The heart is organ responsible for pumping blood and distributing oxygen to the body's tissues. The right side of the heart pumps out blood which travels to the lungs and becomes oxygenated while the left side receives blood (already having oxygen from the lungs) and pumps it back into the aorta chamber of the heart. The pumping chambers of the heart are called ventricles.
Feline Hypertrophic Cardiomyopathy is a disease where the heart muscle of the left ventricle thickens (hypertrophy). The interior of the left ventricle may get smaller and less blood can be accumulated because of it. If the ventricle walls stiffen and contract, they will impair the heart's ability to fill with blood. During the diastole (relaxation period), if the ventricle cannot sufficiently relax, a build up of blood will occur causing the backup in the blood vessels of the lungs. [...]