%0 Journal Article %A G Leech %A N Brooks %A A Green-Wilkinson %A A Leatham %T Mechanism of influence of PR interval on loudness of first heart sound. %D 1980 %R 10.1136/hrt.43.2.138 %J British Heart Journal %P 138-142 %V 43 %N 2 %U https://heart.bmj.com/content/heartjnl/43/2/138.full.pdf