2. Materials and Methods

A Power Lab System (AD Instruments, Australia) was used for heartbeat recordings. For human EKGs, (abbreviation after Willem Einthoven), commercially available EKG electrodes were used. They are available worldwide, for example, a set of ready-made three AgAgCl electrodes (Vitrode V, Nihonkoden Co. Ltd. Tokyo). EKG signals were transferred to a Power Lab System. Finger pulse recordings were also used with it. For crustacean model animals' EKG, permanently mounted metal electrodes were used—they were glued on the carapace. The metal electrodes, + and –, were reaching the surface of the heart through small holes made on the carapace. All subjects and specimens were treated as per the ethical regulations of Tokyo Metropolitan University.

2.1 Data Acquisition and Ethics

2.2 The Healthy Heart and Its Scaling Exponent

2.3 Animal Models

2.4 The Heart Science History

2.5 Evolution of the Heart

2.6 Peng's DFA

2.7 DFA Programs

2.8 mDFA

2.9 Box

2.10 Processes in DFA and mDFA

2.11 Scaling Graphs