1Section of Cardiology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
2Center for Evaluative and Clinical Sciences, Dartmouth Medical School, Hanover, New Hampshire, USA
3Division of Health Services Research, Maine Medical Center, Portland, Maine, USA
4Division of Cardiology, Department of Medicine, Maine Medical Center, Portland, Maine, USA
5Clinical Research Section, Department of Medicine, Dartmouth Medical School, Hanover, New Hampshire, USA
6Division of Cardiology, Beth Israel–Deaconess Medical Center, Boston, Massachusetts, USA;
7Catholic Medical Center, Manchester, New Hampshire, USA
8Eastern Maine Medical Center, Bangor, Maine, USA
9Division of Cardiology, Fletcher Allen Health Care, Burlington, Vermont, USA