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===Ventricular Septal Defect===
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===[[Ventricular Septal Defect]]===
[[Image:VSD1.jpg|right|thumb|200px|<small><center>'''Ventricular septal defect'''. Courtesy of A. Jefferies</center></small>]]
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Often associated with other conditions E.g. [[Heart and Great Vessels Development - Pathology#Tetralogy_of_Fallot|Tetralogy of Fallot]].
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Usually occur high in the membranous region of the interventricular septum.  Blood flows from left to right ventricle during systole resulting in right ventricular overload, increased central venous pressure and pulmonary overcirculation.<br>
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'''''Eisenmenger's Syndrome''''': chronic pulmonary overcirculation results in pulmonary hypertension and increased right-sided pressure.  This facilitates right to left shunting and reduced lung perfusion, leading on to cyanosis.
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''Incidence:''
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*Not common in dogs but increased incidence in WHWTs and Cocker Spaniels.
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*More common in cats and cattle.
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''Clinical Signs:''
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*Depend upon size of defect, may include; exercise intolerance, venous congestion etc.
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*Harsh holosystolic murmur.  Murmur grade correlates inversely with the defect size.
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''Diagnosis:''
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*Left and right ventricular hypertrophy, often generalised cardiomegaly on radiology and ECG.
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*Pulmonary overcirculation on radiology.
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*Left ventricle hyperkinetic on echocardiography and often the defect may be visualised.  Doppler echocardiography may be useful.
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[[Image:VSD2.jpg|right|thumb|200px|<small><center>'''Ventricular septal defect'''. Courtesy of A. Jefferies</center></small>]]
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*Mitral regurgitation is common due to a change in size of the left ventricle and consequent alterations to the Mitral valve.
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''Treatment:''
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*Small defects require no treatment.
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*'''Pulmonary Banding''' protects the pulmonary circulation by restricting its blood flow.
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*Symptomatic therapy for left heart failure E.g ACE inhibitors.
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*Prognosis variable with defect size.
      
===Patent Ductus Arteriosus===
 
===Patent Ductus Arteriosus===
Author, Donkey, Bureaucrats, Administrators
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