On Sunday, researchers said they had identified more than a dozen genes that help modulate heart rate, a finding that one day may lead to smarter cardiac drugs.
Three teams, working separately, netted the genes after comparing the DNA codes of tens of thousands of people of European and Indian descent.
The genes control electrical impulses that drive the muscles in the cardiac pump. These signals are transmitted by specialised proteins in muscle cells called ion channels.
People with different variants of the genes can be more -- or, alternatively, less -- at risk of heart flutter and other rhythm problems, according to the authors, publishing in the journal Nature Genetics.
The studies were carried out by deCODE Genetics of Reykjavik, Iceland; Imperial College London; and the Helmholtz Zentrum Muenchen, Germany.
Heart disease accounts for more than almost seven million deaths a year, half of them through abrupt changes in rhythm, such as a condition called ventricular fibrillation.