Go for its Blood test.

‘Heart problem’ in your pet is a silent killer. You have to closely watch your pet if it shows the signs of lethargy, wheezing, croupy coughing or it gets tired with little exercise.
Its enlarged heart can’t be detected with a stethoscope.

Significant heart disease can be present and undiagnosed by your veterinarian long before your pet shows clinical symptoms of illness.

Too many pet owners too often find themselves in this heartbreaking situation.

Both dogs and cats are at risk for heart disease, and both can develop either type:
1. Heart muscle disease
2. Valvular disease

Cardiomyopathy is the scientific term for an enlarged heart muscle.
Some breeds of dogs are predisposed to the condition, including New Foundlands, Great Danes and Dobermans.

Cardiomyopathy can also be caused by a dietary deficiency. The amino acids taurine and carnitine are critical for normal heart development and performance. If your dog’s or cat’s diet is lacking in these amino acids, heart muscle damage can result.
Poor valve health can also lead to heart disease. A leaky valve makes your pet’s heart work harder, and the harder it works, the bigger it gets. Valve disease leads to congestive heart failure in both dogs and cats.

Heart murmurs (which are usually present when there are valve problems) are ranked on a scale from 1 to 6, where 1 is considered mild and 6 is the worst case.

Leaky valves or heart murmurs are frequently seen in predisposed breeds like the Cavalier King Charles Spaniel.
Leaky valves are also found in aging pets and animals with some metabolic conditions like feline hyperthyroidism.

If your veterinarian suspects a heart problem – usually by hearing a murmur through a stethoscope, by doing a physical examination, and/or by considering symptoms your dog or cat is experiencing – diagnostic tests will be required to confirm presence of disease.

These tests, usually x-rays, EKG or cardiac ultrasound, can cost several hundred dollars.

For many pet owners who want to be proactive in detecting heart disease in a dog or cat, the expense of these tests is prohibitive.

It’s a terrible situation to be in. If you’ve lost a dog or cat to heart disease, you’re bound to be fearful it could happen again to another pet. You want to take proactive steps to help your current dearly loved dog or cat avoid the problem, but you can’t afford the tests that will tell you whether or not you need to do more to insure the health of your companion animal.
It feels as if you have no choice but to wait to see if heart disease sneaks up silently to claim another four-legged member of your family.

That is, until now.

At long last, veterinary medicine has developed a blood test that can identify which dogs and cats are at greatest risk for heart disease and heart failure.

The test is called a proBNP test. BNP = B-type Natriuretic Peptide.
The proBNP is a blood test that measures how much peptide hormone, released by the heart, is in circulation in your pet’s body. This hormone is only released when the heart is pushed beyond its capacity.

Very early in the disease process, small amounts of the hormone will be released into your dog’s or cat’s bloodstream, and it’s presence is a signal that steps must be taken in order to preserve your pet’s heart health.

If heart pathology continues to progress, the blood value of the peptide hormone will continue to rise.

Adopted with courtesy from the article by Dr. Becker: http://healthypets.mercola.com