Increased calcium sensitivity in the heart can make for an irregular heartbeaf

"New mouse studies, by Björn C. Knollmann and colleagues, at Vanderbilt Medical Center, Nashville, have uncovered a potential new molecular mechanism to explain why some individuals suffer irregular heartbeats that can cause sudden death. The results suggest a potential new target for drugs that would be beneficial to those at risk. Sudden cardiac death caused by irregular heartbeats (cardiac arrhythmias) is responsible for 10% of all deaths in the US. In some individuals anatomical abnormalities in the heart (such as hypertrophic cardiomyopathy, a disease of the muscle of the heart characterized by a portion of the muscle being thickened) increase the risk of irregular heartbeats and sudden death" - ScienceDaily