a guinea pig can suffer from a heart attack If it is very overweight . If it is given , too much high starch food in its food , and not enough green stuff and sweet meadow hay it can suffer a heart attack if it is stressed; by being chased by cats or dogs frightened by rats or mice . by being picked up roughly been dropped its hutch in a noisy busy area . It is the responsibility ,of the owner of a guinea pig to understand their needs , and keep them safe and well. here are some good sites ,with some more information for you Guinea Pig Care Free pet care information from The Blue Cross - Britain's pet charity www.allaboutpets.org.uk Keep Guinea Pigs as Pets Everything You Really Need To Know About Pet Guinea Pigs In One Place! SmileyPets.com/GuineaPigsPets {^,,^}