Exam 4 - Congenital Heart Disease Flashcards
what is a PDA?
very common congenital heart disease with a persistent communication between the aorta & pulmonary arteries
why does a PDA cause a continuous murmur heard best at the left base of the heart in the axillary region?
the abnormality is a tube - nothing stops it!
why does PDA cause bounding pulses?
big discrepancy between the systolic & diastolic pressures - felt well on the femoral artery
what pathology does PDA cause to the heart? why?
eccentric hypertrophy - volume overload to different parts of the cardiovascular system
what are the characteristics of a PDA?
- continuous murmur - heard best at the left base
- bounding pulses
- volume overload
- left heart enlargement
T/F: PDA & sub-aortic stenosis are both common congenital abnormalities of the heart
true
why does sub-aortic stenosis cause a pressure overload?
the ventricle is consistently having to generate high pressures to get across the stenotic part of the aorta causing a concentric hypertrophy of the left ventricle
why do you hear a systolic murmur associated with pulmonic stenosis?
obstruction of flow during systole - flow is accelerated causing a murmur
why do you see right ventricular concentric hypertrophy in pulmonic stenosis?
pressure overload - right ventricle is consistently having to generate high pressures to get past the stenotic aspect of the pulmonary artery causing a concentric hypertrophy of the right ventricle
what are 2 less common congenital abnormalities that cause abnormal communication?
atrial septal defect & ventricular septal defect
with the atria both being low pressure, of left & right, which is higher?
typically left - why you see a left to right shunt
why do you not hear a murmur with atrial septal defects?
you have blood flowing from a slightly higher pressure chamber to a slightly lower pressure chamber - not a huge difference between pressures
why do you hear a murmur associated with ventricular septal defects?
the ventricles have a much larger difference in chamber pressure! so, the higher difference causes turbulent flow, resulting in a murmur
T/F: a loud murmur in a VSD, means you have a small defect which is a better prognosis
true - the larger the hole, the quieter the murmur
why don’t you typically see right-sided cardiac enlargement in VSD? why do you see left-sided heart enlargement instead?
the defect between the left & right ventricle is located just below the pulmonic valve, so the blood immediately goes back through the lungs & into the left side of the heart causing left-sided signs
what is tetralogy of fallot?
VSD, pulmonic stenosis, right ventricular concentric hypertrophy, & overriding aorta that receives blood from both ventricles
what signs are associated with ASD?
- no murmur or soft left base systolic murmur
- left to right shunt, can reverse
- right heart enlargement
what are the characteristics associated with VSD?
- right sternal systolic murmur
- left to right shunt, can reverse
- left heart enlargement, or both
what are the characteristics of pulmonic stenosis?
- systolic murmur left base
- normal pulses
- increased pressure load
- right heart enlargement
what are the characteristics associated with sub-aortic stenosis?
- systolic murmur left base
- normal to reduced pulses
- increased pressure load
- left heart enlargement
what is pulmonic stenosis?
common congenital abnormality that usually has valve dysplasia & stenosis of the pulmonary artery which is obstructive to flow - causes an increased pressure load to the right side of the heart
what is the most common congenital cardiac abnormalities in cats?
- valve dysplasia
- septal defects
- PDA - can be ligated!!
what should you do if you have a kitten with a murmur, heart failure, & cyanosis?
do an echo & consider referring to a cardiologist
what is the typical clinical presentation of congenital heart disease that is causing pathology?
heart failure & cyanosis - varying degrees of severity, can see congenital disease in an older animal
what are the risks associated with a congenital heart disease going undiagnosed & left untreated?
- developing symptoms
- heart failure
- arrhythmias/sudden death - particularly with sub-aortic stenosis
- endocarditis with SAS & VSD
- change in shunt direction (goes to right to left)
- cyanosis: right to left shunt or shunt reversal
what are the 7 guiding questions that should be used when assessing a patient for congenital heart disease?
- is there a murmur that suggests the presence of congenital heart disease?
- do the murmur characteristics (location/timing), & pulse quality provide insight into the most likely CHD?
- does the signalment provide information for identifying the most likely CHD?
- is there a known history of CHD in a littermate, sire, dam, or relative?
- do the current clinical signs suggest the presence of CHD?
- do the clinical signs require stabilization of the patient prior to referral to a specialist
- what are the next steps for imaging: thoracic rads, echo, CT angiography
what is the murmur location, timing, & pulse quality of a PDA?
left base (cranial, axillary), continuous murmur, & bounding pulses
what is the murmur location, timing, & pulse quality of SAS?
left base, systolic murmur, & decreased pulse quality
what is the murmur location, timing, & pulse quality of PS?
left base, systolic murmur, & normal pulse quality
what are innocent & functional non-pathological murmurs?
innocent - no structural abnormality
functional - physiologic cause, increased flow velocity in great vessels
what are the characteristics associated with non-pathological innocent/physiologic murmurs?
- grade 1-2/6 (soft murmur)
- left basilar
- disappear by approximately 4ish months of age
is a grade 5/6 systolic murmur in a puppy innocent?
never
does a puppy with a soft murmur & clinical signs of heart disease have an innocent murmur?
nope
what are some signs associated with left-sided heart failure seen upon physical exam?
increased lung sounds & tachypnea
what are some signs associated with right-sided heart failure seen upon physical exam?
ascites, jugular venous distension
why should you do thoracic radiographs in a patient with suspected congenital heart disease?
assess heart size & presence of L CHF - limited in ability to diagnose specific congenital abnormality
why should you do an echo in a patient with suspected congenital heart disease?
characterize the presence of concurrent congenital/acquired heart disease, CHD anatomy, direction of shunt flow, severity of stenosis, secondary chamber enlargement, & acquire measurements for procedural planning
where do you listen on your patients for the presence of a congenital cardiac abnormality causing a murmur? what valve are you listening to on the right side?
3 ICS, 4 ICS, 5 ICS
tricuspid valve
what are the limitations of using an echo for diagnosing congenital cardiac disease?
cost, operator skill level, & intent (diagnosis or procedural planning)
what are thoracic rads good for assessing congenital cardiac disease?
global heart size, chamber enlargement
evaluate pulmonary vasculature & pattern
at risk of CHF
managing CHF
if you see concentric hypertrophy of the left ventricle on echo, what congenital abnormality do you suspect?
sub-aortic stenosis
if you see concentric hypertrophy of the right ventricle on echo, what congenital abnormalities do you suspect?
pulmonic stenosis or tetralogy of fallot
if you see eccentric hypertrophy of the left ventricle/left atrium on echo, what congenital abnormalities do you suspect?
VSD or PDA
if you see eccentric hypertrophy of the right ventricle/right atrium on echo, what congenital abnormalities do you suspect?
tricuspid valve dysplasia or VSD
what congenital defects are associated with causing pressure overload in the heart?
- pulmonic stenosis
- sub-aortic stenosis
- tetralogy of fallot
what congenital defects are associated with causing volume overload in the heart?
PDA, ASD/VSD, or tricuspid/mitral valve dysplasia
what are thoracic rads used for in a patient with PDA?
- assess heart size
- pulmonary vasculature
- evidence of overcirculation
- presence of pulmonary edema
what is echo used for in a patient with PDA?
- assess heart size
- confirm PDA
- ductal morphology & size
- confirm shunt direction, left to right
- mitral regurgitation
- rule out other congenital defects
what are thoracic rads used for in a patient with pulmonic stenosis?
assess heart size
what is echo used for in a patient with pulmonic stenosis?
- assess heart size
- confirm PS & determine severity
- rule out annular hypoplasia
- rule out coronary anomalies
- rule out other congenital defects
what are thoracic rads used for in a patient with sub-aortic stenosis?
assess heart size & evaluate for pulmonary edema
what is echo used for in a patient with sub-aortic stenosis?
assess heart size, confirm SAS, determine severity, rule out endocarditis, & rule out other congenital defects
what is echo used for in a patient with VSD?
assess heart size, confirm VSD, determine shunt size & direction, rule out endocarditis, & rule out other congenital defects
what are some examples of interventional procedural treatment for congenital cardiac disease?
PDA occlusion, balloon valvuloplasty for valve stenosis or stenotic membranes
what are some examples of surgical procedural treatment for congenital cardiac disease?
PDA ligation & PA banding
what are some examples of surgical, with cardiopulmonary support, procedural treatment for congenital cardiac disease?
valve repair
what are some examples of hybrid procedural treatment for congenital cardiac disease?
VSD occlusion through the right ventricle
what are the most common congenital cardiac defects in the dog?
PDA, SAS, PS
what congenital cardiac abnormality causes volume overload with eccentric hypertrophy?
PDA - eccentric hypertrophy of the left heart
what congenital cardiac abnormalities causes pressure overload with concentric hypertrophy?
SAS & PS
what diagnostic is needed to make a definitive diagnosis for congenital cardiac disease?
echocardiogram
what congenital cardiac defect is associated with this rad?
sub-aortic stenosis
what congenital cardiac defect is associated with this rad?
pulmonic stenosis
what congenital cardiac defect is associated with this rad?
PDA
what is congenital heart disease?
defect of the heart or great vessels present at birth
