A 29–day old child presents with features of congestive cardiac failure and left ventricular hypertrophy. Auscultation shows a short systolic murmur. Most likely diagnosis is –
The answer is quite obvious.
TOF and TGA are cyanotic heart diseases and
Rheumatic fever can be ruled out on basis of age. (Age group of rheumatic fever is 5-15 yrs)

Clinical manifestation of VSD 

The patients become symptomatic around 6 to 10 weeks of age.
At this time CHF may develop.
Frequent symptoms → Palpitation, dysnea on exertion and chest infections.

Signs

Hyperkinetic precordium with a thrill at the left sternal border.
Pansystolic murmur at left sternal border.
S1 & S2 are masked by pan-systolic murmur maximum intensity of murmur is at 3rd, 4th or 5th left interspace.
S2 can be make out at the pulmonary area (upper left sternal border) where it is not masked by pan-systolic murmur → S2 is widely split with accentuation of P2
S3 may be audible at the apex.
A delayed diastolic murmur in mitral area.
Pulmonary systolic ejection murmur in pulmonary area.
Rheumatic fever
Tetralogy of Fallot
Transposition of great arteries
Ventricular septal defect