Pusoko

~Ang Puso Ko [Puso and Ko or My Heart are two different Word, you don't write it as one]

*Titles like this usually have the Definite Article "Ang"

tatlong linggo ang nakalipas, pumunta ako sa aspital. 

~Tatlong linggo na ang nakalilipas (nang) pumunta ako sa ospital.

*Nakalilipas here is in present perfect progressive, meaning the action is between 'before now' and 'now', ex. It has been 3 weeks since I went to the doctor.

*you can also use the word 'nakararaan':

~Tatlong linggo na ang nakararaan nang pumunta ako sa ospital.

*If you want it to sound quite poetic, "nang" can be omitted that's why it's enclosed to (). However, the preceding sentences show that it is an essay. So using "nang" is advisable.

Nagkaroon ako ang pumunta sa cardiologist.

*If you mean to say you were sick or you fill some kind of pain (chest pain, or other cardio illness) and visit a cardiologist, then your sentence should be:

~Nagkaroon ako ng karamdaman / Nakaramdam ako ng pananakit ng dibdib, kaya pumunta ako sa cardiologist.

*Nagkaroon ako ng karamdaman=I've had an illness

  Nakaramdam ako ng pananakit ng dibdib=I've had chest pain

  kaya=so

  pumunta ako sa cardiologist=I visit/came to visit/had an appointment to the cardiologist

Nakinig manggamot sa akin puso at gumawa ng echo.

*if you mean the doctor examine/listen to your heartbeat and done the 2d echo, you can say it like this:

~Sinuri ako ng doktor or manggagamot, pinakinggan ang tibok ng puso ko at sumailalim ako sa 2d echo test.

*doktor can also be used instead of manggagamot, especially in coloquial situation.  

*sumailalim=undergone

ngayon pumunta mauli sa ospital.

~Ngayon, pumunta akong muli sa ospital=Now, i went to the hospital again

~Kaya ngayon, narito akong muli sa hospital=And now, I am here again at the hospital

Sinabihan ako manggamot ang pusoko ay malusog.

~Sinabi sa akin ng manggagamot na ang puso ko ay malusog=The doctor said to me or told me that my heart is healthy.

*"Sinabihan" is used for third person degree

* sa akin=to me, na=that 

Sinabi ko sa mangamot "salamat, nagkaroon ako ang uuwi sa ospital sa tatlo taon?"

~Sinabi ko sa manggagamot, "Salamat, kailangan ko bang bumalik pagkatapos ng tatlong taon?" = Thank you, do I have to came back after three years?. have to=kailangan

"Oo" sinabi (sabi) mangamot (sa) ako.

 ~"Oo" ang sabi ng manggagamot sa akin.

*you can use "sagot"[answer] instead of "sabi", because the doctor answered your question, so:

~"Oo," ang sagot ng manggagamot sa akin.

"Hangang sa muli sa tatlo taon!"

*if you mean "Till we meet again after three years then!".. you can say it like this:

~Hanggang sa muli nating pagkikita, pagkatapos ng 3 taon!

~Magkita na lang uli tayo pagkatapos ng 3 taon! 

You seem to have a difficulty in possessive nouns and pronouns. Hope the ff. may help you:

Meron akong bagong kotse=I have a new car 

*ako[I]pronoun, 1st person

It was given to me by my grandfather=Ibinigay sa akin ang kotseng ito ng lolo ko or aking lolo

*sa akin, or sa'kin if abbreviated[to me] possessive noun, 1st person

*ko[my] possessive noun, 1st person

Ako ang paboritong apo ng aking lolo.=I am my grandfather's favorite grandson.

*ako[I]pronoun, 1st person

*akin[my] possessive, 1st person

**As you can see, 1st person possesive "akin, ko" is in english [my,mine]

examples: laruan ko / aking laruan = my toys/the toys are mine ; bahay ko / aking bahay = my house/the house is mine

*"ko" is used after the subject, while "akin" is used before the subject

*"aking~" is usually use for poetic sentences, because it is in a deeper level of tagalog

*as for 2nd person possessive noun [mo, iyo = your, yours] here are the examples: pagibig mo or iyong pagibig = your love ; iyon iyan or iyan ay iyo = that's yours

*"mo" is used after the subject, while "iyo" is used before the subject

*like "aking~", "iyong~" is use for poetic sentences

Ang puso ko

Tatlong linggo ang nakalilipas, pumunta ako sa Ospital.
Nagkaroon ako ang pumunta sa cardiologist.-anong nais mong sabihin rito?
Nakarinig ang manggamot ng pintig sa aking pusosa akin puso at gumawa ng echo.
ngayon pumunta mauli ako sa ospital.
Sinabihan ako ng manggamot na ang puso_ko ay malusog.
Ang sinabi ko sa mangamot ay "salamat, nagkaroon ako ang uuwi sa
ospital sa tatlo taon?" -> anong nais mong sabihin sa ingles dito? "Oo" sinabi (sabi) ng mangamot sa akin. (sa) ako.
"Hangang sa muli sa tatlo taon!"

Ang Puso Ko = My Heart

Tatlong linggo na ang nakalipas mula nang pumunta ako sa ospital. = Three weeks have passed since I went to the hospital.

Nagkaroon ako (ng kakaibang pakiramdam kaya ako) pumunta sa cardiologist. = I had (an abnormal/unusual feeling that is why I) went to a cardiologist.

Pinakinggan ng manggagamot/doktor and aking puso at pinagawan ng “2D echo test” (maybe that’s what you meant?) = The doctor listened to my heart and had a 2D Echo test made.

Ngayon, pumunta uli ako sa ospital. = Now, I again went to the hospital

Sinabihan ako ng manggagamot/doktor na ang puso ko ay malusog. = The doctor told me that my heart is healthy.

Sinabi/Sabi ko sa manggagamot/doktor, “Salamat. Kailangan ko bang bumalik sa ospital pagkalipas ng tatlong taon?” = I told the doctor, “Thank you. Do I need to go back to the hospital after 3 years?”

“Oo”, ang sinabi/sabi ng manggagamot sa akin. = “Yes,” was what the doctor told me. (or “Oo,” ang sinabi/sabi ng manggagamot ko. = “Yes,” was what my doctor said).

Hanggang sa muli, sa tatlong taon! = Until then, in 3 years’ time! (or “Hanggang sa tatlong taon uli!”. = Until/After 3 years again!

“Nakinig” and “pinakinggan” both mean “listened”. The distinction between them is that “nakinig” usually refers to listening in a natural way, like without having to make an effort to hear or listen. It’s what we use to refer to listening to the radio or music, for example. “Pinakinggan” usually means listening attentively or making an effort to hear or listen to a sound. Since a doctor has to use a stethoscope to listen to the sound of the heart and also listens closely for any sign of irregularity in the sound, we use “pinakinggan”.