[1] San Francisco VAMC, Cardiol Div 111C, San Francisco, CA 94121 USA
[2] Univ Calif San Francisco, Dept Med, San Francisco, CA 94143 USA
[3] Kaiser Permanente Med Care Program, Div Res, Oakland, CA 94611 USA
[4] Univ Calif San Francisco, Med Effectiveness Res Ctr, San Francisco, CA 94143 USA
[5] Univ Calif San Francisco, Inst Cardiovasc Res, San Francisco, CA 94143 USA