Why is the first phase of the pulse from a pacemaker cathodic?


closed as unclear what you're asking by AliceD, fileunderwater, Chris, rg255, user137 Dec 12 '14 at 16:54

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  • $\begingroup$ Welcome to Stack Exchange Biology! $\endgroup$ – L.B. Nov 13 '14 at 20:14
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    $\begingroup$ Do you have a reference to back this up? In general neural implants are tested to see what the most effective pulse phase is. Often one polarity will stimulate the system, while the other inhibits it.Starting with the stimulating phase is deemed best. Then the opposite phase follows to clear the system from the detrimental effects of charge injection. $\endgroup$ – AliceD Nov 14 '14 at 0:52
  • $\begingroup$ Hello Chris, thank you for your answer. but still I could not understand why negative peak is important for the stimulation rather than positive peak. As I can understand from electrochemical reactions, for cathodic stimulation, the energy level of free electrons in the metal are raised. It allows to transfer of electrons from metal to reactant species in solution. $\endgroup$ – Jan Nov 15 '14 at 5:26
  • $\begingroup$ Jan - I don't know which phase is most important either - it depends on the implant system and importantly, on the location of the implant. For example, in retinal implants the active phase depends on whether it is placed sub-retinally (anodic phase most effective) or epi-retinally (cathodic phase most effective). I did a quick search on pace makers and couldn't find anything on it - so please provide me with a citation that says that cathodic-first stimuli are most effective and I'll have a look. Interesting topic! $\endgroup$ – AliceD Nov 24 '14 at 8:09
  • $\begingroup$ BTW: My answer on a related question may be of help to you: biology.stackexchange.com/questions/22020/… $\endgroup$ – AliceD Nov 24 '14 at 11:13