14 new genetic variations tied to heart rate identified

Scientists have identified 14 new genetic variations that are associated with heart rate and may provide insight into the treatment of cardiovascular disease.
The study led by researchers at the Icahn School of Medicine at Mount Sinai in New York and the Medical Research Council Epidemiology Unit in Cambridge, UK, through a collaborative genome-wide study on individuals discovered the new genetic variations linked to heart rate.
Senior author of the study Dr Ruth Loos from Mount Sinai and her team, spent three years working on a genome-wide association study using data from 181,171 participants from 65 studies during 2009-2012.
"Without any prior hypothesis, we studied the entire human genome hoping to identify new genetic variations that no one before had even imagined would play a role in the regulation of heart rate," said Loos.

"This discovery is just the beginning of something new and exciting and can hopefully be used to identify new drugs that can be used for the treatment of heart rhythm disorders," Loos said.
In a follow-up study, experimental down-regulation of gene expression was then conducted on fruit flies and zebra fish, to better understand how genetic variations might affect heart rate.

These experiments identified 20 genes with a role in heart rate regulation, signal transmission, embryonic development of the heart, as well as cardiac disorders, such as dilated cardiomyopathy, congenital heart failure and sudden heart failure.
"Our findings in humans as well as in fruit flies and zebrafish provide new insights into mechanisms that regulate heart rate," said Dr Marcel den Hoed, post-doctoral fellow at the Medical Research Council Epidemiology Unit and lead author of the study.

The follow-up study also showed that a genetic susceptibility for higher heart rate is associated with altered cardiac conduction and a reduced risk of sick sinus syndrome, a common indicator for pacemaker implantation.
"Our study tripled the number of genetic variations that are known to be associated with heart rate, some of which are also associated with other cardiovascular risk factors and with heart rhythm disorder," said Loos.
The study was published in journal Nature Genetics.