Re: How does pure oxygen affect the heart and its conduction system?

Hi Pat, This is an interesting question. Here in the UK we talk about 
something called 'hypoxic drive' which relates to the fact that our 
respiratory system requires a certain level of C02 to act as a stimulus to 
breathe. The respiratory systems of patients suffering from chronic lung 
tissue diseases, asbestosis etc, use a higher level of hypoxic drive, 
which means that they exist happily on a much higher than normal level of 
carbon dioxide in the blood. If these patients were to be given 02 therapy 
at a doseage higher than 28% their breathing stimulus would be impaired. 
Thus I think the same would aply to a normal heart. Too much O2 must shut 
down the CO2 breating centres which would therefore stop the heart. For 
further reference check out an ambulance manual on oxygen therapy.