There are many causes of congestive heart failure (CHF) including progressive heart conditions, drug toxicities, infection, and other causes.  Animals in CHF may have respiratory distress from fluid in the lungs or around the heart, a heart murmur, fainting/collapse, shock, or paralysis if a clot has formed.  Procedures to diagnose CHF include thoracic radiographs, echocardiogram, ECG, and blood pressure measurement.

Treatment for CHF is two-fold:
1) Stabilize the animal if it is in congestive heart failure crisis.
2) Maintenance therapy to manage the disease and prevent another crisis. 

Initial therapy is aimed at decreasing the fluid in and around the heart and lungs.  Diuretics and vasodilators may be used; the chest and/or pericardium (sack that holds the heart) may need to be drained physically with a needle.  Long term management may include diuretics and vasodilators to prevent fluid buildup and keep heart rate/blood pressure at a normal level, positive inotropic drugs that improve the ability of the heart to beat, anti-arrhythmic drugs, and dietary management with low salt and weight control.