( ( ( ( ( Heart disease ) ( remains ( ( the ( leading cause ) ) ( of ( death ( in ( the ( United States ) ) ) ) ) ) ) ) and ) ( ( ( the burden ) ( of ( heart disease ) ) ) ( continues ( to ( be ( significant ( in ( an ( aging population ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NNP Heart) (NN disease)) (VP (VBZ remains) (NP (NP (DT the) (VBG leading) (NN cause)) (PP (IN of) (NP (NP (NN death)) (PP (IN in) (NP (DT the) (NNP United) (NNPS States)))))))) (CC and) (S (NP (NP (DT the) (NN burden)) (PP (IN of) (NP (NN heart) (NN disease)))) (VP (VBZ continues) (S (VP (TO to) (VP (VB be) (ADJP (JJ significant) (PP (IN in) (NP (DT an) (VBG aging) (NN population))))))))) (. .)))
Heart disease remains the leading cause of death in the United States and the burden of heart disease continues to be significant in an aging population.
(ROOT (S (NP (NNP Heart) (NN disease)) (VP (VBZ is) (NP (NP (DT the) (VBG leading) (NN cause)) (PP (IN of) (NP (NN death))) (PP (IN in) (NP (DT the) (VBN united) (NNS states))))) (. .)))