Heart failure occurs when the heart is unable to pump enough blood for the body’s vital organs to function properly. Heart failure is not a specific disease – instead, it is the result of underlying heart conditions that may be present due to an abnormality of the heart’s structure, ability to contract, or electrical activity.
Congestive heart failure, or CHF, occurs when fluid begins to build up within the lungs (pulmonary edema), in the chest cavity (pleural effusion), and/or in the abdomen (ascites) as a result of heart disease. This congestion causes major organs to function abnormally and/or swell with fluid. Degenerative valve disease in dogs and hypertrophic cardiomyopathy in cats commonly lead to CHF.
Chronic degenerative valve disease (CVD), also known as endocardiosis, is the most common type of heart disease in dogs. It occurs when the heart valves, which control blood flow between the chambers of the heart, become thickened and inflexible. Their distorted shape prevents the valves from shutting properly. Blood then leaks through the abnormal valves resulting in backflow, leading to increased pressure within the heart chambers or blood vessels. This condition commonly affects the mitral or tricuspid valves and is also known as myxomatous valve degeneration.
In some dogs, progressive degeneration of the heart valves leads to fluid buildup in and around the lungs and in the abdomen. The fluid buildup as a result of impaired heart function is known as congestive heart failure.
The term “cardiomyopathy” is used to describe diseases that affect the heart muscle. Dilated cardiomyopathy (DCM) is an acquired disease resulting in an enlarged heart due to the thinning of the heart muscle. As the heart muscle stretches and weakens, the inner chambers become dilated which decreases the heart’s ability to contract and pump blood properly. Heart valves, which control the blood flow between the chambers, may leak because the heart takes on an abnormal shape. Leaky valves plus poor heart muscle contraction cause a buildup of fluid in and around the lungs and in the abdomen. The fluid buildup as a result of impaired heart function is known as congestive heart failure.
When veterinarians talk about heart sounds, they are referring to those that can be heard with a stethoscope during a physical examination.
A normal heart has two distinct sounds, described phonetically as lub, the first heart sound, and dub, the second heart sound. The first heart sound is the closure of the valves between the top and bottom chambers of the heart, the atria and ventricles. The second heart sound is the closure of the valves controlling blood flow in and out of the heart.
A phonocardiogram is a special recording of heart sounds. This is a recording of a normal dog heart made with a digital stethoscope.
Normal heart sounds
While cats are famous for their ability to land on their feet, the reality is they don’t always stick their landing. High rise syndrome refers to the common set of injuries that cats may sustain when they fall from high places. This condition is seen more often in warmer weather, but high rise syndrome can occur anytime a window or balcony door is left open.
Cats love to sit on windowsills and watch the birds fly by. If a window is open too wide or if they push on a loose screen, they can fall out. Cats might also fall if they are startled by a vacuum or other loud noise.
In the 1980s, the Animal Medical Center became the first to report on high rise syndrome when, over the course of five months, AMC treated 132 cats who had fallen from buildings. Although 90 percent of the cats survived, many of the cats sustained serious injuries, including chest trauma, head/facial injuries, and limb fractures.