Have a Heart....

Great website for ECG practice!
http://www.skillstat.com/about.htm

ECGSIM is an interactive simulation program that enables one to study the relationship between the electric activity of the heart and the resulting potentials on the thorax: PQRST wave forms as well as body surface potential maps:
http://ecgsim.org/

Cardiovascular Physiology:
http://www.gwc.maricopa.edu/class/bio202/Cardiovascular/index.htm
http://www.cvphysiology.com/

Cardiac Dysrhymias:
http://breeze.mc.maricopa.edu/p65735599/

Interpreting 12 lead EKG's:
http://www.12leadecg.com/intro/

Heart Sounds:
http://www.openheartsurgery.com/heart_murmur.html

virtual stethoscope:
http://sprojects.mmi.mcgill.ca/mvs/

EKG tracings:
http://homepage.mac.com/edutainment/PhotoAlbum6.html
http://www.ecglibrary.com/ecghome.html
http://themdsite.com/
http://library.med.utah.edu/kw/ecg/index.html

Let's Play Operation! A fun game that walks you through a heart transplant:

http://www.pbs.org/wgbh/nova/eheart/transplant.html

Great tutorial on blood pressure and cardiac output. If you peruse the site, you will also find information on the heart itself and blood vessels:
http://www.biosbcc.net/doohan/sample/htm/COandMAPhtm.htm