>> I still find it astonishing that they can build an amplifying powerful 
>> enough and sensitive enough to detect the absurdly small electrical 
>> currents, diluted across vast distances in space, and yet *not* pick 
>> up the sea of EM interference in the room... Pretty amazing stuff!
> 
> EM (if you mean computers, mobile phones etc) is not the problem 
> generally, mains power supply is.

Yeah, I guess most EM is too high-frequency to interfere with the 
signals of interest... (A normal heatbeat is, what, a few Hz?)

>> No. I'm just curios. (Personally I wouldn't even know a T wave from a 
>> U wave...)
> 
> The T is the slow part after the QRS, the fast part with the highest 
> excursions. The U wave may be after that. It is not present in every 
> lead and not in every person. Frankly, no one knows what generates it.

I find it... uh... "interesting" how many medical effects nobody 
understands. Like, apparently nobody actually knows why menthol works. o_O

>> Sure. But I'd imagine you still need to shave your head to get them 
>> anywhere near your scalp.
> 
> No. small electrodes fitted with conduction glue like material IIRC

...which is what I was expecting for the ECG. But apparently not.

>> Yeah - the soft, tender part in your elbow. What, they couldn't find 
>> anywhere more painful? :-S
>>
> Ah, it seems we have found a biological abnormality here. FYI, in most 
> people the density of nerve endings in the elbow is much less tjan in 
> the fingertips.

See my other reply. Fingertips have to be tough. Elbows don't.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

Post a reply to this message