For additional information on heart and vascular diseases, visit some of the following Web sites:

American Association for Thoracic Surgery
www.aats.org

American College of Cardiology
www.acc.org

American Heart Association
www.americanheart.org  

Heart Rhythm Society (formerly the North American Society of Pacing and Electrophysiology)
www.hrsonline.org  

National Institutes of Health (NIH)
www.nih.gov

Society of Thoracic Surgeons
www.sts.org