Heart rate variability and progression of coronary atherosclerosis - Huikuri, H V; Jokinen, V; Syvanne, M; Nieminen, M S; Airaksinen, K E; Ikaheimo, M J; Koistinen, J M; Kauma, H; Kesaniemi, A Y; Majahalme, S; Niemela, K O; Frick, M H (Arterioscler Thromb Vasc Biol, 1999)