4,503
edits
Changes
Jump to navigation
Jump to search
no edit summary
Pulmonic stenosis (PS) is one of the three most common congenital cardiac defects in dogs. It is much less common in cats, and is usually recognised in association with other congenital cardiac defects in this species.
Pulmonic stenosis (PS) is one of the three most common congenital cardiac defects in dogs. It is much less common in cats, and is usually recognised in association with other congenital cardiac defects in this species.
Pulmonic stenosis may be '''subvalvular/infundibular''' (occurs below the valve), '''valvular''' (occurs at the valve) or'''Supravalvular''' (occurs above the valve).'''Most '''cases of PS in the dog are '''valvular''', whilst supravalvular PS is rare.
Pulmonic stenosis may be '''subvalvular/infundibular''' (occurs below the valve), '''valvular''' (occurs at the valve) or '''Supravalvular''' (occurs above the valve). '''Most '''cases of PS in the dog are '''valvular''', whilst supravalvular PS is rare.
'''Subvalvular (infundibular)''' PS is defined as a fibrous or fibromuscular diaphragm below the pulmonic valve or at the os infundibulum, or a more diffuse and extensive area of fibromuscular hypertrophy creating more of a tunnel or hour-glass deformity of the infundibulum.
'''Subvalvular (infundibular)''' PS is defined as a fibrous or fibromuscular diaphragm below the pulmonic valve or at the os infundibulum, or a more diffuse and extensive area of fibromuscular hypertrophy creating more of a tunnel or hour-glass deformity of the infundibulum.
Concentric hypertrophy of the right ventricle develops as a consequence of the chronic pressure overload resulting from obstruction to right ventricular outflow. Right ventricular hypertrophy may cause an infundibular narrowing of the right ventricular outflow tract (RVOT), exacerbating the stenosis and resulting in a dynamic component to the obstruction. A further consequence of right ventricular hypertrophy is reduced right ventricular diastolic filling and therefore elevated right atrial pressures with resultant right atrial dilation.
Concentric hypertrophy of the right ventricle develops as a consequence of the chronic pressure overload resulting from obstruction to right ventricular outflow. Right ventricular hypertrophy may cause an infundibular narrowing of the right ventricular outflow tract (RVOT), exacerbating the stenosis and resulting in a dynamic component to the obstruction. A further consequence of right ventricular hypertrophy is reduced right ventricular diastolic filling and therefore elevated right atrial pressures with resultant right atrial dilation.
In '''Bulldogs''', PS may be complicated by '''coronary artery anomalies'''.
==Signalment==
==Signalment==
Predisposed breeds of dog include the Miniature Schnauzer, Fox Terrier, Chihuahua, Miniature Pinscher, Labrador Retriever, Newfoundland, Mastiff, Samoyeds and Terrier Breeds.
Predisposed breeds of dog include the Miniature Schnauzer, Cocker Spaniel, Fox Terrier, Chihuahua, Miniature Pinscher, Labrador Retriever, Newfoundland, Mastiff, Boxer, Samoyed and English and French Bulldog.
== Clinical Signs ==
== History and Clinical Signs ==
A murmur is usually detected at the initial health check or primary vaccination.
Clinical signs include exercise intolerance, syncope and signs of [[Heart Failure, Right-Sided|right sided congestive heart failure]] (if severely affected). Animals may be asymptomatic.
== Diagnosis ==
== Diagnosis ==
===Physical Examination===
* Left-sided, systolic murmur with point of maximal intensity over the heart base
* Grade of murmur correlates with severity of stenosis for fixed obstructions
* Apex beat may be more palpable on the right hemithorax than the left if severe right ventricular hypertrophy is present.
There may be signs of [[Heart Failure, Right-Sided|right sided congestive heart failure]], such as ascites and jugular venous distension and hepatojugular reflux.
===Thoracic Radiographs===
Radiographic findings may include right ventricular enlargement (seen at 1 o'clock on a dorsoventral view), right atrial enlargement and pulmonary artery enlargement (seen at 2 o'clock on a dorsoventral view).
'''Echocardiographic''' findings may include right ventricular hypertrophy, poststenotic dilation of the pulmonary artery and abnormal pulmonic valve if the stenotic area is valvular. Doppler can be used to measure the pressure in the stenotic area and visualize abnormal flow.
'''Echocardiographic''' findings may include right ventricular hypertrophy, poststenotic dilation of the pulmonary artery and abnormal pulmonic valve if the stenotic area is valvular. Doppler can be used to measure the pressure in the stenotic area and visualize abnormal flow.