Proceedings of The Physiological Society

University of Oxford (2011) Proc Physiol Soc 23, C76

Oral Communications

Mapping of cardiac activation with electrode arrays of monophasic action potential in vivo and in vitro

Z. Shui1,2, H. Xiao1, M. Boyett1, J. Liu2, K. Liu2, X. Yang2, H. Wang2, Y. Du2

1. Cardiovascular Research Group, School of Biomedicine, University of Manchester, Manchester, United Kingdom. 2. Departments of Cardiovascular Surgery and Cardiology, Union Hospital, Huazhong University of Science and Technology, Wuhan, China.

  • Figure 1. A map of MAPs between superior vena cava and right pulmonary veins in the rat heart perfused physiologically in vitro

Background — Optical mapping has been used to study action potential and its propagation for long time. However, it cannot be utilized in vivo and/or in working heart due to its technical limitations such as the application of excitation-contraction uncoupler and its side effects. In general, excitation-contraction uncoupler (for example, BDM or Cytochalasin D) not only stops normal sinus rhythm and heart beating, but also causes abnormal action potential and conduction (Cheng et al. 2004; Hayashi et al. 2003). Methods and Results — We have currently developed a multi-electrode array system for mapping of monophasic action potential (MAP). The system consisted of two 9×9 MAP-electrode arrays (0.5×0.5 and/or 1×1 cm) and computerized data acquisition and analysis, which was able to synchronously record the MAPs at two regions in vivo and/or in working heart perfused physiologically in vitro and in situ (Hao et al. 2009). A catheter electrode array of MAP was also developed, which was successfully used to record the MAPs in canine hearts. The animal protocols were in accordance with Home Office regulations and Chinese rules. Adult rats were stunned and killed by the cervical dislocation, whereas adult rabbits were killed with an overdose of pentobarbitione. Adult canines were anesthetized with morphine (2 mg/kg) and alpha chloralose (100 mg/kg) and ventilated by a respirator. A recording sample from one MAP array is shown in the figure. Conclusions — The main advantage of this system is that mapping of cardiac activation can be carried out in normal working heart. Based on the application of catheter MAP electrode array, it is also considerable and feasible in clinical studies and practices.

Where applicable, experiments conform with Society ethical requirements