<prompt> First hea sound is soft in all, except:Sho PR intervalVentricular septal defectMitral regurgitationCalcified valve  <response>: Answer is A Sho PR interval Sho PR interval is associated with a Loud S,. SI is produced as a result of closure of AV valves. In sho PR interval mitral leaflets are at a greater distance from neutral as decreased interval between atrial contraction and ventricular systole does not allow them to return towards neutral before the ventricular contraction 