Пацієнт зателефонував до реєстратури.

Зателефонував is the past tense of зателефонувати, which is a perfective verb.

That tells you two things:

• it means to make a call / to call once
• the action is seen as completed

So Пацієнт зателефонував до реєстратури means the patient did call the reception/registration desk.

A useful contrast:

• телефонував = was calling / called / used to call, with more focus on the process or repeated action
• зателефонував = called once, successfully initiated the call

That ending shows past tense masculine singular.

In Ukrainian past tense, the verb agrees with the subject in gender and number:

• зателефонував = masculine singular
• зателефонувала = feminine singular
• зателефонувало = neuter singular
• зателефонували = plural

Since пацієнт is a masculine singular noun, the verb is зателефонував.

Here до means to in the sense of to a place/department/institution.

So:

• до реєстратури = to the reception / to the registration desk

This is a very common pattern with places or offices. After до, the noun goes into the genitive case, which is why реєстратура changes to реєстратури.

A useful comparison:

• зателефонувати лікарю = call the doctor
  
  • here the person is in the dative
• зателефонувати до реєстратури = call the reception/registration desk
  
  • here the place/institution is introduced with до + genitive

Реєстратури is the genitive singular form of реєстратура.

Base form:

• реєстратура = registration desk, reception, admissions office

After the preposition до, Ukrainian requires the genitive:

• до реєстратури

For many feminine nouns ending in -а, the genitive singular ends in -и or -і, so:

• реєстратура → реєстратури

In a medical context, реєстратура usually means the reception, front desk, or registration desk/office in a clinic or hospital.

It does not usually mean a general abstract idea like English registration.

So in this sentence, a natural English meaning would be something like:

• the reception
• the front desk
• the registration desk at the clinic

Пацієнт is in the nominative singular, because it is the subject of the sentence — the one doing the action.

Dictionary form:

• пацієнт = patient

Since the patient is the one who called, nominative is used:

• Пацієнт зателефонував...

If the noun had another role in the sentence, its form might change.

Ukrainian does not use articles like English a or the.

So пацієнт can mean:

• a patient
• the patient

and реєстратури can mean:

• of a registration desk
• of the registration desk

The exact meaning depends on context.

That is completely normal in Ukrainian.

Yes. Ukrainian word order is fairly flexible because case endings show grammatical roles.

The neutral order here is:

• Пацієнт зателефонував до реєстратури.

But other orders are possible, for example:

• До реєстратури зателефонував пацієнт.
• Зателефонував пацієнт до реєстратури.

These can shift the emphasis:

• starting with пацієнт emphasizes who
• starting with до реєстратури emphasizes where he called
• starting with the verb can sound more narrative or stylistic

The original sentence is a normal, neutral way to say it.

A rough pronunciation guide is:

• Пацієнт → pa-tsi-YENT
• зателефонував → za-te-le-fo-nu-VAV
• до → do
• реєстратури → re-ye-stra-TU-ry

The main stresses are:

• паціє́нт
• зателефонува́в
• реєстрату́ри

A few helpful notes:

• є in пацієнт and реєстратури has a ye sound
• Ukrainian г is not a hard English g
• Ukrainian и is not exactly English ee or ih; it is its own vowel sound

Yes, those are possible, but they are not exactly the same.

• зателефонував = called by phone; fairly neutral and standard
• подзвонив = called/rang; common in everyday speech
• дзвонив = was calling / called, often imperfective or process-focused

So this sentence with зателефонував sounds natural and standard, especially in neutral or slightly formal Ukrainian.

It is neutral to slightly formal, mostly because of the words used:

• пацієнт is a standard, medical-context word
• реєстратура is also a standard institutional word
• зателефонував is a normal standard verb

This sounds exactly like something you might read or hear in a clinic, medical note, or ordinary formal conversation.