KAHLER: Dog's faulty ticker needs further look

Brodie has been found to have a heart murmur, and his owner is understandably concerned. Fortunately, the murmur isn't causing problems yet.

A murmur is simply a sound created within the heart as a result of abnormal blood flow or turbulence. The cause of the turbulence must be determined, along with potential problems. Some heart murmurs are inconsequential, while others may indicate major problems.

The heart is a one-way pump consisting of four chambers: one pair, the left and right atria, on top of another pair, the left and right ventricles, separated from one another by one-way "flapper" valves.

Blood flows through the heart in one direction as the chambers contract in rhythm, pushing the valve flaps open to allow the blood to flow from each atrium into each ventricle. Then, the ventricles contract, closing the valves back to each atrium and opening the valves to allow blood to flow from each ventricle.

The right ventricle pumps blood to and through the lungs and back to the heart into the left atrium. From the left atrium the blood flows through the mitral valve into the left ventricle, then from there through the aortic valve and out to the body, returning into the right atrium through the tricuspid valve into the right ventricle to restart the trip.

Brodie probably has a mitral murmur, the most common type in dogs, meaning there is turbulence in the blood flow through his mitral valve, the one between his right atrium and his right ventricle. We grade heart murmurs on a scale from one to six, six being the loudest. We were not given a number designation for Brodie's murmur. Generally speaking, the louder the mitral murmur, the greater the potential for problems.

I recommend Brodie have his heart evaluated. This should involve a few different studies, including a chest radiograph, an electrocardiogram (ECG), blood pressure determination and an echocardiogram (ultrasound of the heart). Using these studies, we can try to determine what is causing Brodie's murmur and then decide whether there is disease associated with it. A mitral murmur usually results from a mitral valve that does not seal properly when it shuts, allowing blood to flow back into the left atrium instead of forward out of the left ventricle to the body. This back flow causes an audible turbulence. If significant enough in volume, a murmur can lead to congestive heart failure.

Jeff Kahler is a veterinarian in Modesto. Questions can be submitted to Your Pet in care of LifeStyles, The Modesto Bee, P.O. Box 5256, Modesto 95352.