a cat coming

[yakor]

Hi!
Which part of the sentense is "coming" in
-I saw a cat coming.
Is "coming" a noun and "a cat" the determiner of "coming" Or "a cat" is a noun and "coming" is determiner? Also, the same not understanding about
-I heard his heart beating.
"his heart"- the noun + the determiner "beating" OR
"his heart"-determiner+ the noun "beating".

 

[se16teddy]

Some people call coming a present participle agreeing with cat.

I say that verbs of perception can be followed by an object and then either an -ing form or an infinitive.
I heard his heart beating
I heard his heart beat.