When did the NFL Cardinals gain the name Cardiac Cardinals and after what particular game?

They gained the nickname Cardiac cardinal towards the end of the 1998 season, butthere's not much around specifying after which game.

By reaching the playoffs for the first time since 1982, and then winning a playoff game for the first time since 1947, the Cardinals exceeded most expectations. While this team showed it should be considered a franchise on the rise, it wasn’t always easy. They earned the nickname "Cardiac Cardinals" because eight of their 16 regular-season games were decided by three points or less, with seven of those ending in favor of Arizona. However, until the playoffs, when they beat archrival Dallas, the Cardinals had not defeated a team with a winning record. ... Said QB Jake Plummer after the season-ending loss in Minnesota: "We can look back in a few weeks, and then we’ll reflect on how we put together a pretty good season against some pretty high odds. We finished it out, made the playoffs and did some good stuff."

[ archive.profootballweekly.com/content/archives/features_1998/seasonreview_cardinals_020399.asp ]
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http://www.arizonasportsfans.com/forum/threads/jake-plummer-was-one-win-from-the-super-bowl.67208/page-8

One of the keys for Plummer is to get Arizona off to a quicker start. The Cardinals have been outscored 104-19 in the first quarter this year. Plummer, who helped Arizona achieve the nickname ``Cardiac Cardinals' a year ago with his flare for late-game and late-season dramatics, has helped Arizona outscore its opponents 80-65 in the fourth quarter this year, but it's not nearly enough to erase most of the deficits.

[ augustasports.com/stories/122599/pro_falcons.shtml link no longer exists ]

Actually the term was first applied in the mid 1970s when the team was doing quite well under coach Don Coryell (cf. https://en.wikipedia.org/wiki/Don_Coryell ;later led the Chargers to several division titles -- remember Air Coryell). Many of their games were quite close (both wins and losses). Because of these "nailbiters," they began to be called the Cardiac Cardinals -- about 25 years before the 1998 season. https://en.wikipedia.org/wiki/Arizona_Cardinals

Matt602Kent is correct. I remember as a kid watching those close games, and my heart would be pounding out of my chest out of anxiousness and anticipation of a possible win (I was thinking, "are they going to be able to pull this one off?!").

The sportscasters throughout the late '70s and '80s here in St. Louis would always refer to them as the "Cardiac Cards" or the "Big Red" (the later to differentiate themselves from the baseball Cardinals).

But to go to the original trivia question...I have no idea...was there a specific game? I figured it was a nickname that was applied to them over a long period of time.