Congenital Cardiac Diseases in Dogs and Cats Part 8

A set of vocabulary terms and definitions covering the pathophysiology, clinical signs, and treatments of congenital cardiac diseases in dogs and cats as described in the lecture.

Aortic stenosis (AS)

A condition characterized by narrowing due to fibrotic tissue at, above, or below the aortic valve, which impedes left ventricular emptying and leads to concentric hypertrophy.

Subvalvular AS (SAS)

The most common form of aortic stenosis in dogs, involving a lesion located below the aortic valve.

Patent ductus arteriosus (PDA)

The failure of the fetal ductus arteriosus to close after birth, allowing blood to shunt from the descending aorta to the main pulmonary artery.

Pulmonic stenosis (PS)

Constriction of the right ventricular (RV) outflow tract (RVOT) due to narrowing of the pulmonary valve or the area adjacent to it.

Ventricular septal defect (VSD)

Failure of the intraventricular septum to fully develop, which most commonly results in blood shunting from the left side of the heart to the right.

Innocent murmurs

Low-grade systolic murmurs in dogs under six months of age that do not represent underlying cardiac disease.

Continuous / Machinery-like murmur

A classic auscultation finding loudest over the left heart base, diagnostic for patent ductus arteriosus (PDA).

Reverse PDA

A rare condition where a large PDA creates pulmonary hypertension, reversing blood flow (right-to-left) and causing unoxygenated blood to enter the descending aorta.

Polycythemia vera

An elevated hematocrit level resulting from chronic hypoxia, often seen in right-to-left shunting defects like reverse PDA or large VSDs.

Balloon valvoplasty

A non-invasive procedure via cardiac catheterization used to reduce the pressure gradient in cases of pulmonic stenosis or occasionally aortic stenosis.

Atenolol / Sotalol

Beta-blockers used in the medical management of severe aortic stenosis or pulmonic stenosis to reduce the risk of arrhythmias.

High-risk SAS Pressure Gradient

An aortic pressure difference measured over $80\,mmHg$, which indicates a high risk of sudden death within three years.

Caudal hypoxia

A clinical sign of right-to-left shunting (reverse PDA) where only the rear half of the body receives poorly oxygenated blood.

Pulmonary artery banding

A palliative surgical procedure for VSD that decreases RV outflow tract resistance and decreases left-to-right shunting.

Tetralogy of Fallot

A complex congenital defect consisting of four abnormalities, including pulmonic stenosis, for which bulldogs are over-represented.

Concentric hypertrophy

Thickening of the ventricular walls resulting from pressure overload, typically seen in the left ventricle with AS and the right ventricle with PS.