Canine Atrial Septal Defect is a medium-severity cardiac condition that can affect dogs of all ages and breeds. An atrial septal defect (ASD) is a congenital hole in the wall separating the heart's upper chambers. Blood shunts between atria, overloading the right side of the heart. Small defects may be clinically silent; large ones cause heart failure. It is documented across 4 breeds, though prevalence and severity can differ significantly between them. It typically becomes apparent at Birth. Early signs to watch for include heart murmur, exercise intolerance, right-sided heart enlargement, and arrhythmias. When treatment is required, costs are estimated at £3,000-£8,000 depending on severity, location, and the specific intervention needed. Canine Atrial Septal Defect has a hereditary component, so health-screening certificates from the breeder are strongly recommended for predisposed breeds. This page covers symptoms, treatment options, and preventive steps — along with breed-specific information where available.

Signs & Symptoms

The following symptoms are commonly associated with Canine Atrial Septal Defect in dogs. If your dog displays several of these signs, consult your vet promptly — early diagnosis typically leads to better outcomes.

• Heart murmur
• Exercise intolerance
• Right-sided heart enlargement
• Arrhythmias
• Signs of heart failure in severe cases

Treatment Overview

Small ASDs may require no treatment. Larger defects in dogs with clinical signs can be closed via minimally invasive catheter-based occlusion or open-heart surgery. Medical management of heart failure is used otherwise.

Typical onset: Birth

Prevention & Screening

While not all cases of Canine Atrial Septal Defect can be prevented, the following steps reduce risk or enable earlier intervention:

• Cardiac screening of breeding stock
• Avoid breeding affected dogs