Heart researchers at Rhode Island Hospital led by Dr. Gideon Koren, professor of medicine in the Alpert Medical School, have published two new studies that provide insight into the genetics of arrhythmia and sudden cardiac death. Using a genetic rabbit model they developed in 2008, Koren and his colleagues show in a paper in the Journal of Physiology that heart cells in rabbits with mutations either in a gene called LQT1 or another called LQT2 have different triggers that lead to arrhythmias. In the second study, in HeartRhythm Journal, the group showed that in rabbits with a mutation in LQT2, the sex hormone estrogen can promote arrythmias, while progesterone helps prevent them.