Posts Tagged ‘TOF’

Second heart sound in TOF is often single and loud . It is often  best heard in left 2nd intercostal space as well as on right 2nd  space.

This is primarily due

  1. Presence of  pulmonary stenosis  and  resultant reduced pulmonary blood flow makes P2 soft or absent .Hence  A2 becomes loud by default.
  2. In tune with any  cono -truncal anomaly  , aortic root  is  anteriorly  malposed  in TOF. This brings the aorta  closer to chest wall  (Nullifying the  aquastic insulation  of main  pulmonary trunk  ) and results in a  booming aortic  second heart sound.
  3. Increased flow across  aortic valve . In cyanotic heart disease with reduced pulmonary blood flow aortic flow is augmented and may even result in dilatation of aorta . A large aorta with increased flow is perfect setting  for  generating a loud A2  . It  is common to hear a  aortic ejection click as well in these situations .

When you hear a single  second heart sound at  the base  of heart  , how do you recognise it to be   A2  or P2 ?

Will be answered shortly.

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Heart is the first organ to differentiate in the fetus.The first heart beat begins on the 22nd day of fetal life ! . From that day , it’s function is linearly determine the   fetal growth  .It continues in the new-born,  infancy and  up to late child hood.

It is no surprise  then, to detect growth retardation in congenital heart disease. A proper evaluation begins right from fetal mass / birth weight estimation  .Motor and cognitive milestones should be assessed meticulously .

The pattern of growth affliction is  complex  and poorly understood.Few  working rules are  often taught in cardiology classrooms.

Caution : This is a too simplified version. Discerned readers should consult all sources cited here.

Acyanotic heart disease

ASD, VSD, PDA  tend to affect weight gain  more but generally do not affect height  much  . But, the onset of pulmonary  hypertension early in the course will severely  affect height as well.

Co arctation of  Aorta and other Aortic interruptive   diseases  can have a differential  affection of growth . (Upper part of body > Lower part)

Cyanotic heart disease

CHD  affects both height and weight proportionately. Cyanotic  heart disease with increased pulmonary blood flow  the overall survival is less ,  recurrent failure is common  and hence growth and development is more affected.

The mechanism of stunted  growth.

The often used terminology  ‘failure to thrive” , may not be attributed to heart disease per-se. It has to be multi factorial and  is related to  social well-being  ,  feeding habits , and mother’s effort  , interruptions due to co existing illness , effects of surgery  etc. Obviously these factors operate  more  in infants with increased pulmonary blood flow.

Effect  on cognitive function

Contrary  to the expectations  even chronic hypoxia and cyanosis has no compelling effects  on the child’s intelligence . Unless there is co existing  neurological defects severe compromise of cognition  is  uncommon.

However now we realise , brain development do  suffer   in hypoxic environment.In fact, the damage  to cognition could start right from the fetus .

New evidence is coming  up.

*Recurrent hypoxia spells and convulsions in TOF  can lead to reduced cognition

Is the normal  growth  and development   restored after complete correction of the disease by  cardiac surgery ?

The expected benefit is usually achieved  . The catch up occurs . But it is not guaranteed,   especially in  cyanotic heart disease. As , many times the  destined growth of a child   is  reprogrammed and  predetermined  in the fetus itself.

Link to a rare review article on the topic

References  on Growth impairment in congenital heart disease


R. L. Naeye, “Anatomic features of growth failure in congenital heart disease,” Pediatrics, vol. 39, no. 3, pp. 433–440, 1967.

A. Mehrizi and A. Drash, “Birth weight of infants with cyanotic and acyanotic congenital malformations of the heart,” Journal of Pediatrics, vol. 59, no. 5, pp. 715–718, 1961.

R. J. Levy, A. Rosenthal, D. C. Fyler, and A. S. Nadas, “Birthweight of infants with congenital heart disease,” American Journal of Diseases of Children, vol. 132, no. 3, pp. 249–254, 1978.

H. H. Kramer, H. J. Trampisch, S. Rammos, and A. Giese, “Birth weight of children with congenital heart disease,” European Journal of Pediatrics, vol. 149, no. 11, pp. 752–757, 1990.

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Squatting is an excellent hemodynamic adaptation in patients with TOF. Children with TOF assume this posture   in  a natural and effortless manner . For years cardiologists are fascinated by this maneuver  and the mechanism by which it gives relief  to those patients with TOF.

Now , we have realised  this posture  has a new diagnostic role in echocardiography ! This paper was presented in the recently concluded  Annual scientific sessions of cardiological society of India held in Kolkatta December 2010

Download  the full   presentation in PDF  format  (  Squat Echo)

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Tetrology of Fallot is the commonest cyanotic heart disease . In 1973 , working at Portland,  Oregon , Bonchek  and colleagues created this classic with intense clinical acumen , that defined the way   how we understood TOF   in infancy  . Such studies  have  become extinct in this fast paced cardiology academia !

With due tributes , here is a slightly modified version of Bonchek classification of  TOF in infancy .

Every cardiologist must read every line of this article  which came 37 years ago  !

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