The
Cardiomyopathy
Association

People who suffer from heart rhythm disturbances may one day be able to use their own heart cells instead of a pacemaker to correct the problem.

Pacemakers surgically implanted in the chest have traditionally been used to treat disrupted electrical signals in the heart but they need replacing over time. Children who require a pacemaker often need (as they grow) to undergo multiple operations to replace the devices.

Now an alternative to pacemakers may not be far away. Researchers from the Children's Hospital Boston have had success in using an animal's own cells to create electrically conductive tissue in the animal's heart. The researchers took skeletal muscles from rats, along with muscle precursor cells known as myoblasts, and created an electrical circuit that connected the rats' atrias and ventricles.
 
The engineered tissue began beating when electrically stimulated and the implanted muscle cells also began to produce proteins that allowed surrounding cells to electrically connect. Over the lifespan of the rats (about three years) the implants continued to provide an electrical conduction pathway.

The researchers are now working more closely on animals similar in size to a child. Because the technique does not require tissue to be taken from the heart itself, the new technique could be of particular benefit to very small children and babies.

"The advantage of using myoblasts is that they can be taken from skeletal muscle rather than the heart," said the study's lead author Douglas Cowan.

"This will be important for newborns whose hearts are so tiny they cannot spare any tissue for the biopsy--and the muscle cells can go without a good blood supply for a long period of time."

CMA consultant cardiologist Dr Maite Tome said: "Putting permanent pacemakers in children is difficult because they are continually growing and there can be long term complications. "Biological, non-wired pacemakers would be a good alternative if the technique can be fully developed."