normal sinus rhythm (NSR) [L, norma, rule, sinus, hollow; Gk, rhythmos] , the normal heartbeat initiated by the pacemaker in the sinus node, with a heart rate of 60 to 100 beats/min.
normal sinus rhythm (NSR) [L, norma, rule, sinus, hollow; Gk, rhythmos] , the normal heartbeat initiated by the pacemaker in the sinus node, with a heart rate of 60 to 100 beats/min.