The Merck Veterinary Manual points out that "heart disease includes numerous anatomic and physiologic abnormalities of diverse etiology." Therefore, a brief summary, like those found on PHR about other listed diseases, is not suitable for the vast topic of heart disease and abnormalities. The following websites are offered for more information.
Cardiovascular Anatomy:
www.vetheart.com/anatomy.html
Overview of Heart Disease:
www.merckvetmanual.com/
www.pet-zone.com/
www.avma.org/careforanimals/
Heart disease, with a discussion of the difference between congenital and acquired conditions:
salukihealthresearch
Heart disease, with a discussion of congenital cardiac defects:
www.dpfa.org
Overview of Congenital and Inherited Heart Disease:
www.mesavet.com/library/
www.merckvetmanual.com/
OFA General Cardiac Information:
www.offa.org/
Mitral Valve Disease:
www.upei.ca/
www.dvmnewsmagazine.com/
www.angasstar.com/
Patent Ductus Arteriosus (PDA) can be found in all varieties, but especially the Toys and Miniatures:
www.merckvetmanual.com/
www.geocities.com/
www.lbah.com/Heart/
www.pcoc.net/
Tetralogy of Fallot:
www.merckvetmanual.com/
Endocardiosis And Dilated Cardiomyopathy—The Two Principal Causes of Heart Failure in Dogs, with animation:
www.vetmedin.co.uk/