Relating to or denoting a small body of specialized muscle tissue (the sino-atrial node) in the wall of the right atrium of the heart, whose contractions regulate the heartbeat.
- ‘The classical concept of the source of cardiac rhythm is that it originates from the sino-atrial node.’
- ‘Procoralan exclusively reduces heart rate by a specific action on the sino-atrial node.’
- ‘This activity arises not from excitatory nerve fibres, but spontaneously within the heart itself from a small clump of pacemaker cells near the point where the vena cava joins the right atrium: the sino-atrial node.’
Early 20th century: from sinus + atrial (see atrium).