Atrial Septal Defect

Atrial Septal Defect (ASD) refers to a hole in the septum (the wall seperating the left and right chambers in the upper half (the atria) of the heart.

Septal Defect is yet another hereditary cardiac disease, prevelant amongst Boxers. This disease has a polygenic mode of inheritance, with variable expression.

The condition may be so mild that it produces no visible symptoms. A stethescope will, in most cases, reveal a "swishing" sound or a 'murmur'as blood flows through the septal hole from left to right. We are not sure if the diagram is correct in showing blood passing both ways through the hole in the septum. From what we have read the blood only leaks as per the blue arrow, or left to right.... but we aren't doctors...

In mild cases of Septal Defect, treatment may not be warranted, and the dog may enjoy a normal life-span. However, these dogs will often be more susceptible to respiratory tract infections. We aren't sure why this is the case. We guess it has something to do with the incresed blood flow to the lungs due to the leakage from the left atrium to the right- the right atrium being the chamber that pumps blood to the lungs.

Signs of a major, life-threatening, defect include: cardiac arrhythmia (abnormal heart-beats), difficulty or rapid breathing,tiring quickly when walking/ exercising,swelling and unfotunately, sudden death.

The reason for death is usually attributable to the increased work-load the leakage forces upon the right atrium. Eventually, that chamber simply breaks-down, or fails.

Atrial Septal Defect is treatable. There are a battery of medications available to assist the heart and support it.

Dogs suffering from ASD should be on a limited exercise program (a tough requirement for a Boxer) and low salt (sodium) diet.

Many dogs respond positively to such treatment.

Surgery is also an option. But both the costs and the risks involved in open heart surgery often preclude this treatment.

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