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  #1  
Old 08-31-2012
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Stethoscope Why Single S2 in TOF!

So here's the basic, S2 has two parts:
A2... P2 (In this order)
Now, With TOF we have VSD and Pulm stenosis....
How doe that lead to a single S2???
Esp when the child in the question stem is just 2months old (Can eissenmeger's occur this early??? )
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Old 08-31-2012
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Single S2 means only A2 component is audible and P2 is not audible because of severe Pulmonary infundibular stenosis (almost leading to pulmonary atresia) so very less blood (almost none) is flowing thorough the pulmonary artery, therefore no P2.
Moreover this may lead to no blood to Lungs for oxygenation ,but PDA and newly developed collaterals provide blood to lungs for oxygenation.
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Old 08-31-2012
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Quote:
Originally Posted by step_enhancer View Post
Single S2 means only A2 component is audible and P2 is not audible because of severe Pulmonary infundibular stenosis (almost leading to pulmonary atresia) so very less blood (almost none) is flowing thorough the pulmonary artery, therefore no P2.
Moreover this may lead to no blood to Lungs for oxygenation ,but PDA and newly developed collaterals provide blood to lungs for oxygenation.
The single S2 is because only the A2 component closes
Children with TOF have Sub-pulmonary Stenosis (that is the stenosis is below the valve not in the valve itself).
the degree of stenosis gives the prognosis

Pulmonary atresia is incompatible with life unless a ASD or VSD occurs at the same time.
Remember the 5 T's of cyanotic heart disease? well guess what, add pulmonary stenosis to that because it will also give cyanosis.
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Single S2;
  • When S2 remains single throughout the respiratory cycle, one component is absent or the two components are persistently synchronous.
  • The most common cause of a single S2 is inaudibility of the P2 in older adults with increased anteroposterior chest dimensions.
  • In the setting of congenital heart disease, a single S2 due to absence of the pulmonary component is a feature of pulmonary atresia, severe pulmonary valve stenosis, dysplastic pulmonary valve, or complete transposition of the great arteries.
  • Conversely, a single S2 due to inaudibility of the A2 occurs when the aortic valve is immobile (severe calcific aortic stenosis) or atretic (aortic atresia).
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Old 08-31-2012
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"The 2nd heart sound (S2) is often single because the pulmonary component is markedly reduced. A prominent right ventricular impulse and a systolic thrill may be present"

Source :http://www.merckmanuals.com/professi...of_fallot.html

Read under tet spells.

Quote:
Originally Posted by XpaezX View Post
The single S2 is because only the A2 component closes
Children with TOF have Sub-pulmonary Stenosis (that is the stenosis is below the valve not in the valve itself).
the degree of stenosis gives the prognosis

Pulmonary atresia is incompatible with life unless a ASD or VSD occurs at the same time.
Remember the 5 T's of cyanotic heart disease? well guess what, add pulmonary stenosis to that because it will also give cyanosis.
I know stenosis is below the valve ,but if the stenosis is too much ,very little blood will flow through the pulmonary valve leading to Inaudibility of pulmonary component .Right to left shunt develops.
Sometimes pulmonary infudibular stenosis is so much it leads to atresia ,then VSD,PDA and collaterals help the infant to remain alive .I am sure about this ,my dad is a senior cardiologist,i discussed with him.
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Old 09-01-2012
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Quote:
Originally Posted by step_enhancer View Post
"The 2nd heart sound (S2) is often single because the pulmonary component is markedly reduced. A prominent right ventricular impulse and a systolic thrill may be present"

Source :http://www.merckmanuals.com/professi...of_fallot.html

Read under tet spells.



I know stenosis is below the valve ,but if the stenosis is too much ,very little blood will flow through the pulmonary valve leading to Inaudibility of pulmonary component .Right to left shunt develops.
Sometimes pulmonary infudibular stenosis is so much it leads to atresia ,then VSD,PDA and collaterals help the infant to remain alive .I am sure about this ,my dad is a senior cardiologist,i discussed with him.
I didnt say you were wrong i just tried to be morE precise, relax dude
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Quote:
Originally Posted by XpaezX View Post
I didnt say you were wrong i just tried to be morE precise, relax dude
I thought u meant something else .Sorry if u felt I was being Rude ,I dint mean to .sorry for the misunderstanding.
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Old 09-05-2012
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I Saw Single S2 in Transposition of the great vessels in a Q stem???

can somebody explain how
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Quote:
Originally Posted by step_enhancer View Post
I Saw Single S2 in Transposition of the great vessels in a Q stem???

can somebody explain how
It is because that aorta is located in front of the pulmonary artery in TOGV. So, the A2 is better heard than the P2 (soft) which on auscultation is heard as a single S2.
Also, in order for infant to survive there must be a shunt between the right and left heart. In intra-uterine life it is via a patent forman ovale and PDA.
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Old 08-26-2013
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there is single S2 with:
  • severe pulmonary hypertension
  • single semilunar valves: Aortic atresia, Pulmonary atresia, Truncus arteriosus
  • d-TGA, l-TGA
  • sever Aortic stenosis
so this is seen in any condition that there is a very severe atrio-ventricular valve stenosis or atresia of on of them.
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