sentences:  Sinoatrial nodal artery
  
  The sinoatrial nodal artery (or sinuatrial nodal artery or sinoatrial artery) is an artery of the heart which supplies the sinoatrial node, the natural pacemaker center of the heart, and arises from the right coronary artery in around 60% of people.In about 40% of cases, the sinoatrial artery is a branch of the left circumflex coronary artery.