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Ventricular Septal Defect (view source)
Revision as of 13:30, 5 September 2008
, 13:30, 5 September 2008New page: {{toplink |backcolour = |linkpage =Cardiology - WikiClinical |linktext =Cardiology |sublink1=Cardiovascular Conditions - WikiClinical |subtext1=CARDIOVASCULAR CONDITIONS |maplink1= Cardiov...
{{toplink
|backcolour =
|linkpage =Cardiology - WikiClinical
|linktext =Cardiology
|sublink1=Cardiovascular Conditions - WikiClinical
|subtext1=CARDIOVASCULAR CONDITIONS
|maplink1= Cardiovascular Conditions (Content Map) - WikiClinical
|pagetype=Clinical
}}
<br>
[[Image:VSD1.jpg|right|thumb|125px|<small><center>'''Ventricular septal defect'''. Courtesy of A. Jefferies</center></small>]]
[[Image:VSD2.jpg|right|thumb|125px|<small><center>'''Ventricular septal defect'''. Courtesy of A. Jefferies</center></small>]]
*Most common congenital cardiac abnormality in large animals
*Second most common congenital cardiac abnormality in cat
*Occurs in dogs
===Signalment===
Genetics & Predisposed Breeds: Keeshonds, English Springer Spaniel, English Bulldog, West Highland White Terrier
===Description===
*Ventricular defects are usually in the membranous area of the interventricular septum.
*On the right ventricle, the septal defect usually occurs below the septal leaflet of the tricuspid valve.
*On the left ventricle, the septal defect usually occurs under the aortic valve.
*Ventricular Septal Defects can occur alone or in combination with other congenital malformations.
*Usually blood flows from the higher pressure left ventricle through the shunt to the lower pressure right ventricle. Left to right shunting causes volume overload of the pulmonary circulation and consequently the left atrium and ventricle. The consequences of L-R shunting are left sided congestive heart failure and pulmonary hypertension.
*Shunting can be reversed from L-R towards R-L if pulmonary hypertension increases the pressure on the right side of the heart and/or there is also pulmonic stenosis (Eisenmengers's Physiology). A R-L shunt would allow unoxygenated blood into the systemic circulation resulting in arterial hypoxemia. Increased amounts of blood into the systemic circulation causes an increased right sided pressure load.
===Diagnosis===
====History & Clinical Signs====
-Coughing
-Exercise Intolerance
-Left-sided congestive heart failure
-Right-sided heart failure
-Cyanosis (with R-L shunt)
-Asymptomatic (small defects)
====Physical Exam====
-Holosystolic murmur over left apex and right sternal boarder
-Systolic murmur over pulmonic valve (pulmonic stenosis)
-Diastolic murmur over aortic valve (aortic regurgitation)
-Murmur from mitral regurgitation (caused by left ventricular dilation)
====Radiographic Findings====
Normal findings with small defects
'''Left to Right Ventricular Septal Defect'''
-Pulmonary overcirculation
-Left-sided heart enlargement
-Signs of left-sided heart failure
-Enlargement of pulmonary artery (if pulmonic stenosis is present)
-Right ventricular enlargement (seen with pulmonary hypertension)
'''Right to Left Ventricular Septal Defect'''
-Right-sided heart enlargement
-Normal to enlarged pulmonary artery
====Echocardiographic Findings====
-Visible defect in the intraventricular septum
Doppler confirms blood shunting through defect
====Electrocardiographic (ECG)====
-Left sided enlargement (L-R shunt)
-Right ventricular hypertrophy (R-L shunt)
-Arrhythmias
-Wide or notched Q wave showing abnormal septal depolarization
===Treatment===
'''Mild/Moderate Cases'''
-No treatment
-May close on their own
'''Severe Cases'''
Medications:
-Drugs to decrease volume through the shunt (arterial vasodilators for R-L shunt)
-Drugs to combat heart failure
Surgery:
-Surgical closure of the septal defect (open heart surgery rarely performed in veterinary patients)
-Pulmonary artery banding (Palliative surgical procedure to decrease left to right shunting)
*Use of vasodilators and the surgical procedures above are contraindicated with a right to left shunt
===Prognosis===
'''Mild/Moderate Cases'''
-Excellent
'''Severe Cases'''
-Guarded (L-R shunts)
-Poor (R-L shunts)
|backcolour =
|linkpage =Cardiology - WikiClinical
|linktext =Cardiology
|sublink1=Cardiovascular Conditions - WikiClinical
|subtext1=CARDIOVASCULAR CONDITIONS
|maplink1= Cardiovascular Conditions (Content Map) - WikiClinical
|pagetype=Clinical
}}
<br>
[[Image:VSD1.jpg|right|thumb|125px|<small><center>'''Ventricular septal defect'''. Courtesy of A. Jefferies</center></small>]]
[[Image:VSD2.jpg|right|thumb|125px|<small><center>'''Ventricular septal defect'''. Courtesy of A. Jefferies</center></small>]]
*Most common congenital cardiac abnormality in large animals
*Second most common congenital cardiac abnormality in cat
*Occurs in dogs
===Signalment===
Genetics & Predisposed Breeds: Keeshonds, English Springer Spaniel, English Bulldog, West Highland White Terrier
===Description===
*Ventricular defects are usually in the membranous area of the interventricular septum.
*On the right ventricle, the septal defect usually occurs below the septal leaflet of the tricuspid valve.
*On the left ventricle, the septal defect usually occurs under the aortic valve.
*Ventricular Septal Defects can occur alone or in combination with other congenital malformations.
*Usually blood flows from the higher pressure left ventricle through the shunt to the lower pressure right ventricle. Left to right shunting causes volume overload of the pulmonary circulation and consequently the left atrium and ventricle. The consequences of L-R shunting are left sided congestive heart failure and pulmonary hypertension.
*Shunting can be reversed from L-R towards R-L if pulmonary hypertension increases the pressure on the right side of the heart and/or there is also pulmonic stenosis (Eisenmengers's Physiology). A R-L shunt would allow unoxygenated blood into the systemic circulation resulting in arterial hypoxemia. Increased amounts of blood into the systemic circulation causes an increased right sided pressure load.
===Diagnosis===
====History & Clinical Signs====
-Coughing
-Exercise Intolerance
-Left-sided congestive heart failure
-Right-sided heart failure
-Cyanosis (with R-L shunt)
-Asymptomatic (small defects)
====Physical Exam====
-Holosystolic murmur over left apex and right sternal boarder
-Systolic murmur over pulmonic valve (pulmonic stenosis)
-Diastolic murmur over aortic valve (aortic regurgitation)
-Murmur from mitral regurgitation (caused by left ventricular dilation)
====Radiographic Findings====
Normal findings with small defects
'''Left to Right Ventricular Septal Defect'''
-Pulmonary overcirculation
-Left-sided heart enlargement
-Signs of left-sided heart failure
-Enlargement of pulmonary artery (if pulmonic stenosis is present)
-Right ventricular enlargement (seen with pulmonary hypertension)
'''Right to Left Ventricular Septal Defect'''
-Right-sided heart enlargement
-Normal to enlarged pulmonary artery
====Echocardiographic Findings====
-Visible defect in the intraventricular septum
Doppler confirms blood shunting through defect
====Electrocardiographic (ECG)====
-Left sided enlargement (L-R shunt)
-Right ventricular hypertrophy (R-L shunt)
-Arrhythmias
-Wide or notched Q wave showing abnormal septal depolarization
===Treatment===
'''Mild/Moderate Cases'''
-No treatment
-May close on their own
'''Severe Cases'''
Medications:
-Drugs to decrease volume through the shunt (arterial vasodilators for R-L shunt)
-Drugs to combat heart failure
Surgery:
-Surgical closure of the septal defect (open heart surgery rarely performed in veterinary patients)
-Pulmonary artery banding (Palliative surgical procedure to decrease left to right shunting)
*Use of vasodilators and the surgical procedures above are contraindicated with a right to left shunt
===Prognosis===
'''Mild/Moderate Cases'''
-Excellent
'''Severe Cases'''
-Guarded (L-R shunts)
-Poor (R-L shunts)