Short-time nonlinear dynamical analysis of heart rate variability in dogs after acute myocardial infarction

This paper presents the concept of the short-time nonlinear dynamical analysis of heart rate variability for physiological animal experiments and pharmacological experiments as well as clinical diagnosis and prognosis. We established an animal experiment protocol of myocardial ischemia to observe the results of the short-time nonlinear dynamical analysis of heart rate variability and compared the nonlinear dynamical parameters of heart rate variability with the results of myocardial perfusion SPECT under myocardial ischemia. The experiment results on seven dogs showed (1) after acute myocardial infarction the correlation dimension and approximate entropy decreased apparently and gradually increased after 15 days; (2) after acute myocardial infarction the Lyapunov exponent increases and gradually recovery to normal value with time; (3) the developing trends of the nonlinear dynamical parameters were coincident with the SPECT results; (4) from our experiment the correlation dimension is the most sensitive parameter and had a good identity with the results of SPECT image. So we think the short-time analysis of the nonlinear dynamics is a good way to determine gradually increased the degree of the myocardial ischemia and to asses the risk after acute myocardial infarction