Leading causes of death for all Americans: image via AED.com Sudden cardiac arrest (SCA) is an electrical malfunction of the heart. It occurs suddenly, without warning, and is a leading cause of death. Most persons who die of SCA, old and young alike, have never been diagnosed, and 30 percent of them die in their sleep. Scientists at the University of Manchester and the University of Bristol in Great Britain have discovered what happens during sleep to cause suddent cardiac death (SCD), a discovery which may lead to preventative treatments.
The research, led by Professor Henggui Zhang at the University of Manchester, involved detailed computer models showing how gene mutation and activity of the nervous system can combine to disrupt the heart's normal rhythm. The gene mutations particularly affect those with with 'sick sinus syndrome,' and they alter a protein called SCN5A that is involved in generating electrical stimulation for the heart. During sleep, when the pulse naturally slows, the nerve activity of those with this gene mutation may actually cause the heart to completely stop, causing SCD.
The effects of gene mutations can be detected by specialized tests. "We may have to reduce the influence of a certain form of nerve activity on the hearts of sick sinus patients," said Professor Zhang. "This could be via drugs or pacemaker devices."
Professor Jules Hancox from the University of Bristol said: "The insights into sick sinus syndrome from this study are potentially of great importance. If other forms of sick sinus syndrome that involve mutations to different proteins in the heart are affected by nerve activity in the same way, this may identify a common target to reduce or eliminate the risk of dangerous arrhythmia."
The complete results of this study will be published in the journal Circulation Research.