He underwent a major heart surgery several years ago.

几年前他心脏动了一次大手术。

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Only 12 weeks ago he underwent major heart transplant surgery.

仅仅12周之前，他接受了一次心脏移植的大手术。

《柯林斯英汉双解大词典》

Even with more major dental surgery, the risk to your heart is likely to be small, especially if you're young and in good health.

即使是更主要的牙科手术，对你的心脏风险可能是小的，尤其如果你是年青人和身体健康的。

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It turned out I had a rare virus that had attacked the muscles in my heart and as a result, I ended up having major heart surgery -- bypasses of five arteries.

CNN: 'I'd be an invalid without this device'

This was his first scheduled trip abroad since one to Central Asia in October was cut short by illness Mr Yeltsin has a history of poor health, undergoing major heart surgery just over two years ago.

BBC: News | Europe | Yeltsin rushed to hospital

Major open-heart surgery, which involves cracking the ribs, is necessary to install the CorCap.

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