Re: After separated from the body, how long will the human heart beat?

Hello Jay!  Thank you for your question.

***DO NOT TRY THIS AT HOME***   :)

If it were ethically and legally possible to cut someone open and remove 
their heart for the heck of it, the heart would truly beat for only a few 
seconds.  This is because the tissue starts to die as cells are deprived of 
oxygen and the electrochemical gradient across the membranes are disrupted. 
Atrial and ventricular fibrillation will continue for maybe 3-5 minutes 
more, but fibrillations do not look like true heartbeats that one would see 
in a movie (ex. Indiana Jones and the Temple of Doom, where the evil guy 
rips out the other guy's heart and it beats away like crazy).  
Fibrillations are disorganized electrical impulses scattering throughout 
the heart.  These are really cool to see --- they move like little ripples 
along the heart. 

Now, what I just described above assumes you took the heart out and just 
left it sitting on a table somewhere.  The heart can survive for longer 
periods of time outside the body if conditions are carefully controlled.  
During transplants, for example, the heart is not only kept on ice (or iced 
saline), but it is perfused with a special solution (very cold as well) 
containing adenosine, magnesium sulfate, potassium, starches, sugars... 
this solution helps to maintain cell viability so that the heart will 
survive to function properly upon implantation.  Administering the cold 
preservation solution to the heart stops the heart from beating, which is a 
good indicator of how well the heart is preserved.  If, during 
implantation, the new heart starts to beat a little before surgeons are 
finished sewing it in (it may be warming up from the surgery lights aimed 
on it), the surgeons may apply some more iced saline directly onto the 
heart or run another bag of preservation solution to cool it back down.  
Organ preservation solutions, as amazing as they are, are still only a 
temporary means of protecting the cells and tissue.  That is why during 
transplants, even though the heart is protected by the cold environment and 
the preservation solution, the donor team (they go to retrieve the healthy 
organ) still moves very quickly, very efficiently, as they only have a few 
hours to excise the donor heart and get it to the recipient before it is no 
longer viable.   ***For information on preservation solutions, check out  http://users.surgery.wisc.edu/~southard/uwsolution.html   This solution, 
UW, is one of the most widely used preservation solutions***

Just for an interesting tidbit, there is a very common technique for 
researching organs removed from the body called the Langendorff model.  
Basically, you perfuse organ you're interested in (let's use the heart for 
now) with your particular preservation solution, completely cut out the 
organ from the body, and connect it to this Langendorff apparatus.  This 
setup is made up of a complex system of plastic tubing, pressure 
transducers, a reservoir of preservation solution, a place for oxygen to be 
added to the preservation solution, bubble traps (don't want to pump air 
into the coronary arteries or create an air lock in your tubing), filters, 
flowprobes, a roller pump for moving the preservation solution through the 
tubing, and a little place to connect your excised heart to the system.  
Often, researchers will crush the SA node (the natural pacemaker of the 
heart) and connect their own pacing wires to the heart so that they can 
control the heart rate for their study (this is useful in studying the 
heart, because changes in rhythm can alter the particular data you're 
collecting).  The heart can continue beating for a few hours completely 
removed from the body via this setup.  Even after a few hours, though, the 
heart begins to contract out of synch with the pacing, and it eventually 
dies simply because of the artificial environment it is in (a happy heart 
would much rather be in someone's chest).  ***For information on the 
Langendorff model, check out www.quantametrics.com/exp-prod05b.htm and 
www.kentscientific.com/2000updatedpages/28.html  These sites show diagrams 
of Langendorff setups and how the heart connects to them.

Hope this information is helpful to you.  Feel free to email me at 
monreal.1@osu.edu if you have more questions.

Sincerely, 
G. Monreal