Researchers at NYU Langone Medical Center have discovered several DNA sequence variations behind the electrical impulses that make the heart beat.
The findings may pave the way for a greater understanding of the mechanisms for abnormal heart rhythms and sudden cardiac death.
"This study provides new clues about the biologic pathways that influence cardiac conduction. Our hope is that this information will translate into novel approaches to prevent or treat serious rhythm disorders, including sudden cardiac death," said Glenn I. Fishman at NYU Langone Medical Center.
An international collaboration of scientists identified genetic associations with cardiac ventricular conduction in 22 regions of the genome in the largest study of its kind in conduction.
Some of these genetic variations were found in two sodium channel genes that sit side-by-side on the human genome. Sodium channels are molecular gated pores in living cells that control the flow of sodium ions - electrically charged particles - critical for the heart beat.
The first gene, SCN5A, is well known to be involved in cardiac conduction. The second, SCN10A, has only recently been found in the heart.
The researchers then treated mice with a drug that selectively blocked this sodium channel and found that cardiac conduction was delayed, affecting the ECG.
They also found that a number of other genes and genetic pathways involved in cardiac conduction, including calcium handling processes and transcription factors, which influence cardiac development and formation.
The findings are reported in Nature Genetics.