Non-linear dynamics of electrocardiographic waveforms following cocaine administration

We examined dynamics of ECG waveforms preceding and following 10 mg/kg intravenous administration of cocaine in freely moving cats. Cocaine induced substantial variation in ECG waveforms, as demonstrated by non-linear procedures of phase-plane plots and Poincaré analyses. Phase-plane plots revealed that waveform variation following cocaine administration was not randomly or uniformly distributed, but instead followed patterns of clustered organization with unvisited regions. These patterns are characteristic of chaotic distributions, and support the hypothesis that ECG waveform variation following cocaine does not degenerate into random patterns; instead, the variation follows deterministic, though chaotic patterns.