological defects, or phase singularities, at a few sites. Using our method of identifying phase singularities, we can elucidate the mechanisms for the formation and termination of these singularities, and represent an episode of @entity955 by locating singularities. Our results indicate an unprecedented amount of temporal and spatial organization during @entity299 .

Spatial and temporal organization during XXXX .

@entity204 :: ('MESH:D003643', 'Disease') :: ['death'] @entity121 :: ('MESH:D009135', 'Disease') :: ['cardiac muscle fibres'] @entity955 :: ('MESH:D001281', 'Disease') :: ['fibrillation'] @entity299 :: ('MESH:D006331', 'Disease') :: ['Cardiac fibrillation', 'cardiac fibrillation']
@entity299 :: (MESH:D006331,Disease) :: ['cardiac fibrillation']
