Is fibrillation chaos?
 Ventricular fibrillation is examined to determine whether it is an instance of deterministic chaos.
 Surface ECGs from dogs in fibrillation were used to generate a state space representation of fibrillation.
 Our analysis failed to identify a low-dimensional attractor that could be associated with fibrillation.
 The results suggest that fibrillation is similar to a nonchaotic random signal.
 We note, however, that such random-looking but nonchaotic behavior can also be generated by a nonlinear deterministic system.
