Miss Holloway had a weak heart. She must have had a heart attack.

霍洛韦小姐心脏衰弱。她一定得过心脏病。

《柯林斯英汉双解大词典》

My colleagues and I have sent a number of orphans to the US and Canada for free operations. One is a little girl named Xiao Chu who was born with a weak heart.

我和我的同事把很多孤儿送到了美国和加拿大免费做手术，其中有一个女孩叫肖楚(音译)，有先天性心脏病，婴儿时就被遗弃了，两岁时就呼吸困难，没有了食欲，她的前景看来很危险。

youdao

He had a weak heart, and not enough care was taken - that is, they probably should not have operated on him.

他有一颗虚弱的心脏，没能够得到精心保护——也就是说，他们或许不应该对他施行手术。

youdao

They may have a weak or damaged heart, high blood pressure or other problems of the blood system.

VOA: special.2010.07.27

In healthy women the drugs don't appear to save lives at all, and the evidence they prevent heart disease is weak: Statin takers have only a slightly better chance of avoiding heart disease than women on a placebo, according to a recent analysis.

FORBES: On The Cover/Top Stories

Moreover, weak drugs targeting a PPAR receptor associated with heart disease have been around for decades.

FORBES: Cancer Worries Dog New Anti-Fat Drugs