During their obstructive episode, the heart muscle must pump harder to circulate the blood.
(the heart muscle; must pump harder; to circulate the blood; T:During their obstructive episode) Context(the heart muscle must pump harder,List([34, 67))):(the heart muscle; must pump harder to circulate; the blood)
the heart muscle must pump harder,List([34, 67))
the heart muscle the heart muscle
must pump harder must pump harder to circulate
to circulate the blood T:During their obstructive episode
the blood