Essential for maintaining normal cardiac rhythm in the developing heart and for neonatal survival (PubMed:33597309). Inhibits potassium and calcium currents in the cardiomyocytes, this assists in timely action potential repolarization and thereby maintains normal cardiac rhythm (PubMed:33597309). Knockout mice are perinatal lethal and isolated embryonic cardiomyocytes exhibit arrhythmic calcium oscillations. Belongs to the TMEM161 family.