1. Department of Cardiology, Kaiser Permanente Northern California 1 , 3600 Broadway, Oakland, CA 94611 , USA
2. Division of Research, Kaiser Permanente Northern California , 2000 Broadway, Oakland, CA 94611 , USA
3. Division of Cardiovascular Medicine, Stanford University , Stanford, CA , USA
4. Department of Cardiothoracic Surgery, Stanford University , Stanford, CA , USA