With its ability to onset at any age, in any breed or gender, congestive heart failure (CHF) is one of the most serious canine and feline heart conditions. Congestive heart failure is characterized by the heart’s inability to circulate enough blood to meet the body’s demands. Because a heart muscle becomes weakened by CHF, the health of other organs suffers, including that of the liver, kidneys, and lungs.

CHF can be caused by the left, right, or both valves interrupting blood flow and causing blood to back up. Left side valvular disease occurs when blood accumulates in the lungs or abdomen, though this is less common in cats. Right side valvular disease arises when blood has collected in the vena cava and jugular vein, which causes the heart to pump faster and work harder; this eventually causes the heart to enlarge, forcing the heart’s internal chamber capacity to decrease, which means less blood can be pumped out. This entire consequence is cyclic, again causing the heart to work harder and continue to enlarge.

A pet with congestive heart failure can continue to function normally for months, even years, without exhibiting any outward signs of something being wrong; therefore, it can be difficult for an owner to tell that a serious cardiovascular condition exists.

Early signs of congestive heart failure:

• Bloating
• Coughing during increased activity
• Decreased activity level
• Easily tiring
• Fainting
• Lack of appetite
• Pacing and restlessness before bed
• Rapid breathing
• Unexplained weight loss

Diagnosis of congestive heart failure

Identifying the cause of congestive heart failure is often an involved process. Diagnosis begins with a full physical examination, during which the veterinarian can find key indicators of congestive heart failure, including a scratchy sound in the lungs when breathing or a subdued sounding heartbeat. Following the physical, there are several tests the veterinarian may perform:

• Blood pressure measurement – high blood pressure suggests CHF
• Echocardiogram (ultrasound of the heart) – allows the veterinarian to visualize valvular deformities, cardiac muscle-wall thickening, and valvular leakage
• Electrocardiogram – measures electric impulses of the heart