There are many reasons why you could suffer a heart attack, from inherited heart disease, stress or an unhealthy lifestyle. (insureye.com)
This problem is most common in big dogs (Rotties, Boxers, Newfoundlands, Goldens, Great Danes etc.) It is the most common inherited heart disease in large dogs. (2ndchance.info)
Subvalvular aortic stenosis (SAS)(frequently shortened to aortic stenosis or subaortic stenosis) is the most common type of inherited heart disease in Golden Retrievers, Newfoundlands, and Rottweilers. (healthypets.mercola.com)