This is the dramatic moment Coast Guard crews rescued a cruise ship passenger suffering from a cardiac emergency during a tsunami alert.

Watchstanders at the Coast Guard Northwest District Command Centre received a medevac request from the cruise ship Carnival Legend for a woman, 71, on Tuesday, July 29, around 6 pm.

The ship was reportedly sailing from Prince Rupert, British Columbia, to San Francisco, California.

Rescue crews reached the vessel located nearly 120 miles west of Grays Harbor, Washington, at 8:49 pm.

Footage shows a helicopter crew being lowered onto the deck to assist the patient.

The elderly person was airlifted to Coast Guard Air Station Astoria and was then transferred to emergency medical services for further care.

Commander Neal Corbin, commanding officer of Air Station Astoria, said: 'While carrying out a critical long-range medical evacuation from a cruise ship, Coast Guard Northwest District units also stood ready to respond to the threat of a distant tsunami.

'Their ability to answer both calls at once is a powerful testament to the Service's unwavering dedication to saving lives and protecting the maritime community.'

Tsunami alerts had been issued for the Washington coast following a powerful 8.8-magnitude earthquake off Russia's eastern shore.