I can't really imagine an implanted heart pump that couldn't be dangerous.
“Defective” could have been more precise, and would match the reporting (though I kept the title close to the source material’s to meet HN guidelines, truncating the start to meet the character limit).
You'd be surprised. FDA rules require medical products to be safe, among other things. An implanted pump that's dangerous is the exception, not the rule (as it should be).