RT Journal Article SR Electronic T1 Resting heart rate: what is normal? JF Heart JO Heart FD BMJ Publishing Group Ltd and British Cardiovascular Society SP 1048 OP 1049 DO 10.1136/heartjnl-2017-312731 VO 104 IS 13 A1 David Nanchen YR 2018 UL http://heart.bmj.com/content/104/13/1048.abstract AB