21 Mar Congenital Heart Disease in Dogs: An Overview
Congenital heart disease (CHD) refers to structural abnormalities of the heart or major blood vessels that develop before birth. Some defects cause no clinical signs, while others can lead to heart failure, exercise intolerance, or sudden cardiac events. So, without further ado, here is what you should know about congenital heart disease in dogs.
How Congenital Heart Disease Affects Dogs
These defects may:
- Alter normal blood flow
- Increase heart workload
- Causes abnormal heart rhythms
- Lead to congestive heart failure
Common Congenital Heart Defects
Defects Affecting Blood Flow Between Chambers
- Atrial Septal Defect (ASD) – A hole between the atria, leading to abnormal blood flow and right-sided heart enlargement.
- Ventricular Septal Defect (VSD) – A hole between the ventricles that can lead to congestive heart failure.
- Tetralogy of Fallot (TOF) – A complex defect involving pulmonic stenosis, a ventricular septal defect, an overriding aorta, and right ventricular hypertrophy. Causes cyanosis (blue gums) and severe exercise intolerance.
Defects Affecting Blood Vessel Development
- Patent Ductus Arteriosus (PDA) – A fetal blood vessel (ductus arteriosus) remains open, causing abnormal blood flow between the aorta and pulmonary artery.
- Truncus Arteriosus / Pseudotruncus Arteriosus – The aorta and pulmonary artery fail to separate, resulting in mixed oxygenated and deoxygenated blood flow.
Valve Abnormalities
- Pulmonic Stenosis (PS) – Narrowing of the pulmonary valve, restricting blood flow to the lungs.
- Subaortic Stenosis (SAS) – Narrowing below the aortic valve, forcing the heart to work harder.
- Mitral or Tricuspid Valve Dysplasia – Malformations of the heart valves, leading to leakage (regurgitation), heart enlargement, and eventual heart failure.
Obstructive or Structural Defects
- Cor Triatriatum Dexter (CTD) – A fibrous membrane divides the right atrium, restricting blood flow to the right ventricle. It may cause right-sided heart failure and ascites.
- Double Chambered Right Ventricle (DCRV) – A muscular obstruction divides the right ventricle into two chambers, increasing pressure.
- Double Outlet Right Ventricle (DORV) – Both the aorta and pulmonary artery originate from the right ventricle, disrupting normal circulation.
Breeds at Higher Risk
Some breeds are predisposed to congenital heart defects, including:
- Patent Ductus Arteriosus (PDA) – Miniature Poodles, Chihuahuas, Maltese
- Pulmonic Stenosis (PS) – Bulldogs, Terriers, Beagles
- Subaortic Stenosis (SAS) – Golden Retrievers, Newfoundlands, Rottweilers
- Ventricular Septal Defect (VSD) – English Bulldogs, Springer Spaniels
- Atrial Septal Defect (ASD) – Boxers, Standard Poodles
- Tetralogy of Fallot (TOF) – Keeshonds, Bulldogs
- Tricuspid Valve Dysplasia – Labrador Retrievers
- Mitral Valve Dysplasia – Bull Terriers
Diagnosis and Treatment
Diagnosis → Most congenital heart defects are first detected by a heart murmur in puppies. Echocardiography (ultrasound of the heart) is the gold standard for confirming a diagnosis.
Treatment → Some mild defects require no intervention, while others benefit from:
- Medical management (medications to control symptoms)
- Minimally invasive procedures (e.g., balloon valvuloplasty for PS, PDA occlusion)
- Surgery (reserved for select cases)
Why Early Detection Matters
Congenital heart defects can often be treated or managed effectively if diagnosed early. Routine puppy heart screenings, especially in at-risk breeds, can help detect issues before symptoms appear, leading to better outcomes. Contact us at Animal Cardiology Specialists of Nevada to schedule an appointment for your companion today.
Images used under creative commons license – commercial use (03/21/2025) Photo by Gabriel Martin on Unsplash