in separate hearts , the right atrium was removed to permit examination of both low and high rates ( 167 +/- 2 , 240 , 336 +/- 3 , or 480 beats/min throughout the experiment ) over a wide range of durations of occlusion ( 3 , 5 , 7 , 10 , 15 , 20 , or 40 min ) .
C0018787
hearts
C0225844
right atrium