Earl E. Bakken:
Transcript of Interview 2 Excerpt
Earl Bakken, interviewed by David Rhees, on September 11, 1997 in Fridley Minnesota.
“I think it [the pacemaker] was probably one of the first really commercial uses of transistors. Of course, operating at such low currents and low voltage and everything, we felt they were very safe. But we burned them in for thirty days when we built them.
We loaded them with a 1,000-ohm resistor because I figured that heart impedance, at least from the resistance standpoint, was about 800 ohms, was the best we had tested. So I used a 1,000-ohm resistor as a test load, and that’s what the dial was calibrated into, 1,000-ohm. Well, they’re not now, but we did that at the first and calibrated into 1,000 ohms.
Cordis, when they came out with theirs, they went a different way. They used a 500-ohm load. So that means, when you had the same battery, they had twice the current, and so they marketed their pacemakers as having a higher output than ours, and into the same load, they’d have exactly the same current.
So we had to quickly settle on something that we all used. General Electric came out using 330 ohms, and that’s when we got together through AAMI [American Association of Medical Instrumentation] and settled on a 510-ohm load.”