How Damaging is Low CTR On Entire Adwords Account?

[louis]

How Damaging is Low CTR On Entire Adwords Account?
Hey guys, I am just wondering how harmful a low CTR for a handful of keywords (with high impressions) is on an entire campaign with thousands of keywords (in separate Ad Groups) and the entire acount (other campaigns)? The low CTR keyword has the majority of the searches for the campaign.
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SEO
SEO UK