In my map, every player hears his heartbeat. The more dangerous the situation he's in, the faster the heartbeat, obviously. Fear wares off in time. If memory serves, an average person, when calm, has about 70 heart contraction per minute. We normally hear two successive beats, followed by a longer period of silence. That means that there should be 35 "pairs" of such beats per minute. Right?

What I'm interested in is how to speed up the heartbeat realistically. Is there some universal (that doesen't depend on the contractions per minute) ratio that measures how the wait between the first and the second beat relate to the wait between the second and the first?
(1st)....(2nd)...........................(1st)....(2nd)............................

Or the heart of someone with a high adrenaline level will beat like this: (1st)....(2nd)....(1st)....(2nd)....(1st)....(2nd).... ???

If you know how the heart works, help me out.

i wouldn't consider myself a heart expert, but i am pretty there is no ratio compared to one's heart.

i mean, i'm pretty athletic myself (varsity swimming and water polo) and my first and second beat (the rub dub) have not changed from the (1st)...(2nd).........(1st)...(2nd) effect. The only difference is that my heart can sustain a slower beat under harsher conditions.

I would just make everything proportional and call it good.

(b/70) = (f/a), where b is the number of beats per minute the heart is going at that time, f is the time between contraction and relaxing at that speed, and is the time between contraction and relaxation at average speed (70 bpm). Sort of depends on contractions per minute, but it's easy to find that out. If you just speed up your sound clip, it should work fine.

I could ask my brother later, he has some medical training...

The way the heart works is quite interesting. Basically the hearbeat is automatic, so all the brain controls is the rate at which hearbeats occour.
So all you have to do is record a complete heartbeat and repeat it at a choosen rate to get a realistic result.

Well, it also keeps the separate chambers together... If they were left with their own pacemakers, the atria would go at 70 bpm, and the ventricles at 20 (or it may be the other way around, I forget).

I've tried a deathcounter wait proportion of 4:10 that sounds good enough. Get a bit nervous, I cut it to 3:9, get very nervous and it becomes 2:5. Sounds good to me.

The heart beats faster and faster when stressed: (1st)...(2nd)...(1st)...(2nd) and so on.

Well, mine does. ;p

And I think we mean (lub)...(dub), by the way. Real medical terminology right there, no joke.

Actually... each heartbeat consists of both the lub and the dub. So in a heartbeat of 70bpm, you'd hear 140 thumps per minute, 70 lubs and 70 dubs.

....lub  dub........lub  dub........lub  dub.......
.....1 beat..........1 beat..........1 beat........

Yeah, I figured that out, because the previous setup was just too slow.

An ekg of a regular heart beat:

What you hear is the first bump (p wave) and the spike (qrs complex). When a heart beat speeds up (due to adrenaline or exercise), the time in between heart beats decrease. There is no ratio, just that more adrenaline = faster heart rate.