Lecture 17 9/23/24 Flashcards
What typically causes congenital heart disease?
cardiac anomalies and heart defects
What are the general characteristics of CHD?
-associated with the presence of a cardiac murmur
-most patients outwardly healthy at the time of detection
-findings of normal growth/lack of clinical signs at time of detection do not always imply good prognosis
What are the characteristics of CHD causes/predispositions?
-genetic transmission has been proven for a few defects
-distinct breed predispositions are recognized; likely that the common forms of canine CHD are heritable
What are the characteristics of cardiac murmurs as they relate to CHD?
-“innocent” murmurs are common in puppies and kittens in the absence of disease/abnormality
-innocent murmurs are always soft and systolic and become inaudible with time
-loud, diastolic, or continuous murmur always indicates presence of disease
What are the potential therapeutic approaches to congenital heart disease?
-surgical approaches +/- cardiopulmonary bypass
-interventional catheterization techniques
-medical therapy
What is the most appropriate treatment for CHD?
mechanical means
What are the characteristics of PDA?
-during fetal life, arterial duct provides a communication between aorta and pulmonary artery
-failure to close results in patent arterial duct
What is the pathophysiology of PDA?
-if the PDA is the only defect and pulmonary vascular resistance drops, the shunt is left-to-right
-left-to-right PDA imposes a volume load on the left atrium and left ventricle
What are the potential consequences of PDA?
-myocardial dysfunction
-mitral valve regurg.
-congestive heart failure
What causes increased pulmonary/venous return and left atrial/left ventricular enlargement in PDA?
eccentric hypertrophy
What is the signalment/history for PDA?
-small breed
-typically female
What are the physical findings consistent with PDA?
-continuous murmur
-bounding arterial pulse
What are the radiographic findings associated with PDA?
-cardiomegaly due to LAE/LVE
-pulmonary hyper-perfusion
-dilation of aorta and main pulmonary artery
What are the echocardiographic findings associated with PDA?
-LAE/LVE
-mitral valve regurg.
-continuous disturbed flow within MPA
-ductus visible in imaging
What are the therapy options for PDA?
-ligation following left lateral thoracotomy
-transcatheter ductal occlusion
When is thoracotomy and ligation chosen over transcatheter ductal occlusion?
when the size/morphology of the duct is small or when the patient is small
What are the characteristics of pulmonic stenosis?
-most often due to dysplasia of the pulmonic valve (type 2/type B)
-can see “typical” (type 1/type A) PS, where there is fusion between the leaflets
-RV must generate abnormally high systolic pressures in order to maintain flow and pressure beyond the stenosis
What is the pathophysiology of pulmonic stenosis?
-pressure gradient develops across the obstruction
-pressure gradient is a clinically relevant measure of disease severity
-imposes a pressure load on right ventricle
What are potential consequences of pulmonic stenosis?
-right-sided CHF
-ascites
Which breeds typically present with pulmonic stenosis?
terriers and brachycephalic breeds
What is the main physical finding in dogs with pulmonic stenosis?
systolic murmur best heard over the left heart base
What pressure gradient finding is considered severe for pulmonic stenosis?
> 80 mmHg
What are the potential therapy options for pulmonic stenosis?
-interventional catheterization/pulmonary balloon valvuloplasty
-surgical methods including patch graft and definitive repair
What are the characteristics of balloon valvuloplasty as a treatment for pulmonic stenosis?
-relatively low mortality
-efficacy highly dependent on nature of the stenosis
-favorable effect on survival in dogs with a gradient exceeding 80 mmHg
What are the consequences of leaving pulmonary stenosis untreated?
can cause CHF or sudden unexpected death
