The Valdivia Lab studies the mechanisms that control cardiac function. The main focus is on the regulation of calcium handling in the heart. Our website is still under construction. Come back soon for more information! EC Coupling Excitation-contraction (EC) coupling is the process that converts electrical signals into cardiac contraction. RyR2 RyR2 is one of the largest ion channels. It releases calcium from an intracellular store during EC coupling. Calcium waves Mutations in RyR2 may lead to abnormal cardiac calcium handling and arrhythmia.