병원이라는 말에 가슴이 철렁했어

The line, explained

It is late, the phone buzzes, and a voice says one word you never want to hear: hospital. You have not heard the rest yet. You don't know if it is serious. But your body has already reacted, a cold lurch from chest to stomach. Korean has a perfect idiom for that half-second, built on a sound word, and dramas use it whenever a character takes a terrifying call. Today's line is the heroine telling a friend afterwards, still shaky, what that moment felt like.

병원이라는 is 병원, "hospital", with -이라는, a shortened quoting form of -이라고 하는, "that is called". So 병원이라는 말 is "the word hospital", literally "the word that goes hospital". 말에 is 말, "word, speech", with 에, which here marks the cause: "at, upon hearing". Korean often attaches the trigger of an emotion with 에: 그 소리에 놀랐어, "I was startled by that sound". The ㄴ of 병원 links forward, so it sounds like byeong-wo-ni-ra-neun.

가슴이 is 가슴, "chest", with the subject marker 이. Korean puts many strong feelings in the 가슴 rather than the 마음: 가슴이 아프다, "heartache", 가슴이 뛰다, "heart racing". 철렁했어 is 철렁하다 in the past. 철렁 is a mimetic word, originally the sound and feel of a big body of water suddenly sloshing and dropping. Attached to 가슴, it pictures your heart plunging like a bucket into a well. The two ㄹ sounds merge, so you hear cheol-leong.

The idiom almost always appears in the past, because by the time you can talk, the drop has already happened. You will often hear the longer 가슴이 철렁 내려앉았어, "my heart sank right down", with 내려앉다, "to settle, to cave in". 심장이 철렁했어 uses 심장, the heart as an organ, for a more physical feel. The cause comes first, with 에 or a clause: 문자 보고 가슴이 철렁했어. For a smaller scare, Koreans simply say 깜짝 놀랐어, "I was startled".

Swap the frightening word: 사고라는 말에 (at the word "accident"), 이별이라는 말에 ("breakup"), 수술이라는 말에 ("surgery"), 경찰이라는 말에 ("police"). Notice that 사고 ends in a vowel, so it takes -라는, while the others end in a consonant and take -이라는. In real life you will hear the idiom most from parents: after a child wanders off in a supermarket for twenty seconds, 가슴이 철렁했잖아 is how the scolding begins.