I am having a little trouble understanding how to code late effects. Can anyone put into simple terms how to code for late effects?

For instance, how would you code these?

1)Scoliosis due to infantile paralysis

2)intraocular foreign body, left eye, secondary to blast injury that occurred in 1983.

3) Congestive heart failure Status post cerebral vascular accident, 1974, with residual left hemiparesis

(what would the primary dx be? What would the secondary dx be? How did you choose what would be the primary and secondary dx?)
cross posted to ICD-9 coding