The following statements are true of patent ductus aeriosus(PDA) except -

Ans. is 'a' i.e., i.e., Spontaneous closure occurs in some term infants Spontaneous closure of PDA 1) In premature infants In premature infants spontaneous closure of PDA may occur because in these infants PDA is due to unresponsiveness to oxygen and there is no structural abnormality. 2)In Full term infants Unlike that in premature infants, spontaneous closure of a PDA does not usually occur in full term infants. This is because the PDA in term infants results from a structural abnormality of the ductal smooth muscle. Clinical manifestations of PDA o Patient may be asymptomatic Symptoms develop early and CHF may develop at 6 to 8th weeks of age. o Common symptoms --> Dysnea on exeion, palpitation and frequent chest infections. Signs o Tachypnea & Tachycardia o Bounding pulse with wide pulse pressure (with elevated systolic and lower diastolic pressure). o Hyperkinetic cardiac impulse Systolic or continuous thrill. o Accentuated Si o Narrow or paradoxical split of S, (But it may be masked by continuous murmur since maximum intensity of continous murmur occurs at S,). Continous (machinery) murmur --> Murmur stas after Si and reaches the peak at S2. It then diminishes and is audible only during a pa of the diastole. Murmur is best heard at second left intercostal space and is also heard below left clavicle. S3 may occur at apex followed by a delayed diastolic murmur.