Nerve growth run amok may explain why, after surviving a heart attack, some people begin to suffer from irregular heartbeats and may die suddenly when their heart stops beating.
Scientists have known that heart attacks damage both the heart muscle and the nerves that infiltrate the muscle. The electrical signals that trigger the heart to beat are impaired when sent through damaged muscle.
In some people, the disparity between electrical signaling in normal and damaged tissue may be exacerbated when nerves grow back more densely than before, says Peng-Sheng Chen of the Cedars-Sinai Medical Center in Los Angeles. Chen initially looked at the effect of nerve growth on electrical function in the heart because his wife, a neurologist, pointed out that epilepsy can be triggered by abnormal nerve growth. Epileptic seizures are caused by bursts of irregular nerve activity in the brain.