Page 130 - Small Animal Internal Medicine, 6th Edition

102 PART I Cardiovascular System Disorders

TABLE 5.1
VetBooks.ir Breed Predispositions for Congenital Heart Disease

DISEASE
BREED
Patent ductus arteriosus Maltese, Pomeranian, Shetland Sheepdog, English Springer Spaniel, Keeshond, Bichon
Frise, Toy and Miniature Poodles, Yorkshire Terrier, Collie, Cocker Spaniel, German
Shepherd Dog, Chihuahua, Kerry Blue Terrier, Labrador Retriever, Newfoundland, Welsh
Corgi; female > male
Subaortic stenosis Newfoundland, Golden Retriever, Rottweiler, Boxer, German Shepherd Dog, Great Dane,
German Short-Haired Pointer, Bouvier des Flandres, Samoyed (valvular aortic stenosis: Bull
Terrier)
Pulmonic stenosis English Bulldog (male > female), Mastiff, Samoyed, Miniature Schnauzer, West Highland
White Terrier, Cocker Spaniel, Beagle, Labrador Retriever, Basset Hound, Newfoundland,
Airedale Terrier, Boykin Spaniel, Chihuahua, Scottish Terrier, Boxer, Chow, Miniature
Pinscher, other terriers & spaniels
Ventricular septal defect English Bulldog, English Springer Spaniel, Keeshond, West Highland White Terrier; cats
Atrial septal defect Samoyed, Doberman Pinscher, Boxer
Tricuspid dysplasia Labrador Retriever, German Shepherd Dog, Boxer, Weimaraner, Great Dane, Old English
Sheepdog, Golden Retriever; other large breeds (male > female?); cats
Mitral dysplasia Bull Terrier, German Shepherd Dog, Great Dane, Golden Retriever, Newfoundland, Mastiff,
Dalmatian, Rottweiler (?); cats (male > female)
Tetralogy of Fallot Keeshond, English Bulldog
Persistent right aortic arch German Shepherd Dog, Great Dane, Irish Setter

FIG 5.2
Continuous femoral artery pressure recording during surgical ligation of a patent ductus
arteriosus in a Poodle. The wide pulse pressure (left side of trace) narrows as the ductus is
closed (right side of trace). Diastolic arterial pressure rises because blood runoff into the
pulmonary artery is curtailed. (Courtesy Dr. Dean Riedesel.)

Compensatory mechanisms that promote increased heart overload. Excess fluid retention, declining myocardial con-
rate and volume retention maintain adequate systemic blood tractility stemming from the chronic volume overload, and
flow. However, the LV is subjected to a great hemodynamic arrhythmias contribute to the development of left-sided con-
burden, especially when the ductus is large, because the gestive heart failure (CHF).
increased stroke volume is pumped into the relatively high In rare cases, excessive pulmonary blood flow from a large
pressure aorta. Left ventricular (LV) and mitral annulus dila- ductus causes pulmonary vascular changes, abnormally high
tion in turn cause mitral regurgitation and further volume resistance, and pulmonary hypertension (see p. 114). As