Is this a precondition? Will it be covered by insurance?

[insubuy]

This will definitely be considered as pre-existing conditions and NOT covered by visitor medical insurance plans for visitors to USA.

[submittedviaemail]

My mother had high blood pressure. She visited US 3 years ago. During that visit, she had a stroke and was sent to the emergency room. She recovered very well. Now she's planning to come here for a short visit. If anything happens, e.g. another stroke caused by high blood pressure, will that be considered precondition? Will that be covered?