Heart Rhythm Society
http://www.naspe.org
Information for Patients on Arrhythmias
http://www.naspe-patients.org/patients/index.html
American College of Cardiology
http://www.acc.org
American Heart Association
http://www.americanheart.org/presenter.jhtml?identifier=1200000
General information for patients
http://www.heartinfo.org
PubMed - a service of the U.S. National Library of Medicine and the National Institutes of Health
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi