EKG, worried about merging

Question

My humanoids have 2 hearts that are about 5 inches apart in the chest(this is to make room for the 2 aortas to minimize turbulent flow). However on an EKG, the rhythm of the right heart and the rhythm of the left heart might merge and this could be problematic.

For example here is what might show up from A fib of 1 heart when the other heart is at the same heart rate but without any arrhythmia:

You can see that the fibrillation has merged with the normal EKG to form these fibrillatory P waves, fibrillatory QRS complexes, and fibrillatory T waves.

Now granted, this would more likely happen in someone with V fib in 1 heart but it could happen in someone with A fib in 1 heart.

And don't comment on my terrible drawing of an EKG because I know it is terrible. I know I get what look like PVCs and AV blocks and Sick Sinus Syndrome etc. But really I am just trying to get across the sequence of waveforms or that there is fibrillation.

Anyway, this merged EKG would be tough to determine, especially with A fib and V fib since with fibrillation it can be hard to know whether those bigger waveforms are just fibrillation at a higher voltage or whether they are the result of fibrillation merging with the other heart that doesn't have fibrillation(fibrillatory P waves, QRS complexes, and T waves I mentioned earlier).

Asystole of 1 heart + NSR(normal sinus rhythm) in the other heart can look just like the normal synchronized NSR so that is another close call. Though usually the heart rate will be faster if 1 of the hearts is in V fib or asystole than it would otherwise so sinus tachycardia would more likely happen to compensate for the V fib or asystole.

Defibrillation would be much more complicated and they would likely have to do open heart surgery every single time or insert an ICD.

Anyway, how can I avoid merging of the EKG while not having leads directly on the hearts(would lead to a wavy baseline that could easily be mistaken for A fib or atrial flutter) but still keep the 2 circulatory systems my humanoids have? I don't think extra leads is enough.

Answer 1

If the hearts were to be put close together, then their ECG traces would be separate in exactly the same way as the heart ECG of a fetus appears alongside the mother's ECG during gestation in human beings (again, two completely different circulatory systems). In that case, the fetus ECG is at a higher frequency (smaller organism) and lower amplitude than that of the mother.

It is possible to extract the fetal ECG from a single lead abdominal ECG system; however, the typical way to acquire signals in this case is to add more and more electrodes at specific locations to be able to discriminate the different electrical sources in a better way than just a three lead system.

Will there be margin for misinterpretation such as the one described in the question? Yes, but that would be very very small because superposition in a specific direction could be resolved by leads oriented in a different direction.

I am assuming here that the two hearts are supporting different circulatory systems (?) as that makes very good (survival) sense. In that case, it would not be good to put them side-by-side. First of all, a hit at the general area of the heart would take out both organs and that is not very good from a survival point of view. Secondly, you can forget about defibrillation, at least in the classical way because the electrical field would likely affect both organs. But, if you positioned the hearts well apart, that would increase the resilience of the creature and enable the use of current defibrillators developed here on earth to revive them. Except if their heart size is different in which case the defibrillator would need a setting to adjust its power.

Hope this helps.

Answer 2

I think such a being with 2 hearts would have two distinct hearts, in tge same role that we have a double pump in one organ. So the ideas of A-fib and V-fib won’t make sense for these hearts, since they won’t be a pair of double pumps but two distinct simple pumps.

Each heart will have a much simpler pattern of electrical activity. Each can be picked up separately, and interpreting them will be more straightforward.