Kenley Jansen knew immediately what was happening. His heart was racing. His chest was tight. Each breath was a gasp.
The same thing had happened in 2011 and 2012, each time when he was in the high altitude of Colorado. His heart was in atrial fibrillation.
Most people would be terrified. Jansen was mad.
"I wasn't scared. I knew exactly what it was," he says now. "I was pissed.
"I thought my season was over. I'm like, man, f--- this. Not again. We're trying to go back to the World Series. I have a chance to win another Trevor Hoffman award.