Pathological blocking of the Autonomous Nervous System (ANS) is diagnosed for patients having Autonomic Neuropathy passing a well-defined set of criteria. In this work, It is shown that standard analysis can be complemented by a study of the chaotic dynamics of the Heart Rate (HR), over a period of 12 min in the resting position. It was found that patients who suffering from ANS blockade, typically exhibit a smaller degree of fractality and complexity of the chaotic attractor reconstructed from the time series of the HR signal. These dynamical measures are more evident in normal human subjects that have been subjected to pharmacological ANS blockade.