<prompt> Single second hea sound is seen in -TOFhypeensionPulmonary oedemaMI  <response>: The four components of the tetralogy of Fallot are malaligned VSD,obstruction to RV outflow, aoic override of the VSD, and RVhyperophy due to the RVs response to aoic pressure thelarge VSD. Harrisons principle of internal medicine,20edition,pg no.1554 