Jon Niese leaves with rapid heartbeat

NEW YORK -- New York Mets left-hander Jon Niese was pulled from Sunday's game against the St. Louis Cardinals after tossing six scoreless innings as a precaution because he experienced a rapid heartbeat during the game. It was the same issue that forced Niese from a game last season at Texas as well.

Niese said the issue arose during the fourth inning, which coincided with him running the bases. His heartbeat had normalized by the completion of the Mets' 6-1 win, he added.

Manager Terry Collins said Niese will undergo medical testing Monday.

"It's just one of those things where the heart starts racing and things get excited -- and exciting -- and it just won't slow down," Niese said. "I feel good now. I'm sure with a good night's rest I'll be ready."

Niese also was pulled from a June 25, 2011 game in Arlington, Texas, with the same symptoms, which he described as comparable to feeling an adrenaline rush.

He wore a Holter monitor for 24 hours after that episode and an echocardiogram and an EKG were performed at Henry Ford Hospital in Detroit -- the Mets' next stop on that road trip. Doctors did not detect anything alarming at the time, Niese said, and the issue largely was dropped.

"I did tests last time and everything came up normal," Niese said. "I'm sure that's how this is going to end up. ... I never had an issue with it afterwards, and I'm sure I won't this time."

Niese said last June that he had experienced similar rapid heartbeats on the mound "on occasion" in the past. There was curiosity in Arlington about whether the extreme heat contributed, but on this occasion the temperature was a comfortable 69 degrees at first pitch at Citi Field.

Niese said he has not undergone any special heart testing between the Texas episode and Sunday's recurrence -- except for the EKG that is generally performed on all players during spring training. Niese said there was no further testing required when he signed a five-year, $25.5 million extension on the eve of Opening Day.

He added that the issue is not scary for him.

"Not really, just because I've felt it before, and I know it's not an issue," Niese said. "It's not something that hinders my performance. I don't feel any pain. It's just one of those things, it's kind of like a huge adrenaline rush. It's one of things where your heart just races."

Although Niese's pitch count was at 96 after six scoreless innings, Collins acknowledged he specifically removed the southpaw from Sunday's game as a precaution because of the heart issue. Collins had visited Niese at the mound with two outs and none on in the fifth inning before Matt Holliday batted, which raised suspicions something might be amiss.

"Just as a precaution we're going to have him checked," Collins said. "He's had it before, so he knows what it feels like. When he sat down on the bench, he said he felt better. He went back out on the mound, started the inning, and we were watching him real close. I'm sure you guys saw he started walking around the mound a couple of times, and I said, 'Uhh, I don't like the looks of that,' so I went out to just see if he was OK. And he was."