Когда приступ закончился, пациенту стало лучше.

Because Когда приступ закончился is a subordinate clause introduced by когда (when). In Russian, subordinate clauses are separated from the main clause with a comma.

So the sentence is structured like this:

• Когда приступ закончился, — subordinate time clause
• пациенту стало лучше — main clause

You could also reverse the order:

• Пациенту стало лучше, когда приступ закончился.

The comma is still required.

Here когда means when and introduces a time clause.

So:

• Когда приступ закончился = When the attack ended

It is not asking a question here. It is functioning as a conjunction, not as an interrogative word.

Because приступ is the subject of закончился.

In this clause:

• приступ = the attack / episode
• закончился = ended

So literally: the attack ended.

Since it is the subject, it stays in the nominative.

Закончился is the perfective past tense, which presents the event as completed: the attack ended.

• закончился = ended, came to an end
• заканчивался = was ending, used to end, was in the process of ending

In this sentence, the ending of the attack is a completed event that happened before the patient felt better, so perfective is the natural choice.

In this verb, -ся is part of the verb itself: закончиться = to end / to come to an end.

Compare:

• закончить что-то = to finish something
• закончиться = to end

So:

• Врач закончил процедуру. = The doctor finished the procedure.
• Процедура закончилась. = The procedure ended.

Here приступ закончился means the attack ended.

Because Russian often uses the dative case with expressions about someone’s physical or emotional state, especially in impersonal constructions.

So:

• пациенту = to the patient
• literally: it became better to the patient
• naturally: the patient felt better or the patient got better

This pattern is very common:

• мне плохо = I feel bad
• ему лучше = he feels better
• пациенту стало хуже = the patient became worse

Because this is an impersonal construction.

Russian often says things like:

• мне стало лучше
• ему стало плохо
• ребёнку стало холодно

There is no normal grammatical subject here, so the verb in the past tense appears in the neuter singular form:

• стало

It does not agree with пациенту, because пациенту is dative, not the subject.

So although English says the patient felt better, Russian structures it more like it became better for the patient.

Because лучше is the comparative form meaning better.

Here it is used as a predicative state word after стало:

• стало лучше = became better

This лучше does not change for gender, number, or case in this construction.

Compare:

• Ему лучше. = He feels better.
• Пациенту стало лучше. = The patient felt better / got better.

By contrast, лучший means best or better as an adjective modifying a noun, for example:

• лучший врач = the best doctor

So in this sentence, лучше is the correct form.

Yes, very common.

Russian often expresses improving or worsening health with:

• стало лучше = became better / felt better
• стало хуже = became worse
• ему лучше = he feels better
• ей уже лучше = she already feels better

This is one of the most natural ways to talk about health or condition.

Usually not in this meaning.

Пациент стал лучше sounds odd, because it suggests the patient became better in a more abstract or personal sense, not specifically that his condition improved.

For health, Russian normally says:

• пациенту стало лучше
• состояние пациента улучшилось
• пациент стал чувствовать себя лучше

So пациенту стало лучше is the most natural short version here.

Приступ can mean an attack, fit, seizure, or episode, depending on the medical context.

For example, it can refer to:

• an asthma attack
• a seizure
• a coughing fit
• a pain episode

So the best English translation depends on the situation. The Russian sentence itself does not specify what kind of attack it was.

No, Russian word order is flexible.

This sentence:

• Когда приступ закончился, пациенту стало лучше.

could also be:

• Пациенту стало лучше, когда приступ закончился.

Both mean essentially the same thing. The version with Когда... first puts the time frame first: When the attack ended...

Russian word order often changes for emphasis, information flow, or style rather than basic grammar alone.

A very literal breakdown is:

• Когда = when
• приступ = attack / episode
• закончился = ended
• пациенту = to the patient
• стало = it became
• лучше = better

So literally:

• When the attack ended, it became better to the patient.

That is not natural English, but it helps explain the Russian grammar.

With stress marks:

Когда́ при́ступ зако́нчился, пацие́нту ста́ло лу́чше.

Approximate pronunciation:

• когда́ = kag-DA
• при́ступ = PREE-stoop
• зако́нчился = za-KON-chil-sya
• пацие́нту = pa-tsi-YEN-too
• ста́ло = STA-la
• лу́чше = LOO-chshe

For learners, the most useful stresses to remember are:

• когда́
• при́ступ
• зако́нчился
• пацие́нту
• ста́ло
• лу́чше