Difference between revisions of "Pulmonic Stenosis"

Revision as of 09:38, 15 March 2011

Introduction

This is cardiovascular disease that is common in dogs and rare in cats and large animals.Predisposed breeds of dog include the Miniature Schnauzer, Fox Terrier, Chihuahua, Miniature Pinscher, Labrador Retriever, Newfoundland, Mastiff, Samoyeds and Terrier Breeds.

The three possible areas for pulmonic stenosis to occur:

1. Subvalvular or subpulmonic (occurs below the valve)

2. Valvular (occurs at the valve)

3. Supravalvular (occurs above the valve)

Most cases of pulmonic stenosis are valvular, whilst supravalvular pulomic stenosis is rare. Stenosis of the pulmonary outflow tract is the result of dysplastic changes in the pulmonic valve. Concentric hypertrophy of the right ventricle forms as a direct result of the chronic pressure overload needed to surpass the increased resistance from the stenotic pulmonary outflow tract. This concentric hypertrophy causes decreased ventricular filling during diastole and elevated right atrial pressure from the blood are unable to fill the ventricle causes atrial dilation. Tricuspid valve regurgitation can also be present and adds to the atrial pressure.

Clinical Signs

Exercise intolerance, syncope and signs of right sided congestive heart failure (if severely affected). Sometimes the condition can be asymptomatic if only mildly affected.

Diagnosis

History and clinical signs can be indicative of heart disease. Upon physical examinaiton, it is likely that a systolic ejection murmur over pulmonary artery in the left heart base will be heard. There will usually be normal femoral pulses. There may be signs of right sided congestive heart failure, such as ascites and jugular distension & jugular pulses.

Radiographic findings may include right ventricular enlargement (DV view seen at 1 o'clock), right atrial enlargement and pulmonary artery enlargement (DV view seen at 2 o'clock). Changes are seen most clearly on the 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. Electrocardiographic (ECG) signs include right ventricular hypertrophy (deep S waves, right axis deviation).

Angiography may also be used to identify the defect.

Treatment

In mild to moderate cases, if there are no clinical signs then no treatment is needed. In severe cases an invasive procedure may need to be performed. Possible options for surgery include a balloon valvuloplasty (done if pulmonic leaflets are fused) or surgical repair (done when more complex lesions & obstructions are present): valvulotomy, pericardial patch graft.

Prognosis

Mild to moderate cases have a good prognosis. Severe cases have a guarded prognosis.

References

Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company
Ettinger, S.J, Feldman, E.C. (2005) Textbook of Veterinary Internal Medicine (6th edition, volume 2)W.B. Saunders Company
Fossum, T. W. et. al. (2007) Small Animal Surgery (Third Edition) Mosby Elsevier

@@ Line 1: / Line 1: @@
-*Common in dogs
+== Introduction<br> ==
-*Rare in cats
+This is cardiovascular disease that is common in dogs and rare in cats and large animals.Predisposed breeds of dog include the Miniature Schnauzer, Fox Terrier, Chihuahua, Miniature Pinscher, Labrador Retriever, Newfoundland, Mastiff, Samoyeds and Terrier Breeds.
-*Very rare in horses as an isolated abnormality; usually part of Tetralogy of Fallot
+The three possible areas for pulmonic stenosis to occur:
-===Signalment===
+. Subvalvular or subpulmonic (occurs below the valve)
-Genetics & Predisposed Breeds: Most common in smaller breeds (Miniature Schnauzer, Fox Terrier, Chihuahua, Miniature Pinscher); Larger breeds are also affected (Labrador Retriever, Newfoundland, Mastiff, Samoyeds); Terrier Breeds are frequently affected
+. Valvular (occurs at the valve)
-===Description===
+. Supravalvular (occurs above the valve)
-The three possible areas for pulmonic stenosis to occur:
+Most cases of pulmonic stenosis are valvular, whilst supravalvular pulomic stenosis is rare. Stenosis of the pulmonary outflow tract is the result of dysplastic changes in the pulmonic valve. Concentric hypertrophy of the right ventricle forms as a direct result of the chronic pressure overload needed to surpass the increased resistance from the stenotic pulmonary outflow tract. This concentric hypertrophy causes decreased ventricular filling during diastole and elevated right atrial pressure from the blood are unable to fill the ventricle causes atrial dilation. Tricuspid valve regurgitation can also be present and adds to the atrial pressure.&nbsp;
-. Subvalvular or subpulmonic (occurs below the valve)
+<br>
-. Valvular (occurs at the valve)
+== Clinical Signs<br>  ==
-. Supravalvular (occurs above the valve)
+Exercise intolerance, syncope and signs of right sided congestive heart failure (if severely affected). Sometimes the condition can be asymptomatic&nbsp; if only mildly affected.
+<br>
-*Stenosis of the pulmonary outflow tract is the result of dysplastic changes in the pulmonic valve
+== Diagnosis<br> ==
-*Most cases of pulmonic stenosis are valvular
+History and clinical signs can be indicative of heart disease. Upon physical examinaiton, it is likely that a systolic ejection murmur over pulmonary artery in the left heart base will be heard. There will usually be normal femoral pulses. There may be signs of right sided congestive heart failure, such as ascites and jugular distension &amp; jugular pulses.
-*Supravalvular pulmonic stenosis is rare
+Radiographic findings may include right ventricular enlargement (DV view seen at 1 o'clock), right atrial enlargement and pulmonary artery enlargement (DV view seen at 2 o'clock). Changes are seen most clearly on the dorsoventral view.
-*Concentric hypertrophy of the right ventricle forms as a direct result of the chronic pressure overload needed to surpass the increased resistance from the stenotic pulmonary outflow tract
+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.&nbsp;Electrocardiographic (ECG) signs include right ventricular hypertrophy (deep S waves, right axis deviation). <br>
-*Concentric hypertrophy causes decreased ventricular filling during diastole
+Angiography may also be used to identify the defect.<br>
-*Elevated right atrial pressure from the blood unable to fill the ventricle causes atrial dilation
+<br>
-*Tricuspid valve regurgitation can also be present and adds to the atrial pressure
+== Treatment<br> ==
-*In addition to the diagnostic methods listed below, angiography may be used to show the defect
+In mild to moderate cases, if there are no clinical signs then no treatment is needed. In severe cases an invasive procedure may need to be performed. Possible options for surgery include a balloon valvuloplasty (done if pulmonic leaflets are fused) or surgical repair (done when more complex lesions &amp; obstructions are present): valvulotomy, pericardial patch graft.
+<br>
-===Diagnosis===
+== Prognosis ==
-====History & Clinical Signs====
+Mild to moderate cases have a good prognosis. Severe cases have a guarded prognosis.
--Exercise Intolerance
+<br>
--Syncope
+== References<br> ==
--Signs of right sided congestive heart failure (severely affected)
+Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company<br>Ettinger, S.J, Feldman, E.C. (2005) Textbook of Veterinary Internal Medicine (6th edition, volume 2)W.B. Saunders Company<br>Fossum, T. W. et. al. (2007) Small Animal Surgery (Third Edition) Mosby Elsevier <br>
--Asymptomatic (mildly affected)
+<br>
-====Physical Exam====
+<br>
--Systolic ejection murmur over pulmonary artery in the left heart base
+[[Category:Cardiovascular_System_-_Developmental_Pathology]] [[Category:To_Do_-_Review]] [[Category:Cardiac_Diseases_-_Cat]] [[Category:Cardiac_Diseases_-_Dog]] [[Category:Cardiac_Diseases_-_Horse]]
--Usually normal femoral pulses
--Signs of right sided congestive heart failure may be present:
-*ascites
-*jugular distension & jugular pulses
-====Radiographic Findings====
--Right ventricular enlargement (DV view seen at 1 o'clock)
--Right atrial enlargement
--Pulmonary artery enlargement (DV view seen at 2 o'clock)
-(Changes are seen the most clearly on a dorsoventral view)
-====Echocardiographic Findings====
--Right ventricular hypertrophy
--Poststenotic dilation of the pulmonary artery
--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
-====Electrocardiographic (ECG)====
--Right ventricular hypertrophy (deep S waves, right axis deviation)
-===Treatment===
-Mild/Moderate Cases
--If there are no signs, no treatment is needed
-Severe Cases
--Animals that exhibit many of the clinical signs will need further treatment
-*Balloon valvuloplasty (done if pulmonic leaflets are fused)
-*Surgical repair (done when more complex lesions & obstructions are present): valvulotomy, pericardial patch graft
-===Prognosis===
-Mild/Moderate Cases
--Good prognosis
-Severe Cases
--Guarded prognosis
-==From Pathology==
-Obstructs blood flowing form the right ventricle to the pulmonary artery.  As with aortic stenosis may be subvalvular, valvular or supravalvular.  Valvular stenosis is the most common form in the dog.
-''Incidence:''
-*Increased incidence in English bulldogs, Cocker spaniels, Chihuahuas.
-*Autosomal dominant in Beagles.
-''Clinical Signs:''
-*Asymptomatic if mild or moderate.
-*If severe; exercise intolerance, stunting, syncope, right sided heart failure E.g. ascites.
-*Harsh systolic murmur at left heart base.
-*May hear splitting of the second heart sound due to delayed closure of the pulmonic valve.
-*Femoral pulse quality good but jugulars distended.
-''Diagnosis:''
-*Right ventricular enlargement on radiology, along with post-stenotic dilatation of the pulmonary artery and pulmonary undercirculation.
-*Abnormal valve can be imaged using echocardiography.
-*Severity of stenosis can be assessed using Doppler to calculate flow rates.
-''Treatment:''
-*Balloon valvuloplasty is treatment of choice.
-[[Category:Cardiovascular_System_-_Developmental_Pathology]]
-[[Category:To_Do_-_Cardiovascular]][[Category:Cardiac Diseases - Cat]]
-[[Category:Cardiac Diseases - Dog]][[Category:Cardiac Diseases - Horse]]